[wiener]

On my recent purchase of a 1998 K2500 I have discovered that the ABS brake system is not working. Someone took the ABS fail indicator lamp out of the instrument panel so I didn't know they didn't work. I have no computer codes on the ABS but the light is now on (working).
Some said that the front wheel sensors should read about 1500 ohms each, I tested each side and they are open. They also said if I spin the wheels by hand I should read 250mv AC I think, but I have not had a chance to try this. I seem to have power at the wire terminals, so it appears they should work. Any thoughts on this?
If anyone can steer me in the right direction, I would appreciate any help or leads. The conventional brakes work fine BTW, just no pulsing in the snow/ice on lock - up.
Thanks In Advance

 

[deepsouth]

You might try and have the dealer plug in the Tech 2 for a code. Should be a low cost deal to check.

 

[mr_udy]

Is the ABS fuse installed?

 

[wiener]

Yes I have power on the main supply connector (2 pin) and the ignition 3 circuit (10 pin) so I know there is power going to it. All fuses are good. My son in law has acsess to a tech 2 so I could go there, however he says that those coils go a lot and that is probally what is causing my lamp to be on and no ABS.
I wonder if there is a source for a less expensive aftermarket replacement if that is whats wrong?

 

[FastCR]

Just FYI there are 2 ABS fuses. One under the hood, and one in the cab. If the one in the cab is out, the cruise control won't work either.

 

[wiener]

Yup both OK. Thanks anyways.Looks like both my front wheel sensors are shot. Found a GM parts 4 less site that sells them at a discount for about $85 each. FYI
http://www.gmparts4less.com/?gclid=CJDWs5K16IkCFR-nQQodlk3oFg

 

[mr_udy]

hey..before you replace sensor...be sure the mounting pad isnt corroded. Believe it or not, this is a recall on 99 and newer GM trucks/SUVs. The smallest amount of surface corrosion lifts the sensor ever so slightly...poor/no signal. Ussually intermittent thought...ussually wont even light the ABS light. Sounds like you may have a good diagnosis...just want to maybe save you some cash for an easy check.

Pull sensor...clean mounting area....antiseeze the area and reinstall.

Good luck!

 

[wiener]

Thanks for the reply. I read about this also on another forum also.
This guy (sound like a GM service guy) had some info. Looks like the AC volt test is the best way to be sure. Mine are zero.
FYI
http://www.freeautoadvice.com/board/ubbhtml/Forum1/HTML/006656.html

 

[Spitz]

Well if both of the senors are open you wont generate anything.. Bad wheel (loose) bearings usually cause these problems.. The coil itself is very very thin wire.

 

[wiener]

Well if both of the senors are open you wont generate anything.. Bad wheel (loose) bearings usually cause these problems.. The coil itself is very very thin wire.

What happens to the sensors when the bearings start to get bad?

 

[Spitz]

The bad wheel bearing will take out the wire inside of the hubbed housing.. If it gets loose enough that is, sometimes it doesnt take a lot because the clearances arent all that far apart.