Blows PCM fuse when ignition turned to on

Tiny
DIRK ELKINS
  • MEMBER
  • 1994 CHEVROLET S-10
  • 4.3L
  • V6
  • 2WD
  • MANUAL
  • 160,000 MILES
Was working fine set for about an hour when to start it would not start. Unhooked ECM and it does not blow the fuse.
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Wednesday, March 15th, 2017 AT 6:44 PM

6 Replies

Tiny
CARADIODOC
  • EXPERT
A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a twelve volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it is not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.
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Wednesday, March 15th, 2017 AT 6:53 PM
Tiny
STEVE W.
  • EXPERT
You have the VCM on the right inner fender correct? If you disconnect it and the fuse does not blow I suspect the VCM is bad. However, you could unplug the injectors and see if it still blows, they are also powered from that fuse.
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Wednesday, March 15th, 2017 AT 7:30 PM
Tiny
DIRK ELKINS
  • MEMBER
?Vcm
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Wednesday, March 15th, 2017 AT 7:59 PM
Tiny
DIRK ELKINS
  • MEMBER
Lol.
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Wednesday, March 15th, 2017 AT 8:29 PM
Tiny
DIRK ELKINS
  • MEMBER
Thanks, I will try this in morning. If does not fix issue I will be asking for more help.
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Wednesday, March 15th, 2017 AT 8:30 PM
Tiny
STEVE W.
  • EXPERT
GM used a Vehicle Control Module on the manual gearbox S-10s until they switched to full OBDII in 1996. They used a Power-train Control Module on the Automatics. Two different units with different wiring and locations. The VCM is on the inner fender under the hood. The PCM is behind the instrument panel inside the vehicle.
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Thursday, March 16th, 2017 AT 1:03 AM

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