Roadmaster Hy-Power Diode - (Qty 1)
(185 reviews)
Price: $17.39
Roadmaster Hy-Power Diode - (Qty 1)
Item # RM-790
Retail:$29.08
Our Price: $17.39
You Save: 40%
Orders above $99 qualify for Free Shipping
Need help with installation?
Locate installers near meIn-stock alternatives that can ship today
- All Info
- Reviews (185)
- Q & A (78)
- Videos (1)
- Photos
- Why etrailer?
Roadmaster Accessories and Parts - RM-790
- Tow Bar Wiring
- Diodes
- Roadmaster
Diodes permit electrical current to flow in only one direction - from the motorhome to the car - prevents electrical feedback and the damage it can cause to the towed car's electrical components.
Features:
- Diodes permit electrical current to flow in only one direction - from the motorhome to the car
- Enables trouble free operation of your towed vehicle lights
- Prevents damage to your towed vehicle's electrical components
- Maximum load per diode: 85 amps at 12 volts
- Includes detailed wiring instructions
- Qty: (1) Diodes
- Made in the USA
Note: 4 Diodes are required for most applications (1 left turn/brake, 1 right turn/brake, 2 for tail lights - each side).
790 Roadmaster Hy-Power Diode
Video of Roadmaster Hy-Power Diode - (Qty 1)
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Video Transcript for Review of Roadmaster Tow Bar Wiring Diode - RM-790
Jeff: Hello everybody. This is Jeff at etrailer.com. Today, we're going to take a look at this Roadmaster Hy-Power Diode for a quantity of one. Now this diode will allow your motor home or your RV to power the lights on your tow vehicle without power feedback. The diode will permit electrical current to flow in one direction from the motor home to the car, preventing any electrical feedback and the damage that it can cause to the towed car's electrical components. It takes two power sources and can combine them into this one wire, prevents back feeding from either circuit.
And this part is for a quantity of one diode. Now it is also available in a variety of quantities. You can get the one pack like this one, a two pack, a three pack, or even a four pack. And all those quantities are available on our website.Now for the one pack like this one, you use part number RM-790. The two pack would be RM-792.
A three pack would be RM-793, and the four pack would be RM-794, and those parts are listed on this product page as a related product. Now this does reduce the wiring hassles. You can see these included spade connectors right here. Just pull one off. Then there's two more over here.
These will allow for a nice trouble-free wiring connections, and then the aluminum heat sink design on this will help prevent overheating.On the very back, you can see, it has this self stick pad that you can peel off that and allows you for a nice, easy, secure mounting of the diode. Now maximum load on this is 85 amps at 12 volts per diode. Now four diodes are normally required for most application, one for the left turning brake, one for the right turning brake, and then two for the tail lights, one on each side. But that should do it for the review on this Roadmaster Hy-Power Diode for a quantity of one.
Customer Reviews
Roadmaster Hy-Power Diode - (Qty 1) - RM-790
Average Customer Rating: 4.9 out of 5 stars (185 Customer Reviews)
Diodes permit electrical current to flow in only one direction - from the motorhome to the car - prevents electrical feedback and the damage it can cause to the towed car's electrical components.
- RM-790
by: Cris06/07/2021
I added accessory back up lights to my truck. I wanted them to work with the truck back up lights and be able to turn them on with a switch in the cab. I did not want to chance backfeed when I used the switch, so I bought this. Only have had it installed for a week and no problems works the way I wanted it to.
- RM-790
by: 07 Revolution06/22/2021
Works fine. Took about 5 minutes to get it installed. Thanks etrailer for having the part in stock, shipping it out quickly for a reasonable price.
- RM-790
Jon l - 06/20/2019
by: Jon l.06/20/2018
I needed to charge my tow vehicle battery by taping in to my tail lights on my motor home. This will prevent The tail lights on the tow vehicle from feeding from its own battery. My break buddy was depleting the tow vehicle battery on long trips. Solved my problem!
Comments
Working great, no problems
Jon l - 06/20/2019
- RM-790
by: Brett01/05/2021
Very robust and has lasted. Work exactly as needed and great customer support and quick shipping from etrailer.com. Highly recommend.
- RM-790
by: Craig06/02/2021
The order arrived quickly and the product was exactly as advertised. Installation was simple and quick. Thanks.
- RM-790
JAMES S - 11/21/2018
by: James11/21/2017
Bought this so I could install backup lights on my trailer and also be able to use them as loading light. This has worked out great. I have also purchased several other items from etrailer and have been happy with all of them.
