Part Identification...Please

[Skyfall]

I was working on my 1991 r3500 (was 2x4, is now 4x4) and saw this item dangling down under the dashboard. It was connected with a blue and black wire in a single black connector. There are other connections on it, but they weren't connected. I tried searching for the part# and had no luck. The yellow part that sticks out slides back and forth like a variable resistor or a position indicator. If this belongs somewhere, I'd like to put it back where it came from.

Thanks in advance...

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[Danderson]

Looks like the neutral safety switch. It mounts to the top side of the steering column near the firewall.

 

[AyWoSch Motors]

Yup, neutral safety switch.

The little plastic clip that's holds it on probably broke. A few zip ties and you'll be good as new. Not really needed though, if you dont want to bother putting it back on.

 

[Skyfall]

Thank you both for your responses.

 

[Matt69olds]

I’m not all that familiar with that model year truck, so the specifics of the wiring are a bit fuzzy. The blue and black wires are a input to the pcm telling it the truck is not in park or neutral. Are those the only wires that were plug in? If so, that suggests to me the purple (start circuit) are connected somewhere under the dash.

I’m betting the switch either broke off, or is defective. Instead of fixing it the right way by replacing the switch, the previous owner just jumped the starter wires. The engine will probably crank and start in any gear, and no reverse lights.

 

[Skyfall]

Thank you. When I get it running again (I have several things disassembled right now), I will check the backup lights, etc. I have the GM service manual and complete schematics for the truck (thanks to eBay) which will be a huge help in tracing out this circuit.

 

[Scott91370]

I think starting in 85 that switch is only for reverse lights. The NSS was replaced with a column lock that will not let the key turn if the transmission is not in P or N.

 

[Matt69olds]

I think starting in 85 that switch is only for reverse lights. The NSS was replaced with a column lock that will not let the key turn if the transmission is not in P or N.

I believe you are correct, I forgot about the mechanical interlock. Forget trying to start a car that in motion

 

[Scott91370]

Forget trying to start a car that in motion

You can, it just has to be in neutral.

 

[Matt69olds]

You can, it just has to be in neutral.

I did not know that, I thought it had to bring park.