OK GN Experts I need some help!

[joeo86gn]

My brake light on the dash is lit up and won't go out and the brake pedal is hard.The booster motor doesn't seem to be running,I thought it might have been bad so I replaced it with a rebuilt one and still no luck.I ohmed out the pressure switch and it is showing resistance on my meter.Any suggestions??

 

[87NAT]

Buy a vacuum brake setup from G-body parts and put the powermaster on the shelf.

I have had 3 turbo regals over the years and I have switched to vacuum on all of them and never looked back. My car stops great and I can still hold 8 psi on the line and cut 1.60 sixty foot times.

 

[joeo86gn]

powermaster 2

I have considered this option as a last resort,I'd perfer to keep the car completely orginal.I'm going to assume the brake booster/master cylinder/brake pedal from a monte carlo or olds cutlass will work.

 

[zeus87gn]

If your motor isn't running, you can't run diagnostics. so...

Have you checked your fuse yet? If it's blown, you need to replace it and run diagnostics immediately. You have to findout WHY it blew.

Diagnostics are here: Brake System

If you fuse is good, then you need to start tracing the system. There is a logic diagram on the above page, you can make sure the switch is as it should be. If your light is on, and the switch is closed (should be a simple make/break contact - no resistance or very small) power should be going to it. The diagram will tell you the pin on the plug to test for voltage.

If your getting power to the motor, the problem may be in the motor itself.
Try the above and we can go from there.

 

[joeo86gn]

Pb

I checked the 30 amp fuse and it's good,the pressure switch checked out good when I ohmed it out as well as the motor.There are four wires going to the powermaster motor, the pump connector "B" (brown wire) says on the diagram says it's supposed to have 12 volts to ground and it does not.I followed the wire in the harness and it appears to run to the fan relay mounted on the inner fender.I haven't looked into it any further than that,can anyone confirm that the pump connector "B" is supposed to have 12 volts to ground?

 

[zeus87gn]

Pin B is the hot side of the coil in the relay. So yes, it should have 12V when the ignition key is on. It is switched. It may/may not run to a relay, I have never tracked it down (never had that problem). I have heard from another friend it comes from the AC compressor power wire. Someone may have moved it?

Pin D is the grounded side...grouonded through the switch. When the switch closes, the motor is supposed to run. The relay is built into the motor.

Pin C is the hot wire to the motor itself. I believe it is hot at all times. It runs from the 30A fuse.

Pin A is ground for the motor.

 

[disco stu]

I'm having the same problem. The 87 manual says this is hot from the 5 amp RLYS fuse. However, this car does not have a fuse for this. It is an 86.

Need some help and need it quick. If anyone knows or has an 86 manual to tell me where this brown wore gets power from I'd really appreciate it.

 

[disco stu]

Got it. Gets its power from the AC fuse.