The ABS pump motor relay is not serviceable. It is part of the ABS modulator valve.
The ABS pump relay is intergrated into the EHCU (elecro-hydraulic control Unit) and it is not serviceable. If the ABS pump relay is defective, the entire control unit must be replaced.
Under the bonnet
take off wheels
On a 1995 300zx N/A Coupe it is located behind the passenger seat under the plastic cover where the ABS assembly is. It is in a black box on top of the ABS unit under the black cover. There are two relays one has a raised tang on it that is the abs motor relay the other is the solenoid relay. Should be the same for 1990 to 1995 and maybe more and TT should be the same, do not know where the 2+2 relay is.
Likely cause is an electrical problem in the EBCM. Unfortunately it is replaced w/ the abs pump as they are one unit. Very pricey!
Had same problem, you have to replace the ABS Module. You can take it to the mechanic for about $1,200+ or this web site http://cgi.ebay.com/ebaymotors/GM-CHEVY-PU-SUV-ABS-EBCM-COMPUTER-ECU-MODULE-REBUILD-/390263833938?pt=Motors_Car_Truck_Parts_Accessories&hash=item5add898552
how do you find thepower relay valve circuit for the abs brakes
the relay is in the abs pump
B1245 is Wiper Rear Motor Run Relay Circuit to Battery
The "main relay" is inside the abs computer. If you have the Main Relay code, the abs computer has failed.
If it only makes the sound when almost to a stop there is a ABS wheel speed sensor dropping off and activating, If it buzzs all the time the power and ground wires corrode at ABS pump motor making it constantly run, you can pull the ABS fuse in the underhood fuse block and if the noise stops you will have to replace the pump motor. Hope this helps! I took my 2000 Chevy Tahoe to the repair shop because of the abs light that come on last week and it haded that buzzing sound under the chassis on the driver side all the time even with the ignition off, and the mechanic found a bad ELECTRONIC BRAKE CONTROL MODULE (EBCM) that kept the pump motor running, also he suggested to replace the brake pressure modulation valve (BPMV) when i called the dealership to order that part they mentioned, that they have a "few" in stock because a lot of people are having to replace that part, so if there is a lot of people replacing the EBCM to stop that buzzing sound at the punp motor it maybe the EBCM that is kepping the pump to stay on, working at all time. And searching thru the internet about some info on this matter I found this comment at a website; I have a '2002 model Avalanche Z66 and the ABS light recently came on. A motor or module kept running even after the ignition was turned off. The only way to stop the running motor was to disconnect the battery or remove the fuse. I have found out that the problem is a defective EBCM electronic brake control module. According to three dealers these are being replaced regularly but if your vehicle is out of warranty your on your own. GMC and Chevy know the part is defective but for some reason $$ don't want to do the right thing and recall them. Thomas. complaints.com