ABS light and fried alternator linked?

[Tinstar]

M925A2
All stock
TMs checked and search done as best as possible.

Truck has been flawless for three years.
Just parked it two days before with M989A1 still hooked up to it.

Went to start it today and didn't get the ABS self check clicks and light remained illuminated. Thats weird.....
Started truck and ran for a couple minutes. Voltmeter in green.
Smelled something electrical getting hot.
Few seconds after that some light smoke in cab.
Shut off truck and battery switch.

Reached under dash and felt all the wires. Nothing hot.
Get out of truck and could smelling something that had gotten hot but couldn't see anything with hood open. Was coming from engine compartment.
Climb under truck and check the ABS wiring. All looks ok.
Checked PCB connection and was good.
Checked all wiring under hood and didn't see anything odd.

Brother shows up and looks also.
Coukd not tell where smell was coming from.

Ok. So. Hood up. Engine start.
Voltmeter in yellow this time and smoke coming off alternator.
According to brother the smoke was coming from underneath the wire cover at
the back of it.
Yep. Smell really bad and obvious signs of toasted wires.
Removed alternator to take to rebuild shop tomorrow.


Finally.....My question is:
Did the alternator failing cause the ABS light to stay on?
or Did the ABS system somehow cause the alternator to fry?
Possible two separate issues and just bad timing?

Truck starts fine and has been almost trouble free except a PCB that was acting up before it was replaced about a month ago.
Batterys all check out and load test good.
Lights all work, including trailer.

Ideas?

 

[lindsey97]

Voltage regulator.

Did you replace the pcb with new or used?

Voltage fluctuation, or low/bad batteries will fool with the abs function.

 

[Tinstar]

The PCB was replaced with New.
Rebuilding original for spare.

So the VR can trip that light?

 

[Jakelc15]

I think your PCB senses the truck running from the alternator charge circuit. Could be tricking your abs

 

[Tinstar]

I couldn't find anything in the troubleshooting for this particular issue.
Should I check anything particular before going live with the rebuilt alternator?

Followed and checked visually all the ABS wires under truck.
Didn't find any chafing or formally hot wires.
All was nice and tight.

I did use a DVM to check battery's before load testing.
All was where it is supposed to be.

 

[Jakelc15]

You could turn the power back on and see if your abs does the check again. Make sure your loose alt wires aren't touching anything

 

[Tinstar]

Actually tried that.
Taped up wire ends so they wouldn't contact anything.
Turned on battery and run switch.

ABS light stays on and no self test noise.
I did not start it of course.

 

[Jakelc15]

Fuses under dash good? Might have a abs controller problem

 

[Jakelc15]

http://www.steelsoldiers.com/showthread.php?151417-Abs-fuse-quot-BLOWS-quot

 

[Tinstar]

Fuses under dash good? Might have a abs controller problem

Have to admit I haven't checked yet.
Was trying to figure the alternator and ABS light thing and totally spaced about the fuses.
Will do that tomorrow

 

[Tinstar]

http://www.steelsoldiers.com/showthread.php?151417-Abs-fuse-quot-BLOWS-quot

Nicely done.
Thank you.

My search skills obviously suck

 

[lindsey97]

Check and clean your grounds.

 

[Tinstar]

Check and clean your grounds.

Already in the works.

 

[simp5782]

Did you unplug the trailer? And then retry it. My m322 trailer has ABS and my the abs light in my one m923.

I had no luck finding a good rebuild kit for the stock one. Just buy Clint's upgraded alternator.

Sent from my SM-G860P using Tapatalk

 

[Tinstar]

Reading some old threads, it sounds like the alternator may have spiked the ABS ECU with too much voltage.

Before I replaced the PCB, it would act up and for very short moments, put the VM in the red before I shut off truck.

Never Seemed like it was affected since it worked like usual. ......til now.

 

[simp5782]

Did you unplug the trailer? And then retry it. My m322 trailer has ABS and my the abs light in my one m923.

I had no luck finding a good rebuild kit for the stock one. Just buy Clint's upgraded alternator.

Sent from my SM-G860P using Tapatalk

My abs light gets tripped by the trailer abs but not its self check. I thought the socket just added power to it but the pcb must sense it

Sent from my SM-G860P using Tapatalk

 

[Tinstar]

Did you unplug the trailer? And then retry it. My m322 trailer has ABS and my the abs light in my one m923.

I had no luck finding a good rebuild kit for the stock one. Just buy Clint's upgraded alternator.

Sent from my SM-G860P using Tapatalk

I did not.
M989A1 doesn't have ABS that I'm aware of.
But will of course try that.

Ran out of sunlight so obviously didn't get to check several things.

 

[Tinstar]

My abs light gets tripped by the trailer abs but not its self check. I thought the socket just added power to it but the pcb must sense it

Sent from my SM-G860P using Tapatalk

Ok
will check that first thing !!

 

[infidel got me]

Buy the alternator from 74m-- less headache and your problems are over. Go ahead and get a used/new abs module cause yours is fried.

 

[Tinstar]

Ok
Just back from alternator rebuild guy.
Whole thing is toast. Not just the regulator.

Now I need a brand new alternator and sounds like maybe ABS module.
Will still check ABS fuses and such.
I might get lucky.........