Low voltage at reverser light

[Eric Palmer]

I have a 1998 Patriot Brandywine and the right reverse light won't light up and when I put a voltmeter to the terminal inside the socket, it shows 6.5 volts while the other reverse light socket shows 12+volts. I'm currently thinking I'll have to trace the wires back to where they originate and check each (if any) splices along the way to see if there are the problem. I was also gonna check the main power distribution panel below the driver side window and make sure the voltage is correct there first. Any suggestions would be appreciated as I'm hoping to head south this week from Ontario.
Thanks.
Eric

[Steve Huber Co-Admin]

Eric,
Suggest you first use a pin or other sharp probe to pierce wire insulation at reverse light terminals to see if you have 12V there. It's possible that corrosion has gotten into the terminal lugs, resulting in high resistance. Also check the connector in the rear (check voltage on wires same way) where the line from the electrical bay terminal branches out to feed the 2 backup lights. If one light is OK, the problem has to be between that connector and the bad light socket since there should be only a single wire coming from a terminal in the electrical bay to the rear of the coach.
Steve

[Eric Palmer]

Thanks Steve. Turns out I am getting 12+volts when I bypass the ground and ground to something else. So a bad ground is the problem.

[Joel Ashley]

Moisture intrusion in exterior fixtures is the common cause of corrosion and the resulting resistance at connections, ground or hot.  Cleaning and/or reattaching wire connections and contact points is a frequent task on RV’s. 

To help reduce that frequency, try bulb grease on contact points during reassembly, and Corrosion-X on assembled exposed metal connections afterward.

Joel