2001 Chevrolet Blazer ECM fuse keeps blowing

Tiny
SIGNMAN1
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 4.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
Ecm fuse keeps blowing. Just had tune up, cap rotor, wires coil, and plugs. Fuse still blows happened again mechanic says fuel pump, new fuel pump still blows. Changed altenator. Still blowing fuse, sometimes a few hours, even a few days before it blows. Now seems to be occurring quite often. At wits end what do you suggest. Spending a lot of money and not fixing problem. I am attempting to find problem myself, as the mechanic has not found the problem. Thanks for your input in this matter. Signman.
Saturday, August 1st, 2015 AT 10:38 AM

3 Replies

Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
If you have already had a mechanic look at it, I'm not sure how to help? Is this the ecm 1 fuse--15 amp? Does it blow as soon as you turn on the key, or does it blow intermittently? Intermittent problems can be hard to track, you have to test when problem is ongoing, otherwise it's just a guess. If it blows quickly, you might be able to disconnect/reconnect everything on that fuse circuit one at a time, see if anything shows up? You could check amp draw on the different components, add it up?

It might be just a wiring circuit or it could be a component? Trouble codes, live engine data, doesn't show anything?
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Saturday, August 1st, 2015 AT 11:36 AM
Tiny
SIGNMAN1
  • MEMBER
  • 2 POSTS
It is the ecm B fuse 20 amp. What is happening now. The fuse has blown, I replace it, it sparks and blows on contact with key out of ignition. I traced wires that are connected to that fuse, they run from fuse panel down along frame, branch off to transmission, and back to fuel pump. I see no breaks or disconnects along the run back to the gas tank at this point I stopped. Could the wires to the fuel pumpconnction have come apart and are now touching metal causing this fuse to blow immediately on contact.

Again Thanks for your help.
Signman.
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Saturday, August 1st, 2015 AT 6:53 PM
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
My info shows that fuse also supplies voltage to the pcm as well as fuel pump relay. So, unplug both the pcm and fuel pump relay and see if the fuse still blows? If it does, you have a faulty wiring circuit or something wrong with fuse box. That fuse circuit, is hot all the time.
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Sunday, August 2nd, 2015 AT 10:08 AM

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