Troubleshooting Malfunctioning Turn Signals on Utility Trailer Towed by 2006 Chevy Silverado

Question:

Hi , I hooked up my utility trailer today for the first time in a few months. I have running lights but no brake lights or turn signals. I have a 2006 silverado ex cab Z71. 4 way flashers work as well. Every now and then when the 4 ways are on they will go dim and sometimes the drivers side wont flash at all. Any info would be great, thanks

asked by: Jason

Expert Reply:

The first thing you will need to do is to test the 4-pole connector on the truck with a circuit tester like # PTW2993. This will tell you if the wiring problem exists on the truck or on the vehicle itself.

The pins on the connector fed by the yellow and green wires should light up your tester when the right turn, left turn and brake lights are activated.

If you do not get any signal on the right or left turn pins, you most likely have a blown fuse. Check the fuse box under the hood.

If the 4-pole connector tests okay, you have confirmed that the wiring problem is on the trailer itself. Begin at the trailer connector, making sure it is not damaged or corroded. Check the location where the white ground wire attaches to the trailer frame, make sure that this connection is secure and is not corroded. Trace the right and left turn/brake wires back to the lamps, looking for pinched wires or wires with cracked insulation. Make sure each lamp is properly grounded either by its ground wire or by its connection with the trailer frame.

Examining these areas will most likely lead you to the problem, but if it does not, please email me back and we will look into some other possibilities. I have linked you to our wiring troubleshooting FAQ article that you might find helpful.

expert reply by: Mike L

Brian B.

5/8/2020

I have a 2006 Chevy Silverado 1500. The left side trailer turn signal will not flash. The right does. I checked voltages at truck connector and when left turn signal is activated it stays hot and does not flash. The turn signal does work on the truck. Any thoughts.

Chris R.

5/11/2020

You at least know that the issue is somewhere on the truck and not on the trailer side (that's half the battle). Most likely there's a short somewhere on this circuit that's sending constant power back - it could be some exposed wiring that's touching bare metal or a neighboring wire. If this is factory trailer wiring though, this might be difficult to inspect (most of it is likely pretty well hidden). You can also visually inspect the connector itself at the bumper. Look for any built up corrosion or debris that needs to be cleaned out. Corrosion can often bridge a couple circuits together. Let me know what you find and we'll go from there.