Suddenly I'm having problems with the right indicator on my trailer. When I test the trailer plug on the truck I only get 0.3 volts pulsing. I checked fuses under hood and they are good. What would cause less than 12 volts to be making it o the rear junction block (that thing under the bed by the bumper that has 4 wiring harnesses--one for the trailer lights)? All the lights on the truck work fine. Thanks!
Check the splice where the trailer connector and the truck light wires meet.
Check for any corrosion or broken wires; also check the ground wire (s) for the trailer light itself for the same conditions. Make sure the connector is clean and the wires fit tight in the connector when pushed together.
If the right directions lights work normally on the truck, then it has to be a bad connection at the splices, or the connections at the trailer light or a bad wire itself.
Check the continuity of the wire with an OHM meter. If you have excessive resistance; than replace the entire length of the wire.
Supplying the proper year of the truck will help us help you better.
Hope this helps. Let us know how you make out.
My truck is a 2000 Silverado 1500. It has an amber indicator and red brake lights. Came without trailer package but the wires were already at the rear of the truck so I hooked them up to a 7 way plug several years ago. Everything worked fine until recently when the right indicator and right brake light on the trailer stopped working. Got the same condition on another trailer. When I test the wire supplying the right indicator for the trailer I only get 0.3volts. I disconnected the wiring harness and got 12 volts on one wire (presumably the one supplying the right indicator). I tested the wire supplying the trailer with the right indicator and get good continuity. I even gambled and bought a new rear junction block but that didn't solve the problem. Could it be a problem with whatever is supposed to convert the amber/red truck lights to the single red trailer light?
I found this description of the rear lights. Check all the fuses and concentrate on the Dark Green wire and the White ground wire.
Locate the Engine wiring harness junction block and check the 10 AMP fuses inside, the fuse for the right trailer light might be blown.
It should be located under the left side of the instrument panel near the left kick panel.
I hope this helps.
TRAILER/BRAKE CONTROLLER WIRING INFORMATION
Important The trailer harness and fuses must be connected to the engine wiring harness junction block. The trailer harness circuits are identified in the following table. Please take note of the maximum current ratings of the circuits.
Stop lamps and turn signal lamps are similar to the description in Exterior Lights Circuit Description, with the exception of the following conditions:
From the stop lamp switch, voltage is supplied to the turn/hazard switch on CKT 17 (WHT).
From the turn/hazard switch, voltage is supplied to the TRL L Turn or the TRL R
Turn fuse on CKT 18 (YEL) or CKT 19 (DK GRN).
From the fuse, voltage is supplied to the trailer connector.