What would cause the ECM b fuse to continuously blow?

Tiny
TRAVISB88
  • MEMBER
  • 1991 GMC SIERRA
  • 202,000 MILES
Already checked the fuel pump, fuel selector valve, throttle position sensor, and the harnesses pertaining to these things for shorts and found nothing.
Saturday, August 27th, 2011 AT 4:13 AM

3 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
You have short circuit direct to ground from the component/wiring that the ECM B fuse powers
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Monday, August 29th, 2011 AT 12:07 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,916 POSTS
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 12 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's 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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Monday, August 29th, 2011 AT 1:32 AM
Tiny
RASMATAZ
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Doc -Old school technique-Very good, Have a nice Sunday
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Monday, August 29th, 2011 AT 1:35 AM

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