Question about 2003 Chevrolet Avalanche

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Blown fuse pcm

My pcm fuse blows when i turn on the ignition but if i take out the fuel relay switch the pcm fuse does not blow what could be the problem

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  • Chevrolet Master
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It is possible that the fuel relay is faulty and causing excessive current through the pcm fuse which is blowing because of the excessive current draw to the relay.

Posted on Mar 28, 2014

  • Brett Cirbo Mar 29, 2014

    First, begin with the basics. Shut EVERYTHING that is un-necessary, OFF. Install a new PCM fuse and then turn the ignition on to the RUN position. Does the fuel pump activate and charge the system? If it does, and the fuse has yet to blow, then the fuel pump can be eliminated as a power drain or short. // If the fuse did blow, then look towards the ignition switch to start. GM is not famous for good quality ignition parts. Disconnect the primary connector to the ignition module and try again. This should differentiate between the ignition switch and the ignition module. A fuel pump failure is possible, but highly unlikely. I would suspect the ignition or a bad ground before a fuel pump failure.

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check the crankshaft sensor

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SOURCE: no power to ignition 96 camero dl

Check the wires to the distributer or to the modules could be poor or no conection. If you can turn the car over but no spark it's probably something to do with ignition, distributer, module, or wiring to the ignition.

Posted on Jan 25, 2009

a00gha
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SOURCE: blowing ignition a fuse

I believe you mean a 40 amp fuse? Wow! that's a dead short somewhere on a large wire. Could be difficult, or hopefully easy to find. There's always the smoke test option: Solder a jumper wire across the top of the fuse, making the circuit essentially un-fused and look for the smoke. Not the best method, but quick. Warning: if you do this, depending on where the short is, you could melt down the wire harness or possibly start a fire. Try this at your own risk! IT'S A "LAST RESORT" THING, WHEN YOU'VE TRIED EVERYTHING ELSE AND FAILED! Good luck.

Posted on May 25, 2009

gypsycat00
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SOURCE: 94 chevy s10 blowing fuse

Chances are, you have a short somewhere in the wiring that is causing too much amperage to pass through the fuse causing it to blow. Use a decent voltmeter that will show opens and shorts to test continuity with the wires that run to the ignition.

Posted on Jul 11, 2009

  • 10 Answers

SOURCE: fuel injecter fuse blow imeditaly when ignition turn on

sounds like a short in the wiring from the fuse and the fuel injector junction block. GM like most fuel injection systems control injector firing by the computer providing ground to each injector in pairs or individually. The fuel injector fuse provides power to the injectors using splices therefore enabling one wire to feed 6 injectors. A shorted wire at any of these wires will blow the fuse. On one rare incident I found a faulty computer caused the fuse to blow. A shorted injector will just cause a rough running problem due to the injector stuck either open or closed.

Posted on Aug 05, 2009

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