I have a 1990 750iL. I can hear what sounds like a valve of some sort open and close in the brake system at intermittent times when applying the brakes, or even when the car is just idling. The noise is clearly audible as well. Sounds like it is under the dash or near the pedal. I have been told that it is likely the "ABS Control Module." Is there any way to remove and test and/or reset the original unit? No use putting a new one in if the old one can be fixed. BTW, the brakes feel fine otherwise and seem to work okay. Thanks for any help.