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f.monroe · 02-04-2011, 12:21 AM

Sounds like the wires are shorted somewhere at the back of the cab or you have a shorted bulb. The lights come on when the switch or door pins send a ground signal . My dads 86 had a wire that chafed on the inside of the cab and it was fun to find. I ran a new wire up the driver side of the cab and attached it at the dome light replacing the factory wire . Problem solved. I have also seen bad bulbs allow the 12v signal to seek ground through the bulb . It acted like a resistor and was dim just as yours are. When you opened the door or switched the light switch, it came on bright because of the good ground.
Frank

02-04-2011, 12:21 AM	#10
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Re: Problem with courtesy lights Sounds like the wires are shorted somewhere at the back of the cab or you have a shorted bulb. The lights come on when the switch or door pins send a ground signal . My dads 86 had a wire that chafed on the inside of the cab and it was fun to find. I ran a new wire up the driver side of the cab and attached it at the dome light replacing the factory wire . Problem solved. I have also seen bad bulbs allow the 12v signal to seek ground through the bulb . It acted like a resistor and was dim just as yours are. When you opened the door or switched the light switch, it came on bright because of the good ground. Frank __________________ Born and proudly residing in a Red State !