Four-wheel drive not working?

1987 GMC TRUCK
86,000 MILES
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CARTERBRENTHARRIS
  • MEMBER
  • 1 POST
My 4x4 isn’t working. It stopped working a few months ago. I found out the wires that go to the stick on the floor were unplugged under the dash. I plugged them in, and it started working again. A few weeks ago, it came unplugged again and when I plug them in again it didn’t work this time. I’ve checked the fuse it’s fine, the light on the floor turns on. I’ve checked the linkage seems fine.
Thank you for any help!
Jan 29, 2023 at 2:45 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,840 POSTS
  • ASE Certified Mechanic
I would check the wiring at the connector because it sounds like one of the terminals inside the connector has pulled out. Also use this guide to check for power and ground for the system. Here are the transfer case wiring diagrams so you can see how the system works and which wires to test.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

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Jan 30, 2023 at 10:01 AM
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