Comments
After a year this Diode has ben flawless works great for my application.
JAMES S - 11/21/2018
- RM-790
George C - 07/31/2015
George C - 08/04/2015
by: George C.07/31/2014
This diode was easily installed and functions extremely well, as do all of the products we have purchased from etrailer.com. etrailer's extremely competitive prices, their outstanding customer service, and their free, quick delivery make them our go to company for all of our towing needs.
Comments
The products are performing perfectly!
George C - 07/31/2015Comments
We love the equipment that we purchased from you. We have had no issues with towing our Miata.Thank you for your correspondence.
George C - 08/04/2015
- RM-790
by: David02/01/2021
etrailer is the best, I order they send, fast, also have great install videos that without would have taken me twice the time to install.
- RM-790
by: Mike T01/14/2017
Fantastic. The advice received from E-Trailer was perfect. The Diode was exactly what I needed. Small, inexpensive, and very effective. The adhesive back and included connectors couldn't have been a better fit. Needed this to prevent backfeeding of a Motorcycle Lift Battery in my pickup from powering the truck. Truck required a disconnect of the negative battery cable before towing behind a motorhome.
- RM-790
by: Ralph10/26/2020
E trailer is an excellent resource for rv owners that want tech advice and support and a supply system that lets you optimize what You can do as an owner to maintain your rv. Quick shipping and very competitive prices.
- RM-790
by: Paul12/05/2019
I am in awe how quickly this order was processed and delivered. Considering it had to clear Canadian customs and I ordered on a Friday , it was in my hands on Wednesday. Megan was very helpful on the phone in locating the correct parts ,processing the order and following up with tracking info. I had also chat online prior to placing the order with Mackenzie who answered all questions effectively. Combining all this with the fact etrailer has very detailed instructions with drawings on the installation and I am beyond impressed. It isn’t often we see customer service on this caliber today. As a consumer I will definitely be using them again! Oh yeah and the product needed was in stock whereas when I ordered from a well known online site (A...n) in September and told ETA would be Nov/Dec they couldn’t even deliver in that timeline?
- RM-790
by: Jess03/21/2020
This handy item allowed me to wire up my rear bumper flush mount lights to power on with my reverse lights and also power on from a switch. Very handy!
- RM-790
by: Thomas02/04/2018
Nice item, problem solved with my auxiliary lights on the rear of my pickup, lights now work off two switches and no feed back either source. Can put truck in reverse and it doesn't feed power back to switch or i can manually turn them on from the switch and no back feed to my reverse lights. Was nice that it came with butt connectors even tho i have all the electrical connectors, didn't have to search for any. Liked how you can put two power source in and it goes out to one and didn't have to buy two diodes one for each side like traditional diodes. All around nice product and well made. Sorry didn't have a pic to post with it didn't feel like pulling taillight back out.
- RM-790
by: Harold08/18/2021
Fast delivery. Good product
- RM-790
by: Larry02/22/2018
Put it in a snowmobile trailer with a battery and hook the clearance light wire with the one way diode & then to the interior lights so if someone leaves the lights on in the trailer we can still start the pickup when we get back from a 3 day ride
- RM-790
by: Kim04/24/2018
I was amazed to learn that similar to plumbing, you can put a one way valve in a 12 volt wire as well. One of my batteries was not being charged when our RV was plugged in and to make sure I did not run down my engine battery I installed this diode. Simple and came with connections ready to be hooked up. Arrived pretty quickly too. That you Christina J for one on one over the phone help.
- RM-790
by: Jon-Richard04/24/2016
I always have trouble receiving deliveries because I have a postal address that doesn't accept FedEx or UPS and a physical address that doesn't accept USPS. The website doesn't specify the shipping method, so I sent a note to customer service. The rep personally oversaw my shipment so that I got it quickly and at the right destination. It's that kind of service that keeps me coming back to etrailer.com
- RM-790
by: SimiSteve04/11/2019
I bought all Roadmaster parts for my tow car. ALL worked as advertised(GREAT) I thought about a 4 star because slow delivery but you all were helpful.
- RM-790
by: James12/31/2017
This is a little premature to give a product rating. I will say that the diods iordered arrived sooner than expected. After reviewing the options for wiring a vehicle to be towed behind a mtrhome this is the way to process. Thank you, Jim
- RM-790
by: Gene06/21/2017
I used this diode to connect a 12v line from my coach battery to the battery on my CR-V. It helps to keep the CR-V battery from discharging while towing.
