Troubleshooting Trailer Left Blinker Not Functioning on a 2004 Ford F-150

Question:

Yes I have a 2004 ford f 150. When I hook it up to my trailer the right side trailer lights work but the left side do not. I have check the grounds and the fuses. Ive also put used a 3808 checker to check the both sides of the plug on my truck . At the plug the right side will blink and work properly like its supposed to . But the left side does not. I can only get a solid light to come on when I check it. It wont blink with the blinker on. Im not sure what to do . Thank u and God bless.

asked by: Matthew S

Helpful Expert Reply:

Does the left blinker work on the truck? If it isn't working properly it can also prevent the trailer wiring from working depending on what type of trailer wiring setup you have.

Try testing again with the circuit tester with the hazard lights on to see if the circuit starts to blink. That would indicate that the problem is a relay or fuse. But since you said you checked the fuses it's most likely a relay.

Check the owners manual/fuse legend on the truck to see where the relays would be located.

expert reply by: Jameson C