Odd wiring harness issue

Nucky

Original poster
Member
Jul 5, 2022
6
NY
I have an 08 blazer which has been locking the key in and not sending any power to the dash unless I lifted the fuze box cap, then it would start fine, recently it started doing weird electrical things and draining the battery, door lock went on and off multiple times when the ac was turned on, also the rear windshield wiper fires when ac is on, lights on the dash and such. I hunted down a bad starter relay and replaced it, worked great, a couple starts and the power train relay fried. While putting in a backup relay in a parking lot I put the power train relay in the starter assuming it was the starter that had gone bad, got nothing from the dash so accidentally brushed a wire trouble shooting it and the starter motor kicked on with the failed closed relay in. When I pull up on the battery control module wire bundle I can get the starter power so I think it's the harness or maybe bcm that's bad? There is a bolt right next to the bcm on the fuze box with a little metal tab but no nut, is that normal? I also have a worn through corrugated protector that was rubbing on some rusty pressure line but the wires look ok. Not sure what to do other than wrap the wires which might be worn and plug everything back in, the car is eating relays tho and 20 bucks a start is not cool. All the connectors look shiny new and grounds in the engine bay look okay, I think maybe there is a short but the wiring isnt bad looking, not sure what to do while I've got it apart now.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Sounds obvious but did you check the battery connections? Check the battery wires? When it happens, before doing anything else to get the power back, check for + and - at the fuse box megafuse terminals and the alternator stud. Do not use the battery as the ground or +. Check using the block and a body ground.
 
  • Like
Reactions: christo829

Nucky

Original poster
Member
Jul 5, 2022
6
NY
Sounds obvious but did you check the battery connections? Check the battery wires? When it happens, before doing anything else to get the power back, check for + and - at the fuse box megafuse terminals and the alternator stud. Do not use the battery as the ground or +. Check using the block and a body ground.
What do you mean the block?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Engine block
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
The Starter Gear is unlikely to get jammed into the Flywheel ...unless the Center of its 'platter' where it bolts up to the Crankshaft has been cracked and fractured so badly as to make the damaged outer platter holding the "Fire Ring" toothed portion...go out of round.

We HAVE had instances where this problem has occurred from time to time. The cause has been given to a severely eroded Thrust Bearing on High Mileage Engines that allows the Crankshaft to 'hunt in and out' longitudinally until the metal center of the Flex-Plate Platter finally work hardens itself to death...and Fractures completely out****:

By way of an example from a different manufacturer...but bearing similar 'ear marks' to the ones we have investigated ad nauseaum at GMT Nation:

1245610photojpg_00000073781.jpg

**** Bear in mind that even though the Center of the Flex-Plate might be completely separated... the Three Torque Converter Bolts will hold and support the Outer Platter of the Flex-Plate and even though warped out of being concentric... it will STILL allow the Crankshaft Center to "Skip & Catch" in a Shark-Tooth like fashion just enough to allow the Motor to Start... at least for a short time after the Center Lets GO Completely.


And also... as per another Thread posted by @Mooseman... Keep THIS possible problem in mind if you keep having "Mysterious Electrical Problems" that seem insolvent:

 
Last edited:

Nucky

Original poster
Member
Jul 5, 2022
6
NY
The Starter Gear is unlikely to get jammed into the Flywheel ...unless the Center of its 'platter' where it bolts up to the Crankshaft has been cracked and fractured so badly as to make the damaged outer platter holding the "Fire Ring" toothed portion...go out of round.

We HAVE had instances where this problem has occurred from time to time. The cause has been given to a severely eroded Thrust Bearing on High Mileage Engines that allows the Crankshaft to 'hunt in and out' longitudinally until the metal center of the Flex-Plate Platter finally work hardens itself to death...and Fractures completely out****:

By way of an example from a different manufacturer...but bearing similar 'ear marks' to the ones we have investigated ad nauseaum at GMT Nation:

View attachment 104248

**** Bear in mind that even though the Center of the Flex-Plate might be completely separated... the Three Torque Converter Bolts will hold and support the Outer Platter of the Flex-Plate and even though warped out of being concentric... it will STILL allow the Crankshaft Center to "Skip & Catch" in a Shark-Tooth like fashion just enough to allow the Motor to Start... at least for a short time after the Center Lets GO Completely.


And also... as per another Thread posted by @Mooseman... Keep THIS possible problem in mind if you keep having "Mysterious Electrical Problems" that seem insolvent:

It's not rodents, thanks for the info
 

Nucky

Original poster
Member
Jul 5, 2022
6
NY
It's not rodents, thanks for the info
Got it starting and the dash warnings off, seems to have been a worn wiring harness that I taped and rolled the plastic around on found it by pulling each wire apart before I tried to pull the solenoid. I'm gonna pop a new battery that isn't worn out and see if it runs reliably for a week or two. Ty for the advice.
 

Forum Statistics

Threads
23,273
Posts
637,499
Members
18,472
Latest member
MissCrutcher

Members Online