View Full Version : Brake Master Cylinder humming after engine off

Banana Bender
12-16-2005, 11:39 AM
89 SC. I read a few of the posts on ABS problems on these, but I didn't see this specific symptom mentioned. Thanks ahead of time. You guys are always helpful.

12-16-2005, 05:50 PM
Sounds like the ABS pump motor relay is bad. The humming you hear after the ignition is turned off is most likely the pump motor still running. The ABS pump relay is located on the passenger side of the engine compartment attached to the firewall over by the AC accumulator and is brown in color. It can be a little difficult to access sometimes. The relay should be available from the auto parts store. You should be able to find a part number if you search this site.

Originally Posted by rhodes588
Okay for some reason the ABS motor was drawing power all the time and drained my battery. Everytime i shut the car off, you can hear the ABS motor go on and it sounds like its vibrating rapidly. I pulled the fuse underneath the hood in the mean time. I need help ASAP!! Someone help!

Go to Autozone or Advance Auto, get a GP Sorenson Relay MR120. Should cost about $14 or so.

This is the ABS Pump Motor Relay. The only way an ABS pump can run with the car turned off is if this relay's contacts are stuck closed. Good thing you pulled the fuse because it would have burned up the pump motor in short order running that long.

Mine did the EXACT same thing 2 years ago. The relay is located on the passenger side firewall under the hood. I can't tell you which one it is right off but maybe someone else on this fine board can tell you exactly which one of the two or three relays in that location it is. You could also do a search for "ABS Relay" on this board.

Good luck


12-16-2005, 09:22 PM
Tap on the relay box. Its the brown top relay on the passenger side firewall behind and below the wire bundles. Its on the engine side of the hood support.