Mechanics

CHEVY 4 WHEEL DRIVE-A/C,HEAT

1988 Chevrolet Truck

Transmission problem
1988 Chevy Truck V8 Four Wheel Drive Automatic 150000 miles

when u shift 2 4wheeldrive it blows the fuse for a/c, heat
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Rudy910
November 27, 2009.



You got me, I have never heard of that problem, are you sure your diagnosis is correct?

Dr Loot
Nov 27, 2009.
Yea im sure my diagnosis is correct. It always blows the fuse and the 4wd dont work when that happens

Tiny
Rudy910
Nov 29, 2009.
I am sorry you are correct, I was checking the wiring diagram on your truck, the AC/Heater fuse is connected to the trans-case, it get its power Supply from the speedo fuse, my question now is, dose your speedometer work? If it does. Most likely it is this which in the transfer case, that is grounded in other words, it is no good. Because every time you put the transfer case in 4 Wheel Drive. The fuse blows.

Dr Loot
Nov 29, 2009.
Yea my speed ohmeter works. We finally figured it out. Thanks for the help

Tiny
Rudy910
Nov 29, 2009.
How did yopu fix it I have this prob now!

Tiny
Hildy43
Jan 24, 2011.
Replaced (VSS) on the back upper side of transfer case, make sure you wiring harness is not damaged. Let me know if you need anything else.

Dr Loot
Jan 24, 2011.
What is a vss? When I unpluge the indicator light from under the truck my heat works fine but I dont think I have 4x4 yet?

Tiny
Hildy43
Jan 24, 2011.
My truck is also a 5 speed.

Tiny
Hildy43
Jan 24, 2011.
5 speed manual?

Dr Loot
Jan 24, 2011.
Yes

Tiny
Hildy43
Jan 24, 2011.
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