1988 Chevy Truck 4 wheel drive-A/C, heat

Tiny
RUDY910
  • 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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Friday, November 27th, 2009 AT 9:23 AM

11 Replies

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

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Friday, November 27th, 2009 AT 5:46 PM
Tiny
RUDY910
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Yea im sure my diagnosis is correct. It always blows the fuse and the 4wd dont work when that happens

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Sunday, November 29th, 2009 AT 12:23 PM
Tiny
DR LOOT
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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.

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Sunday, November 29th, 2009 AT 12:57 PM
Tiny
RUDY910
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Yea my speed ohmeter works. We finally figured it out. Thanks for the help

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Sunday, November 29th, 2009 AT 1:35 PM
Tiny
HILDY43
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How did yopu fix it I have this prob now!

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Monday, January 24th, 2011 AT 1:43 AM
Tiny
DR LOOT
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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.

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Monday, January 24th, 2011 AT 2:32 AM
Tiny
HILDY43
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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?

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Monday, January 24th, 2011 AT 3:16 AM
Tiny
HILDY43
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My truck is also a 5 speed.

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Monday, January 24th, 2011 AT 3:17 AM
Tiny
DR LOOT
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5 speed manual?

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Monday, January 24th, 2011 AT 3:45 AM
Tiny
HILDY43
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Yes

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Monday, January 24th, 2011 AT 3:54 AM
Tiny
DR LOOT
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Let me restudy the situation and I will get back to you, anything else you want to tell me go-ahead

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Monday, January 24th, 2011 AT 5:27 AM

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