Hi,
I have an 87 corvette convertible that lights the abs light only when it is raining. I have been checking the wheel sensors and get the same resistance when it is raining or not. Also none of the connectors at each of the sensors look wet. Can someone please tell me:

1) Has anyone experienced this? Can it be a wheel sensor?

2) Is there a connector on the wiring harness where it enters into the car or is that just a sealed pass through?

3) Can a newer abs module (one that gives diagnostic codes) be installed?
It would make finding these intermittent problems much easier.

Thanks,
Mark

 

Interesting,

I've never experienced this particular problem but have experience with ABS. It could be a wheel sensor.

The main harness connectors are in the well behind the drivers seat. I would inspect that area first.

Almost positive the newer modules(90 and above) will not work on 86-89 cars. Am pretty sure its a wiring thing. The 86-89 will hook up to a 90, but not work, cause I got the wrong one while back. There are lots of 86-89 modules around. Should you need one, try ebay, "Corvette ABS" or Corvette ABS module". Let me know. I may know someone who has one, the one I sent back.

Troubleshooting this, hmmmm. OK. You may consider getting a spray bottle filled with water, and individually hit each wire associated with each sensor, the wire connected to the sensor. See if maybe your getting some absorption somewhere. Spray around the wheel bearing also. If you get really wild, use a garden hose on each wheel, individually of course. Road test each time. See if you can light up the ABS light. Then spray around any connections, etc. If its water that's doing it, maybe it'll show up. When you checked the sensors for resistance, did you remove the sensor or check on the car. By removing the sensor, you can clean them and inspect the reluctor inside the wheel bearing.

Also, search archives for ABS. One gentleman has a very good post on checking sensor circuits. With the newer module, much easier, just hook a scanner and watch the 4 different wheel speeds.

Does the ABS light illuminate after you start rolling or when wet, ABS illuminates with key on engine off?

Be patient. If you have the factory service manual, read up on ABS. See if the trouble shooting charts mention any water problems.

Let us know.

dlmeyers 90 coupe zf6 3speed shocks

 

The light usually comes on sometime when I am moving. Sometimes the ABS will kick on a few times while stopping before the light turns on.

Last night I took more readings (while everything was still wet) and found the left rear wheel sensor had continuity to ground. I'll recheck it when everything dries out. I never get common problems. I should rephrase that because I get the common problems too.

I may eventually investigate installing the newer module. I would hate to go through this anytime there is a problem. I'll let you know what I find.

Thanks

 

Good job.

If the rear wheel sensor is going to ground and getting continuity, it can cause problems for the module. In addition to keeping track of the left rear wheel speed, the sensor speed for the LR is used along with the right front wheel to determine vehicle speed. Read that in some book, can't find it in the ABS training book. The sensors are around $55 from GM.

As a comment, the ABS system is really pretty reliable. Heavily engineered for little or no routine maintenance, (so they think), the system has many self checks, good pump from Bosch, supposed to work.

Let us know.

dlmeyers 90 coupe zf6 3 speed shocks


[Modified by dlmeyers, 4:34 PM 10/24/2002]