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40 amp IGN A fuse blowing

167 Views 4 Replies 3 Participants Last post by  RGerard
1995 6.5 Silverado dually.

Mid-crank truck stopped. No gauge response, no bell for key insert, no crank sound/action when turning key.

IGN A 40amp fuse was blown. Replaced with 40A from brakes, bell sounded for key, gauges lit up, glow plugs, etc. Turned key, no crank sound, just blew fuse immediately.

Similar thing happened a couple of weeks ago, just a dead key turn (no crank, no sound etc) but gauges were responsive and fuse did not blow. Just figured battery cables loose and tightened/wiggled and truck started. Not sure if this is related.

Waiting to get a tow currently. What should I be looking for as far as diagnosing? Does ignition switch or starter seem to be on right track and is there a way to eliminate easily? Was going to see if just corrosion inside the fuse box.
Jumper wire will get gauges to work again and bell to ding but will not crank.

Any ideas or insight would be appreciated as always.
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1995 6.5 Silverado dually.

Mid-crank truck stopped. No gauge response, no bell for key insert, no crank sound/action when turning key.

IGN A 40amp fuse was blown. Replaced with 40A from brakes, bell sounded for key, gauges lit up, glow plugs, etc. Turned key, no crank sound, just blew fuse immediately.

Similar thing happened a couple of weeks ago, just a dead key turn (no crank, no sound etc) but gauges were responsive and fuse did not blow. Just figured battery cables loose and tightened/wiggled and truck started. Not sure if this is related.

Waiting to get a tow currently. What should I be looking for as far as diagnosing? Does ignition switch or starter seem to be on right track and is there a way to eliminate easily? Was going to see if just corrosion inside the fuse box.
Jumper wire will get gauges to work again and bell to ding but will not crank.

Any ideas or insight would be appreciated as always.
Try unplugging the Fuel Filter heater and WIF sensor on the side of the filter manager and see if things improve
The starter is the only thing on that 40A fuse that is not individually fused down circuit.
Check the starter solenoid wire (heavy purple wire) from the back of the engine down to the starter.
They have shorted to various things back there. Find your short before the ignition switch melts down.
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Will check into all those things tomorrow morning. Thanks for the leads guys. Will be sure to update.
All right, does look like it is the solenoid wire. I am still trying to find its path since everything is in the way. Was able to get a little space worked around wire and get it off the exhaust and the glow plug heat shield. Using jumper wire again truck cranked and started with both the FFM wiring connected and disconnected so the short seems to be contained to that solenoid wire. (still need to get into town to get some fuses, but at least on right track). I did see on the schematic as mentioned that the 40A circuit seems to only include the starter solenoid, starter motor, gear selectior switch, and the ignition switch. Lines up with why the little light for the gear indicator on dash would not even light up.

Hoping I can get a clearer view of wire to see if I can repair or just slide a hose around it to protect it. I had placed the larger power cable from battery into a larger rubber hose years back when I replaced that cable and don't know why I didn't think of doing the same for that solenoid wire. Come to think about it, I think that larger cable had melted and blown the same fuse, thus prompting me to protecting it with the hose during replacement.

Thanks again for the help guys. Came through again. Very much appreciated.
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