Repairing car ABS module

[mrmarcdee]

I would like some electronically minded people's opinion on this before I proceed. I am attempting to repair the circuit board of a car's (chevy s10 pickup) ABS module. The most common fix is to simply heat and reflow a couple of the solder points. This did not work for me unfortuntely. The ABS pump motor runs continuously when the fuse is inserted.

This link http://www.justanswer.com/chevy/4zypn-chevrolet-s10-abs-light-getting-humming.html says "the problem is the internal relay ... is shorted"

And then on this forum topic http://www.chevytalk.org/fusionbb/showtopic.php?tid/118812/ one guy says:

"I don't think its a relay that breaks,it's a transistor

How to replace
When you look at the control board, you have your 12V input and 12V out to
the small motor. The MOSFET is the larger one close to this 12V out. The
one that was in mine was a Philips BUK9608. I replaced it with an
International Rectifier IRL2505S. You can order them form DigiKey.compart
number IRL2505S-ND.

Replacing it is the easy part, its getting to this guy that is hard part.
From the factory, the circuit board is dropped in the housing and then
soldered in. So you will have to unsolder the 12V power pins, the 12V power
pins out to motor, and the sensor connector pins (about 10-12 pin connector)
before you can remove the circuit board from the housing.

If you go through all this effort to fix the problem, do yourself a favor
and solder a diode across the "12V out to the small motor" (like a
FR302DICT-ND from DigiKey) to protect the MOSFET (band towards the positive
side)."​

So I have desoldered and disconnected this board to see the underside. I have found the MOSFET in question, shown by the pen here https://www.dropbox.com/s/9lfvl48wi0ig27v/20150612_213306.jpg?dl=0, and closeups here https://www.dropbox.com/s/tpgea9v5hx7246s/20150612_213314.jpg?dl=0 and here https://www.dropbox.com/s/h4gz3qosf6taput/20150612_213347.jpg?dl=0. And this is the part he says to replace with http://www.digikey.com/product-search/en?vendor=0&keywords=IRL2505S-ND.

So my question I guess is: does that part look bad in any way? And what and where is the relay?

Thanks for any help. Let me know if I need to take better pictures.

 

[mrmarcdee]

So the biggest black thing is the power relay (I always think of things to search for after I post a thread...). It is slightly swollen/squishy on the two longest sides, but barely.

 

[mrmarcdee]

I just ordered these two parts.
http://www.mouser.com/Search/Produc...V-5virtualkey66710000virtualkey769-JSM1-12V-5
http://www.mouser.com/Search/Produc...BFvirtualkey57370000virtualkey942-IRL2505SPBF
Hope they're right.

 

[davenn]

cant help you too much on that one

let us know how you get on when the parts arrive

 

[mrmarcdee]

Got those two parts replaced on the board and everything put back together and in the car. The ABS pump motor no longer runs continuously, and the ABS dash light sometimes turns off. Until it realizes there is another problem with the wheel speed sensor and it sometimes activates the ABS during normal braking. So I think my repair worked, just need to fix this other thing, which isn't an electronics problem.