abs power relay failure
- Thread starter tbirdtony
- Start date
David Neibert
SCCoA Admin
When mine failed several years ago, it was a bad ABS relay. The relay supplies battery power to the ABS pump that charges the accumulator. If your pump is operating it's not the relay.
Well from that information, the hydraulic pump/motor relay is working, and the pump is building pressure. The antilock power relay will send 12V to the Orange/Yellow wires if the abs module is happy.
according to the evtm manual there is a anti- lock pump motor relay and a anti-lock power relay. i hear the pump motor run at times when the car sits for a period of time. so i think its the abs power relay thats the culprit.
mine is a 93 and abs plug is on drivers side engine bay behind battery and power distribution block. i know some cars have plug in the trunk
I was actually referring to the relay's on the right rear cowl, behind the strut tower(above a/c dryer)
89-90 they are Left to Right a/c clutch WOT cut out relay, pump motor relay & anti lock relay
91-92 pump motor relay ,antilock relay & a/c clutch WOT cut out relay
93 has vacuum brake booster, so longer use's pump relay-I dont have diagrams for 93-maybe somebody here does?
If you hear the ABS pump motor behind the front bumper(left side) running that is usually a indicator that one of the outlet valve's in modulator unit is stuck open or leaking. I think you would get a 23,24 or 25 code depending which one it is. That would also lead me to believe the ABS ECU is powered up if its commanding the ABS pump motor to cycle
89-90 they are Left to Right a/c clutch WOT cut out relay, pump motor relay & anti lock relay
91-92 pump motor relay ,antilock relay & a/c clutch WOT cut out relay
93 has vacuum brake booster, so longer use's pump relay-I dont have diagrams for 93-maybe somebody here does?
If you hear the ABS pump motor behind the front bumper(left side) running that is usually a indicator that one of the outlet valve's in modulator unit is stuck open or leaking. I think you would get a 23,24 or 25 code depending which one it is. That would also lead me to believe the ABS ECU is powered up if its commanding the ABS pump motor to cycle
i have been behind the driver side wheel well and was able to look at the abs unit and there were no leaks and i even got a used abs control module from e bay and installed it with no improvement abs light is still on and no codes. i have a old snapon brick mt 2500 that i use to diagnose problems. i took the abs power relay out and looked at it and it isn't burnt or discolored but not sure how to test it. i can get a nos unit on e bay for about 120.00
I meant a internal leak, bypassing inside the unit.There has to be at least a pass code or something. Why did you replace the module if nothing pointed to that? Take SC-AL's advise.
I've had a 1990 Tbird SC for more than 33 years and for the past couple years my yellow ABS light comes on and stays lit every time I start the car except for the initial start-up in the mornings. I've found out over the last 21 years that the yellow ABS light is not a problem unless the red brake light comes on and stays on with it. Then I just have a very hard pedal and no brakes, but a new relay usually fixes the problem. That has happened 7 times over the last 21 years.
Your pump must be running a lot, and/or drawing higher than normal amps. Also, are the relay's that you are buying not Ford, or Motorcraft?
I don't know why my ABS is prone to failure every 3-4 years, so I've just accepted it as a necessary evil in an old car. When it fails, I slowly and carefully drive it to the nearest Ford dealer and according to my records, they replace the relay with part #E7LY8Z658A. On two occasions they also had to do a brake master cylinder rebuild with accumulator service.