- RM-790
Ron - 06/23/2017
by: Ron06/23/2016
I needed these to wire a TOAD (tow vehicle). They have worked as advertised. The plus is that they are quality products. The con is that they are not cheap.
Comments
Over a year and still working well. High quality.
Ron - 06/23/2017
- RM-790
by: Works great08/27/2014
Needed to set up a circuit to activate my reverse lights on the trailer to light up the loading ramp. This worked great to keep the power from backfeeding into the car.
- RM-790
by: Jack10/23/2018
Used on spray equipment wiring to run a foamer with an on/off/on (L-R) switch. Had to eliminate a feedback loop with a high amp diode to run an actuator, this item fit the bill very nicely.
- RM-790
by: Tyson06/11/2021
Easy install
- RM-790
by: Dion10/02/2018
I bought these electrical products for my brother‘s Fiat that he tows behind his moterhome for extra parts haven’t had to use them yet but it’s good to know that etrailer Corp. has the parts thanks George J.
26
190
Show More Reviews
Ask the Experts about this Roadmaster Accessories and Parts
- Can Roadmaster Diode RM-790 be Used for Aftermarket LED Headlight InstallDiodes like the Roadmaster Hy-Power Diode # RM-790 can be used for a wide variety of applications! If your LED headlights are going to be receiving power from 2 sources then use the part # RM-790 that you referenced. If they will only be receiving power from one source you will want to use part # RM-690 instead.
view full answer... - Amperage and Voltage Rating of the Roadmaster Hy-Power Diode # RM-790I spoke with my contact at RoadMaster and the maximum voltage of the Roadmaster Hy-Power Diode, item # RM-790, is 24 volts. The maximum amperage is 85 amps. These are silicon resistors.
view full answer... - Would Roadmaster Diode part # RM-790 Work to Combine Running and Brake Lights on One CircuitIf you were looking for a way to have a single circuit be activated by either your running lights or brake lights the diode part # RM-790 would work for this. The side of the diode with two terminals would take both of the circuits you mentioned and the single side of the diode would go where needed.
view full answer... - How to Fix Brakes Engaging with Right Turn SignalIt sounds like your brake controller is wired to the turn signal wire instead of the brake signal wire. You want the trailer brakes to engage whenever you engage your tow vehicle brakes. Most brake controllers achieve this by sensing both the acceleration in your tow vehicle and that the brake lights have power to them. Wiring the controller to the turn signal would cause your brake controller to send power to the brakes whenever the turn signal flashes. Check the wiring on your vehicle...
view full answer... - Combining Brake and Turn Signals on 2001 Jeep CherokeeFrom what it sounds like you are trying to take your 2001 Jeep Cherokee's separate brake and turn signals and combine them into one. If that's accurate, what will need instead of the diodes is a 3-to-2 converter, the Roadmaster Brite-Lite Wiring Converter # RM-732. I have added a link to a video review and manual for you to check out of this part.
view full answer... - Can a Diode be Used to Power Lights from 2 Different Power SourcesYou hit the nail right square on the head. Using diode # RM-790 as you have described will allow you to power the lights from 2 different sources (one at a time) without back feeding. It would be best to mount the diode where it is protected from the elements. We also have 10 amp on/off toggle switch # PK34513 that you could mount somewhere on the truck. One wire would go to the vehicle battery and the other would go to one of the inputs on the diode.
view full answer... - Diode Recommendation for Taking Two Power Sources from Solar Panels The diode part # RM-790 that you referenced does exactly what you are looking to do. It takes two power sources and can combine them onto one wire and prevents backfeeding from either circuit. So for what you need this would work well.
view full answer... - Are the Roadmaster Hy-Power Diodes Water TightAs long as you are not exceeding the 85 amps at 12 volts per diode max load then you can definitely use the configuration in your diagram. I spoke with my contact at Roadmaster who said that the connections are not watertight but the internal components are. You would either need to find a way to make the connections watertight (as you mentioned in your diagram) or simply wipe the connections off if you were to go off-road with your 2011 Jeep Wrangler and get the diode(s) wet. We...
view full answer...![Image 1 for]()
- Why Do Diodes have Two Input Terminals and Only One OutputDiodes like the part # RM-790 have two wires on the input side so that you can have two different power sources activating a single circuit (the out side) and not have to worry about the power circuits backfeeding on each other.
