All LED Lights on Trailer Work Except Running Lights When Hooked To 2008 Chevrolet Silverado

Updated 06/25/2020 | Published 01/06/2011

Products Featured in This Question

LED Combination Tail Light Kit for Trailers under 80" Wide - Submersible - Driver and Passenger

(3281)

$65.99

7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End

(2638)

$43.50

Hook Probe Circuit Tester

(60)

$12.41

Question:

I installed the LED kit per instructions, all signals work, break lights, etc... however, the running lights are not working when the vehicle lights are on. this includes the additional two orange leds i installed on the side of the trailer...any suggestions? the trailer is wired into a 4 flat and my vehicle has a 7 round/pin and i bought a new adapter...just cant understand why the running lights wont work..they are wired into the brown wires on each side. 2008 Chevy silverado.

asked by: Brad

Expert Reply:

There are a few possibilities and things you will need to check on your trailer and your vehicle.

You will want to start by checking the ground wires on the lights, make sure each light has a good ground connection to clean metal surface.

Then, you will want to check the wiring on the trailer, start at the 4-way connector and visually inspect the wires for any cut or exposed wiring. If you find cut or exposed wiring where the protective coating on the wiring is missing, you will want to replace the wiring.

After that, you will want to test the 7-way connector at the 11 o'clock position using a circuit tester like part # PTW2993, to see if you are getting power. If there is no power going to the 11 o'clock pin on the 7-way, there is a possibility that the towing package fuse is blown on your vehicle. You will want to check the Accessory Fuse in the Fuse Box under the hood of your vehicle. Underneath the cover of the fuse box or on the outside of the fuse box the function of each fuse should be labeled. The blown fuse could have been caused by any exposed or cut wiring on the trailer creating a short circuit.

If you find that the accessory fuse is blown, before replacing it you will want to inspect the wiring on your trailing for any exposed, cut, or frayed wires. You will want to repair or replace any wiring that is exposed as it may have caused your fuse to blow.

If you find that the fuse is not blown, there may be some corrosion in the 7-way connector of your vehicle. If you find that the there is corrosion, you will need to replace the 7-way on your vehicle, for this I would recommend Hopkins 7 and 4 Way Trailer Connector, part # HM40975. The Hopkins # HM40975, will give you a 4 and 7-way connector at the rear of your 2008 Chevrolet Silverado and you eliminate the need for an adapter.

I have linked an FAQ on wiring that you may find as a good reference and a video installation of the Hopkins 7 and 4 Way Trailer Connector, part # HM40975 on a Chevrolet Tahoe that should be similar to installation on your 2008 Silverado.

expert reply by: Reno H

Steve

5/19/2020

I have a similar question. I have completed many LED conversions and trailer rewiring projects. I installed your LED rear tail lights left and right and added two small, amber clearance lights. All lights wiring have been run to a central junction box on the tongue. All wires are terminated using heat shrink eyes and connectors. Connections at the rear lights are completed using heat shrink connectors, then are covered with heat shrink tubing on top of that. I know a little overboard but doing it this way assures a long lasting connection. All dedicated wiring, each light has its own wire to the junction. I ran a ground wire for each and wired the grounds to the trailer plug. Chasing the problem I installed a brand new, molding trailer plug & wire to the junction box and even replaced the truck side plugin. 2015 Silverado. Here is the problem: the running/parking/clearance lights don't operate properly. Only the amber light and side portion of the rear lights work and even then, are no bright. No running lights in the large rear light fixtures. I disconnected all the running lights at the junction and tested the voltage. I have 11 volts coming from the trailer plug lead when the leads are not connected to anything. The voltage drops to 3 volts when all the running lights are connected. In an effort to diagnose the problem, I only connected one to the small LED amber clearance light and the voltage drops to 6 volts. Both blinkers and brake light work perfectly, very bright and as I expected. I have run continuity tests on the wiring using a Fluke meter and all are fine. I've never had any problem like this. Do I need resistors?

Chris R.

5/22/2020

You have ruled just about everything out....I do think adding resistors # P230004A-2 in-line with the running lights circuit is the next step. Since those LEDs require so little power, the running lights circuit on the tow vehicle might just need a little extra "umph" for it to continue to send back full power when activated. I would definitely try this - if it doesn't work for some reason let me know.

Steve S.

5/22/2020

@ChrisR Yes, I'll give that a try. I believe it will work. Thanks, love eTrailer.