Major electrial problem! Need help!!
Thread Starter
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Fleet Mechanic
Joined: Dec 2007
Posts: 1,766
Likes: 8
From: Hutchinson, KS
Major electrial problem! Need help!!
Problem is on my 96. I replaced the alternator today and was an idiot by not disconnecting the batteries. When reinstalling the alt, it caught the wiring harness and the power wire came in contact with the alt case causing a spark for a slit second.
Finished install then went to start it up. Turned the key on and all the normal dash lights appreared, but within a second or 2, everything went dead. No lights, no door dinging, nothing. Tried several times with the exact same results. Disconnected batteries for about 5 minutes and tried again. Things seemed fine when turned key on again. But this time about 10 seconds, I heard a click and everything went dead and that time for good. No fused are blown.
Since I have another pickup parked next to it in the shop right now that runs fine, I swapped all the relays I could find. Changed pcm's, as well as the relay on the pass fender. There's no changes at all.
I'm not sure what is freakin' going on!!!!
It's like the batteries are completely disconnected. Need help fast as I need the truck going again in a couple of days.
Finished install then went to start it up. Turned the key on and all the normal dash lights appreared, but within a second or 2, everything went dead. No lights, no door dinging, nothing. Tried several times with the exact same results. Disconnected batteries for about 5 minutes and tried again. Things seemed fine when turned key on again. But this time about 10 seconds, I heard a click and everything went dead and that time for good. No fused are blown.
Since I have another pickup parked next to it in the shop right now that runs fine, I swapped all the relays I could find. Changed pcm's, as well as the relay on the pass fender. There's no changes at all.
I'm not sure what is freakin' going on!!!!
It's like the batteries are completely disconnected. Need help fast as I need the truck going again in a couple of days.
Thread Starter
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Fleet Mechanic
Joined: Dec 2007
Posts: 1,766
Likes: 8
From: Hutchinson, KS
Is it an inline fuse? I've given up for tonight and going to hit it early in the morning. It must be in the wire loom where the 2 grey wires come together?
Fleet Mechanic
Joined: Aug 2007
Posts: 1,508
Likes: 2
From: The boonies by Dallas OR
The two gray wires are a pair of 12 gauge fusible wire. They go about 4-6 inches into the loom and then are spliced into the 6 gauge wire going the rest of the way to the alternator.
There are three sets of links on our trucks. All three are twin 12 gauge links that are spliced into large wire a short distance into the loom. One set goes to the alternator, one goes to the glow plugs and the third goes around the front of the radiator and over to the engine bay fuse box.
Fusible wire uses really high temperature insulation so the insulation stays intact when the metal vaporizes inside. If they blow there often isn't anything visible on the outside so make sure to check with a meter. I'd focus on the right battery to starter solenoid wire. Shorting the alternator should blow the alternator fusible link but leave everything else working. Since everything went dead, I'd suspect the wire between the battery and solenoid was damaged when you shorted the wire, and then when the PCM kicked in the glow plugs, the demand burned the wire open.
There are three sets of links on our trucks. All three are twin 12 gauge links that are spliced into large wire a short distance into the loom. One set goes to the alternator, one goes to the glow plugs and the third goes around the front of the radiator and over to the engine bay fuse box.
Fusible wire uses really high temperature insulation so the insulation stays intact when the metal vaporizes inside. If they blow there often isn't anything visible on the outside so make sure to check with a meter. I'd focus on the right battery to starter solenoid wire. Shorting the alternator should blow the alternator fusible link but leave everything else working. Since everything went dead, I'd suspect the wire between the battery and solenoid was damaged when you shorted the wire, and then when the PCM kicked in the glow plugs, the demand burned the wire open.
Thread Starter
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Fleet Mechanic
Joined: Dec 2007
Posts: 1,766
Likes: 8
From: Hutchinson, KS
Joe, thanks a bunch for the info on the fused links! Helped a ton. Checked all them with a meter and they're all fine.
Madpogue- for most the obvious choice would be to check the batteries with a voltmeter. But I'm not very good with one and don't use it all that often, so unless it's in front of me, I typically don't think of it! As for checking voltage with it running - there's no juice anywhere even get the truck running.
I did find out tonight after using the meter as well as a test probe light, that the battery lead to the starter relay wasn't working very well. Barely light the light. Got to looking at it, and it was full of corrosion in the insulation right at the battery terminal connection. Moved it around and the insulation cracked out and not very many of the wire strands were still together. I'm guessing that this is why there was no power anywhere. Gonna get it fixed tomorrow and see how it goes.
I'll keep everyone up to date.
Madpogue- for most the obvious choice would be to check the batteries with a voltmeter. But I'm not very good with one and don't use it all that often, so unless it's in front of me, I typically don't think of it! As for checking voltage with it running - there's no juice anywhere even get the truck running.
I did find out tonight after using the meter as well as a test probe light, that the battery lead to the starter relay wasn't working very well. Barely light the light. Got to looking at it, and it was full of corrosion in the insulation right at the battery terminal connection. Moved it around and the insulation cracked out and not very many of the wire strands were still together. I'm guessing that this is why there was no power anywhere. Gonna get it fixed tomorrow and see how it goes.
I'll keep everyone up to date.
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
D'OH, my bad - confused this thread with another where the OP got the truck running, but it stalled a few feet down the road. Disregard!
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Thread Starter
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Fleet Mechanic
Joined: Dec 2007
Posts: 1,766
Likes: 8
From: Hutchinson, KS
Put in all new positive cables last night. That corroded battery lead to the starter relay was the issue. So now I've got juice again. Checked with the voltmeter across all the components and it's working good.
No just need to figure out my hard start issue cause the low batteries/juice has been masking it.
No just need to figure out my hard start issue cause the low batteries/juice has been masking it.
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