view full answer... - Electric Brakes are Pulsating When Vehicle Hazards are Activated I have a solutions for your pulsating electric brake issue. Installing the tow Ready Pulse Preventer for Electric Brake Controllers, # 5501, will help eliminate the pulsing in your electric brakes, especially if you have the brake controller set at an aggressive setting. The attached diagram will explain the basic installation of the pulse preventer for you to review.
view full answer...![Image 1 for]()
- Will Diode Prevent Backfeeding of Transfer PumpThe simple answer is yes, the Roadmaster Hy-Power Diode # RM-790 will prevent backfeeding because they allow electrical current to flow in one direction only. There is limitations to the power the diode can safely handle; it has a maximum load of 85 amps at 24 volts per diode so you need to ensure you do not exceed that capacity for it to work.
view full answer... - Explanation of How Diode RM-790 Prevents Circuit BackfeedingDiodes like the part # RM-790 only allow current to flow in one direction. Usually a diode is a small cylindrical shaped component (not in this case) which has two leads on it, the anode and the cathode. When the anode side of the diode is facing towards the positive power source of the voltage it will allow the circuit to be completed and is considered "forward biased." If the cathode side of the diode is facing towards the positive side of the voltage then the diode will not allow...
view full answer... - Is Diode Needed to Prevent Trailer Battery from Backfeeding to Breakaway SystemYes, you will want to use a single function diode, like part # RM-690. You will need to wire it in between the breakaway battery and the trailer battery to stop the backfeeding from the battery to the breakaway system.
view full answer... - Amperage Rating Difference Between Roadmaster RM-790 and RM-690The # RM-690 has a 85 amp capacity and the # RM-790 also has an 85 amp capacity. For preventing backfeed on a circuit either diode will work just fine as long as the amperage of your setup stays under the rating for either diode. The biggest advantage the # RM-790 has other than the higher capacity is that it can be used with two different inputs.
view full answer... - Resistance on the Roadmaster Diode 790I spoke to my contact at Roadmaster and he said that the diode part # RM-790 would have a very minimal amount of resistance. He said that as long as you install the diode properly there would be no way it would generate any trailer light error codes that would pop on your vehicle. I went and grabbed one of these diodes from our warehouse to measure the resistance with an Ohmmeter we have here and found it to show .7 ohms when the Ohmmeter was on the 200 setting.
view full answer... - Maximum Amp Rating of Roadmaster Hy-Power DiodeThe Roadmaster Hy-Power Diode # RM-790 is rated for a maximum of 85 amps. This is for a single diode but is also available in different quantities if you need: - Quantity of 1: Roadmaster Hy-Power Diode # RM-790 - Quantity of 2: Roadmaster Hy-Power Diode # RM-792 - Quantity of 3: Roadmaster Hy-Power Diode # RM-793 - Quantity of 4: Roadmaster Hy-Power Diode # RM-794 I have added links to video reviews for you to check out as well.
view full answer... - Diode Recommendation for Preventing Current Backfeed on 12 Volt Power CircuitFor a single diode to prevent current backfeed the part # RM-790 would be a great option.
view full answer... - Using Roadmaster Hy-Power Diode to Prevent Back-feeding With Trailer LightsThe Roadmaster Hy-Power Diode # RM-790 will work well to prevent back-feeding for your application. You will only need one diode for the system. The wire from the trailer connector will connect at one post on the "in" side, and the wire from the switch will connect at the other post on the "in" side. The wires going to the lights will come from the post on the "out" side.
view full answer... - Can Roadmaster Diode # RM-790 be TestedIf you ran a jumper wire from a 12 volt battery to the input side of the Roadmaster Hy-Power Diode # RM-790 and then used a circuit tester like part # PTW2993 to test the output pin for 12 volts you'd know if the diode was good or not.
view full answer... - What Would Happen if a Diode Received Power on Both Inputs at the Same TimeIf the two power sources are going to be on the same, input side of the diode then the current would flow through it without an issue. If you put power on both sides of the input side of the # RM-790 the current on the output side of the diode would not be affected. Basically the higher current on the two inputs would be the circuit that would make it to the output side. If the current was put on the output side of the diode it would not travel through the diode. Diodes like the part...
