Troubleshooting Truck Turn Light Function on 2007 Mack Granite When Headlights Are On

Question:

with head lights on right turn wont flash lights up but wont flash left works fine shut headlights off both work ?2007 mack granite

asked by: Rich

Expert Reply:

When you have functions that work correctly when your headlights are off, the wiring has to be connected properly. Since the left works with the lights on, but the right does not, it appears there is not enough power to that right turn signal. This is most likely a ground wire issue. There can be rust or corrosion that will allow connection until power is drawn away. This is not an uncommon issue with vehicles or trailers. I recommend cleaning the ground connection at the light and making sure you have a clean metal on metal connection free of rust, corrosion, or debris. If that doesn't solve your issue, then you will need to use a circuit tester like # PTW2993 to trace your wire so you can find the short and replace the wire as needed.

A little dielectric grease # 11755 will help with wiring connections to keep debris and moisture out to enhance function.

expert reply by: Jason S