Troubleshooting Hopkins Active Taillight Converter on 2004 Mercury Grand Marquis No Running Lights

Updated 05/13/2014 | Published 05/12/2014

Question:

So I ordered the hopkins 46255 for my 2004 Merc Grand Marquis. I am very familiar with wiring 12v. Everything is hooked up right, and works fine EXCEPT my tails. They did work one time for like, 10 seconds, and I cant get them to work when my cars tails are powered. Ive changed the ground multiple times and re crimped the brown wires, and still, no tails. I made sure it was the right wire because when I snipped it to re crimp I had no tails on the car. Re crimped, tails on, but still no trailer tails. I get blinkers and brakes no problem. Could this be a faulty controller unit? That is seriously the only thing I can figure by now. Ive tried everything. I bought one of the 4 pin testers, and at the vehicle side, its not lighting up green for the tail I have to move half way across country in a few days and this is driving me nuts

asked by: Sam P

Expert Reply:

To determine if the problem is the converter box of the Hopkins Active Taillight Converter part # 46255 that you referenced you need to test the brown wire on the input side of the box. If you see 12 volts there but then none on the output side of the box then the problem is internal to the box and it will need to be replaced.

If you test the brown wire and there is no voltage then the problem is that the brown wire is not attached to the correct running light circuit.

I also attached an FAQ article on troubleshooting 4-way installs for you to check out.

expert reply by: Jameson C