view full answer... - Shutting Off Power on 12 Volt Hot Lead so Trailer Does Not Drain Battery on 2012 Chevy SilveradoYou will actually need a battery isolation solenoid, # TR118665. A diode won't be able to do what you want it to do. The solenoid can be installed on the 12 volt power wire going to the trailer connector on your 2012 Chevy Silverado. What happens is when the truck is turned off it will shut off power to that circuit. I have included a picture pointing out what each of the studs is for on the isolator. The 12 volt ignition source is something that only has power when the truck is turned...
view full answer...![Image 1 for]()
- How To Prevent Back Feed From A Deep Cycle Battery On Your TrailerA diode is designed to stop the reverse flow of current in an electrical circuit. Therefore yes, a diode will prevent backfeed to your vehicle from the trailer's battery. The part you referenced part # RM-790 has a dual in, single out function generally used on taillights with multiple power sources. In your case, you will want the Roadmaster Single Park Light Diode part # RM-690 in order to eliminate back feed. To install the diode, you will need to severe the 12 volt hot lead from...
view full answer... - Back Feed Protection from Breakaway Switch to Protect Brake ControllerYou can use a diode # RM-790 to protect your brake controller. Some brake controllers, like the Prodigy P2 # 90885 and P3 # 90195, already have back feed protection built into them.
view full answer... - How to Use Diodes to Have Two Batteries Power a Circuit with No FeedbackYour black drawing would be how wire up the # RM-790 so that both batteries would be on the same circuit but with feedback prevented on the circuits back to the batteries or having them tied together. Basically you would use a diode on each battery line. Using one diode for both batteries would only allow one battery to power the circuit at a time.
view full answer...![Image 1 for]()
- Will Roadmaster Diode # RM-790 Prevent Trailer From BackfeedingYes, the Roadmaster Diode part # RM-790 will prevent the trailer from backfeeding to the battery of your Jeep. You would just need to install it inline with the 12 volt accessory circuit and you would be set.
view full answer... - Diode Recommendation for Preventing Backfeeding with Two Power Sources to One Electric MotorThe Roadmaster Diode part # RM-790 would be exactly what you'd need. It allows two power sources on the input side and only one on the other side which means that one power source couldn't backfeed onto the other. This isn't overkill at all and would be an ideal solution.
view full answer... - Can Roadmaster Hy-Power Diode Work with 37 Amps at 10V InputThe Roadmaster Hy-Power Diode # RM-790 is rated for a max of 85 amps at 12 volts. If you meant to say 37 amps at 10V then this should work out just fine!
view full answer... - Troubleshooting Vehicle with Diode Tow Bar Wiring Kit That Brake Lights Stopped WorkingSounds like maybe the diode of the wiring kit on your vehicle has gone bad. You can bypass the diode to get the brake light to get it to work again, or you can replace the diode with part # RM-790 for if you ever planned to flat tow the vehicle again. If your brake lights are separate from your turn signals you could do what you described and run the brake light wire from one side of the vehicle to the other taillight, but you would also run the risk of overdrawing that circuit since...
view full answer... - Can Roadmaster Diode # RM-790 be Used to Prevent Backfeeding to VehicleThe diode part # RM-790 will prevent the circuit from backfeeding to the tow vehicle. Basically you would pick one of the spades on the IN side of the diode for the side of the wiring from the trailer connector and then the OUT side would go to the battery.
view full answer... - Diode Installation to Allow Both Low Beam and DRL Circuits to Feed Add-On LED Light StripRoadmaster Diode # RM-790 can handle up to 85-amps of current so one should be sufficient to handle both the low beam and daytime running light circuit input signals you want to feed to your LED strip light. It is fine to have two hot leads connected to the one diode so long as the total rating is high enough.
view full answer...
Do you have a question about this Accessories and Part?
Why etrailer.com?
At etrailer.com we guarantee:Highest quality accessories and parts for the best price.
Our Lowest Price Pledge ensures you will never overpay for the parts you need.Real product know-how.
We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.Most detailed, accurate accessories and part information available.
Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.Installations, made easy.
We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.Fast shipping.
Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.Personalized service for life.
We provide one-on-one, personalized service from the ordering process through the life of your product.Trusted since 1946.
We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.Returns Policy
Need to return an item? No problem. Please read our Returns Policy for more information.
Info for this part was:
Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Adam R
Installed by:
Jeff D
Installed by:
Cole B
Updated by:
Hannah L
Updated by:
Mike S
Updated by:
Noah M
At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Product Experts Available Now!
Call 800-298-1624
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.