Trailer Taillights Not Functioning, Reading 3.5 Volts at Trailer Connector

Question:

IHi, my trailer tail lights are not working but brake/signal do work. I measure only 3.5 volts at the truck 7 pin connector tail light pin. Ground pin measures ok. Would you have any ideas what would cause the voltage ? Thanks

asked by: Colin

Helpful Expert Reply:

The typical culprit would be a dirty or damaged trailer connector. Especially if the truck is more than a few years old. Take a look at the pins in the connector. If you see any white or green corrosion on the pins, there is the potential that the corrosion has spread to the interior of the connector and is interfering with the signal from passing through the connector. The # HM40975 would make an excellent replacement.

expert reply by: Mike L