Strange electrical issue with trailer. | GTAMotorcycle.com

Strange electrical issue with trailer.

Motorcycle Mike

Motorcycle Mike

Well-known member
Weird... I plug in the trailer, no lights work (left worked briefly the first time, not subsequent trys)

I get out the tester... there is power at the car's plug, there is power at the trailer lights with bulbs removed, bulbs not lighting.

So I test the bulbs... the bulbs turn on if connected straight to a battery, but they don't light up if connected to the wiring plug coming from the car. I test with the voltmeter, and I am getting a consistent 12v both from the battery and from the wiring plug.

Any ideas here? I've never seen that before -- hot wires as tested by a voltmeter, apply them to a bulb and nothing works, but the bulbs aren't broken as they work when connected to a battery.

I'm starting to wonder if I have a bad ground (or something) on the wiring harness on the car.
 
Sounds ground related. Is your trailer grounded through the frame, or does each taillight run the ground directly back to the connector with wire? Is there good continuity between the ground of the taillight sockets and the ground pin of the trailer side connector?

On the car side of the connector, is there good continuity between the ground pin in the connector and the car frame?
 
I think it's an issue with the curt wiring quick connect adapter.

I went to princess auto and bought a set of magnetic lights, and they don't work so once i get home I'll have to check the connection and the ground for the curt connector.
 
if your vehicle has amber turn signals and red brake lights or separate brake and signals, there is an electronic relay unit that combines the signals. Find it and replace it it will be part of the quick wiring adapter. I have had these burn out in the past and do the exact same thing you are describing, power but not enough current to light the bulbs.
 
Scuba Steve said:
if your vehicle has amber turn signals and red brake lights or separate brake and signals, there is an electronic relay unit that combines the signals. Find it and replace it it will be part of the quick wiring adapter. I have had these burn out in the past and do the exact same thing you are describing, power but not enough current to light the bulbs.
Click to expand...

I'll check that, I also need to check the ground and the connection at the battery.

I went back to the car with the voltmeter and I'm only reading 5 or 6 volts (although it briefly spiked to 12 volts for a very short time).

I'm hoping it is just a loose ground and is an easy fix.
 
Problem solved -- it was the ground wire.

Moved it to a better spot and everything works. Thanks for the help guys.
 
Bare metal ground, just a bolt will not cut it. Lube with vaselene each bulb base so you don't corrode in the sockets.
 
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