First Post Seat belt dash light issue

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vetmph

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Oct 18, 2024
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Location
pennsylvania
First Name
paul
Truck Year
1987
Truck Model
1500
Engine Size
305
My seat belt buzzer works fine in my 1987 GMC it goes off when the seat belt is fastened but the dash light does not go off. My temporary solution is to remove the bulb form the panel but I would like the system to work. The key and headlight buzzer works as well it is just the light won’t go off for the seat belt and also the light for the parking brake won’t go off either. I know they are separate circuits but wondering if it could be an issue on the dash circuit board?
 

Jgonick

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West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
The parking light comes on when tan-33 wire (going to circuit board) is grounded. It can ground at one of two locations. It is grounded by the switch at the parking brake & brake proportioning valve (usually on frame under radiator) - Make sure the tan wire isn't grounding out at those locations or on it's way there.


I believe the seat belt light illuminates when yellow-237 wire is given power by the alarm module. On an 87, that wire should come from the convenience center and head to the circuit panel. Not sure why it would remain on, maybe a bad alarm (buzzer) module- You could pull out the module and see if the light goes out.

Attachments show where the parking brake switch is & what the proportioning valve will basically look like.
 

Attachments

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    propvalve.jpg
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  • brakeswitch.jpg
    brakeswitch.jpg
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Last edited:

NC81c10

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Aug 11, 2025
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Location
North Carolina
First Name
Brian
Truck Year
1981
Truck Model
c10
Engine Size
350
I'm having the same issue on my 81. My seat belt light stays on all the time. I have thought about wiring in a timer for it to cut off after 10-20 sec. I would also like it to work and not just pull the bulb. I did find the alarm was unplugged. Plugged it up and works when pull seat belt out but light stayed on.
 

ali_c20

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Location
Austria
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Alexander
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1974, 1979
Truck Model
C20, K5
Engine Size
350, 350
Welcome from Austria. The fun of finding electrical issues.
 

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