Testing Why Left Turn And Stop Wont Work On Trailer On Vehicle Side

Question:

Left turn and stop wont work on trailer. Everything is clean and in good shape . my friend plugged into my trailer and the trailer lights worked so it must be my vehicle . left turn and stop work on my vehicle but not the trailer . i dont get it ive bought new lights and the wires look untouched. It almost looks light it blinks but its very dim

asked by: Kevin S

Expert Reply:

I would recommend checking all the pins on the vehicle's side 7-way using The Hook Probe Circuit Tester # PTW2993. Using this circuit tester will show you if a signal is coming through on the pin you are currently testing. When facing the 7-way using the circuit tester you will test for the proper signal as follows:

1 oclock position = 12 volt hot lead
3 oclock position = right turn/brake light
5 oclock position = brake controller output
7 oclock position = ground
9 oclock position = left turn/brake light
11 oclock position = tail and running lights
Center = reverse lights

You will need someone to sit in your vehicle to help you run through each function while you test the pins. While checking the connectors if you notice corrosion or dirt clean it out using a wire brush. It sounds like the wire is crimped or has a short.

If you still have any issues reach out to me and I will look deeper into it.

I attached a review video link below.