Troubleshooting Trailer Running Lights Not Working on a 2004 Lincoln Aviator 4-Way

Question:

cant get trailer lights to work on 2004 lincoln aviator.checked fuses and they were good.

asked by: Robert

Expert Reply:

The first thing to do would be to use a circuit tester like our part # 3808 and test the running light function on your vehicle to determine if the problem is on your vehicle or if its on your trailer. Check out the video I attached on how this is done. If voltage is there then you know the problem is on your trailer.

The first place to check there would be the trailer connector. If there is corrosion or cut or exposed wire you will need to fix as necessary. From there trace the running light circuit down the trailer frame fixing any cut or exposed wire. Next check the grounds on the taillight assemblies of your trailer. A weak or insufficient ground is usually the problem for most taillight problems.

If the problem is on your vehicle then I would trace the 4-way back to where it installs into your vehicle wiring and check to make sure the wire you are using for this circuit on your 4-way sees 12 volts only when the running lights of your vehicle are on. You may have found the right circuit but the wire is not making a good connection.

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

expert reply by: Jameson C