ABS Question

Ghugly

Registered User
My 90 SC brake system is driving me nuts. Both brake lights are lit and stay lit as long as the ignition is on. I removed the pump relay and jumped the contacts. The pump comes on and pressurizes the system. I checked the voltage on the contacts for the relay coil and it reads about 11 volts and goes to zero when the pump pressurizes the system, so it seems that the pressure switch is making and breaking. However, the isn't enough current to activate the relay. I bought 2 service manuals only to find out that the ABS system apparently operates by magic as I can't find any indication in either manual that there is any wiring associated with it :confused:. The car has less than 100k on it and runs great but stopping this great hulking mass is sort of a problem.

Oh, I did replace the pump relay. It was cheap and available..........and did nothing.

Any thoughts?
 
abs

try priorreman.com for the accumulator ball. after install make sure to check and tighten hoses and especially 2 allen bolts on pump that is fed from main reservoir. a leak there drips directly on catalitic converter and smokes like crazy
 
Ok, so wait a second before you buy an accumulator. (You might still need one, but that might not be all you need.) You said that there isn't enough current to activate the relay. Do you mean that the pump never turns on? You should be able to hear it and possibly feel it in the brake pedal, especially when you first turn the ignition on in the morning.
 
Ok, so wait a second before you buy an accumulator. (You might still need one, but that might not be all you need.) You said that there isn't enough current to activate the relay. Do you mean that the pump never turns on? You should be able to hear it and possibly feel it in the brake pedal, especially when you first turn the ignition on in the morning.

Correct. The pump will only run when I jumper the contacts in the pump-relay socket. There is voltage to the contacts in the plug that should energize the pump-relay magnet, but not enough current/amperage to energize the magnet. Somewhere, I'm guessing, I have resistance in the circuitry. Perhaps the pressure switch? The problem is, that without some sort of schematic, I'm kind of flailing about in the dark. I agree that I may well need an accumulator, but I don't see what it has to do with the lack of current to the pump-relay magnet.
 
Yeah, I think you must have some kind of wiring problem, OR the pressure switch is bad.

Here - this website doesn't have a full diagram, but it has some troubleshooting info on the ABS system. (Good site in other ways, too.)

http://www.35thatr.org/Tips/ABS.htm

I am not sure how much wiring info is in the factory EVTM and service manual, but I will look at mine and see what I can find.
 
good advice-google "teves mark 2" for complete info on these systems

Great advice! Found what I needed in a couple of pdf files for a SAAB. The pressure switch is the culprit. If it doesn't cost me an arm and both legs, I'm getting the accumulator as well.
 
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