Troubleshooting Hopkins 7-way Connector # HM48503 Having All Test Lights On But No Trailer Lights

Updated 05/26/2021 | Published 05/23/2021

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Question:

we have wired the hm48503 Aux/power light is lit. Once we have connected it to the vehicle and the vehicle is started, All lights on the tester function come on, except the brake light, no flashing lights, just solid. None of the lights work on the camper/trailer. no running lights, left turn or right turn signal, or brake light.

asked by: Debra H

Expert Reply:

That is definetly unusual for all of the lights on the Hopkins 7-Way # HM48503 to be on at the same time, as that would mean that power is getting sent to all of the pins on your vehicles 7-way connector at the same time.

Since there are no lights working on the trailer, I recommend checking the vehicle side 7-way connector with a circuit tester like # PTW2993 while a friend goes turns on the turn signals and applies the brakes and running lights one at a time.

If you find that all of the functions are indeed coming on at the same time you will need to check the vehicle connector for any debris or corrosion.

Next check that no debris go into the new # HM48503 you installed on the trailer, and verify that the main ground on the tongue of the trailer is connected to clean corrosion free metal.

If this does not fix the issue let me know and we will go into more in-depth troubleshooting steps.

I included a link to a helpful article on wiring for you to take a look at.

expert reply by: Samuel C