1993 GMC G3500 van: Backup lights problem

Hello everyone. My 1993 GMC G3500 van's backup/reverse lights won't come on. I've checked the fuse, the wiring (as best I could), and replaced the bulbs. I'm at a loss. The only thing I can think of is a backup sensor or switch. Where is the backup sensor or backup light switch on this vehicle? I'm guessing it's on the tranny but I'm not sure. Thanks.

-- Splat

Reply to
Splat
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Mounted on top of the steering column. Does it start in park and neutral ONLY? If you move the lever do the lights come on in a different gear?

Reply to
Steve W.

Yes, the van will only start in park or neutral. BTW, it's a diesel if that matters. No, the lights do not come on at all, even if I run thru the gears.

-- Splat

Steve W. wrote:

Reply to
Splat

Nope the diesels still used the same trans as the gassers at that time. If you look on top of the steering column behind the dash you will find the switch and it's wiring. You are looking for a dark blue wire that feeds it power from the fuse and the wire that should have power when in reverse is light green. If you have power on those wires when in reverse, the problem is likely in the harness somewhere. The wiring to the rear should be light green as well.

Reply to
Steve W.

Yep, light green with no stripe is the one. I tried tracing it under the dash but... well, you know how that goes. I'll check the steering column behind the dash then tomorrow. Thank you for your help and time, Steve.

Reply to
Splat

Steve, it was the switch under the dash. It had moved and was off position. I played around with it until the reverse lights went on only when tranny was actually in reverse. Fixed. Thank you again for your help.

Reply to
Splat

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