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Roadmaster Hy-Power Diode - (Qty 1)

Roadmaster Hy-Power Diode - (Qty 1)

Item # RM-790
Our Price: $16.59
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RM-790 - Diodes Roadmaster Accessories and Parts
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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. 1-833-496-1390 to order Roadmaster accessories and parts part number RM-790 or order online at Free expert support on all Roadmaster products. Guaranteed Lowest Price and Fastest Shipping for Roadmaster Hy-Power Diode - (Qty 1). Accessories and Parts reviews from real customers.
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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.


  • 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 Roadmaster Hy-Power Diode Review

Brad Hello neighbors it's Brad here at etrailer and today we're taking a look at the Roadmaster replacement wiring diode. Now this is available in a quantity of one, two, three or four and this is going to simply just replace an old diode that might have gone bad or if the tab broke. Either way, instead of having to buy a whole new kit, you can simply replace just the diode and that is really nice because the diode is actually user factory wiring that run through them so you still keep your factory lights working properly but if the diode fills, it is very possible that your stop and turn signal as well as your running might not work. So a simple replacement by just taking off the old spade connectors and replacing it can fix that pretty easily. Now only if you do have one that is going bad or you do suspect that, the first thing I would check is definitely the wiring first just to make sure that it is properly connected, but if you deem that this needs to be replaced, no problem. This is going to be a direct replacement.

In fact, if you want, there is actually new spade connectors that are included with the diode so that way you can replace that as well. And if you need to pick up the yellow spade connector here for your cross over wire. You can actually purchase that individually and that way you can really just piece together whatever kit you may need and if you buy multiple quantities, you can actually have an extra set on hands. But having a replacement can get you back on the road and keep you safe and legal. Now these do tend to be extremely reliable.

We don't really have too many people that have issues with them, but it is an electronic component and things can fail especially after a long period of time. So being able to just swap this in and be back on the road flat towing your vehicle safe and legally. It is kind if nice to just be able to replace the diode..

Customer Satisfaction Score:

Customer Reviews

Roadmaster Hy-Power Diode - (Qty 1) - RM-790

Average Customer Rating:  4.9 out of 5 stars   (224 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.


Easy installation instructions. They work great!


Easy to install and solved the lighting problem that I had. I had put a center light in and it became the connection that linked my left and right systems together, causing both blinkers to flash instead of just the one selected. A diode is the answer in this situation. Seemed like a really good quality part too. I’m not sure but might be US made. Etrailer has been a great place to find the things I’ve needed over the years.


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!

Working great, no problems
Jon l - 06/20/2019


Works great


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.


This diode was easily installed and functions extremely well, as do all of the products we have purchased from 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.

The products are performing perfectly!
George C - 07/31/2015
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


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.

After a year this Diode has ben flawless works great for my application.
JAMES S - 11/21/2018


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.


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


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




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.


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.


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?


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.


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.


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.

Over a year and still working well. High quality.
Ron - 06/23/2017


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.


Very robust and has lasted. Work exactly as needed and great customer support and quick shipping from Highly recommend.


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.


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!


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.


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.


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.


The order arrived quickly and the product was exactly as advertised. Installation was simple and quick. Thanks.

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