Reverse Light Mystery

[ssgtcampbell77]

I hate to have to start a thread about a freakin reverse light but Im stumped and nothing on here or the TMs have helped. My 85 M1008 had the driver side reverse light out when I bought it. After finally getting around to investigating I found that the whole plug w/ pigtail (with to wires - green and black) was missing. So I went to the parts stores and was told nobody carried the two wire pigtails. So I got the 3 wire w/ a black, yellow and brown wire. I hooked the black to the ground and the yellow to the hot. I now have two good reverse lights but ZERO rear lights (except headlights). No running lights, no blinkers, no markers in the front, no brake lights. I disconnected the plug and still no lights. Checked fuses, all good. Gave up for the night. Came in this morning, all lights operational except the reverse which I disconnected. Reinstalled the plug, got reverse lights, ZERO other lights (except headlights).

 

[Warthog]

Liar, Liar, Pants on Fire...............


They do make the 2 wire pigtails, you just have to order them.

LMC, 1973-1987 Truck Manual, Page 179, Item 36-0415 - $9.95.

I am looking at the wiring diagrams to see why/how all the lights went out.

 

[ssgtcampbell77]

Thank you, I can't believe I didn't see that. I was on their website yesterday too. Ive followed the schematics and checked everything back to the fuse box. Because it comes and goes like that and because the reverse lights share the same fuse (I think) Im going to check to see if the fuse holder itself isnt loose or corroded. Thanks for your help WH.

 

[ssgtcampbell77]

Actually, I guess that wouldnt make sense either as when I put the reverse light in and put the truck in reverse, I had reverse light but it caused the rest to go out.

 

[ssgtcampbell77]

Found my problem, there was a short in the wiring that went to the driver side reverse light.

 

[doghead]

Where was the short and what caused it?

 

[WARWAG]

I had a little electrical Gremlin as well with my pass front running light. Picked up a new bulb pack and proceeded to remove the head light grill and turn signal running light housing. Turns out the old bulb was just fine. After a few minutes of playing with the 3 wire bulb housing the running light came on. Turns out the connector was in need of cleaning. While I was at it I replaced both headlights. I cleaned the connector contacts and then filled them with Dielectric grease. The new headlights contact I coated in Amsoil MP3 then installed (same with running light contacts). The moral of this story is clean and protect your electrical connectors when your there. If theres a problem try that first. Not sure who said it but has been said "If it electrical clean it if its rubber replace it." Or something like that. Wise words indeed. Glad you found the problem.

 

[ssgtcampbell77]

The short was on the light green wire connected to the reverse light housing. It had frayed and was grounding out on the body behind the light housing. I had removed both sides, replace all bulbs and cleaned all the connections. I was still getting power from that wire but it was because I was pulling the wire out and testing it. As soon as I would put it back in, it would rest back against the body shorting it. It was far enough back on the line that I had to go up from underneath to see it and even then it was hard to see as it was barely more than a crack in the casing.