Abs fuse "BLOWS".

[machinist75]

Doing some work on the 923 today and decided to install my spare pcb box hoping it would solve the abs light being on at all times. Got it on, flipped the switch and still the light was on. Crawled under the dash, which isn't an easy chore, and fracked down the fuse holders. First I found the 3 amp fuse, still good. Next after about 10 mins of searching I found the 15 amp fuse. Pulled it out and it was blown. Installed a new one and flipped the switch, popped again. Anyone with greater knowledge than me have any ideas of what the problem could be. I looked around and the grounds that I could find and they looked fine. Any help would be apreciated.

 

[Bandit02]

There is a short somewhere in the ABS circuit.

Is there a schematic of the ABS system in the TM?

 

[Monkeyboyarmy]

Most likely the abs control unit is bad. There is a diode in it that fails to a shorted circuit if there is an over-voltage condition. Between the rear axles, you will see the "black box" . Unplug the connector and try your fuse again. If the fuse doesn't blow, you know where your problem is at.

 

[machinist75]

Most likely the abs control unit is bad. There is a diode in it that fails to a shorted circuit if there is an over-voltage condition. Between the rear axles, you will see the "black box" . Unplug the connector and try your fuse again. If the fuse doesn't blow, you know where your problem is at.

Thats a good idea, thanks. I'll try that out.

 

[wheelspinner]

Also if I remember correctly, that ABS harness grounds through the PCB mounting tabs. I had one that had paint on the spacers and prevented a clean ground.

 

[profo]

I had the same problem on mine found two things wrong the ABS ran off of 12 volts so the positive went to the middle jump terminal on the batteries and the module over the axle was shorted also blowning the fuse.

Marty

 

[machinist75]

I had the same problem on mine found two things wrong the ABS ran off of 12 volts so the positive went to the middle jump terminal on the batteries and the module over the axle was shorted also blowning the fuse.

Marty

So your saying the module is 12 volt?

 

[profo]

So your saying the module is 12 volt?

Thats how it came from government when i got truck.!

 

[M35A2-AZ]

The ABS should be running on 24v not 12v, The heater wire is hooked up to 12v. Check the wire markers. The ABS wires may not be labeled.

 

[machinist75]

The ABS should be running on 24v not 12v, The heater wire is hooked up to 12v. Check the wire markers. The ABS wires may not be labeled.

Thats what I thought, thanks for reafirming that.

 

[juanprado]

p2p diagram

 

[Mike929]

Thanks, I never could get that maintenance software to run.

 

[machinist75]

I unplugged the abs module (that thing is a pain in the arse to get too) and replaced the blown fuse again. Climbed back up in the cab and flipped the switch and the fuse didn't blow. So I'll be ordering a new abs module from the classifieds. When I get it in and plugged up I will update the results.

 

[machinist75]

Replaced the abs module with a used one I Purchased from M35a2-AZ. Plugged it in, flipped the switch, abs light on, double click, then light off. Problem fixed. Thanks for all the input, another reason I love this site and am greatfull for all the good people here. I love it when a plan comes together.

https://m.youtube.com/watch?v=XwozVKOkzz4

 

[M35A2-AZ]

Glad you got it going!!!