brandon19761

Hello all. Well I just got done re-doing my timing belt and front seals. I fired up the car and the good news is it is smooth as ever now.
Only thing is my ABS light has come on. I checked the fuses and made sure the relay was tight. The only thing is I still need to put the ps pump back and the AC/Alternator belts. Would low voltage from not having the Alternator going trip the ABS light because the computer is seeing low voltage? The battery connections were good, but the batt was probably only 70% charged.... I hope that's all it is. I will find out when I finish it........

Thanks

Martin

Yes! The ABS light is on in a bulb test mode when your alternator warning light is on.

brandon19761

It went away when I hooked the alternator back up.
What is bulb test mode? My car is missing the test relay?

Martin

No test relay required, there is simply a diode in the instrument cluster that feeds the abs light when the alternator light is on. I once spent many hours trying to find a fault in a mercedes Benz brake circuit to find the same thing, only on that particular car the alternator warning light bulb had failed so took a while to work out it was the alt and not the brakes.
Martin

brandon19761

I see. Because my '88 is missing a test relay that my '89 has.... I think it is G3 if I remember correctly...

Van

The "test" part of that relay is just to test if fuses are good. you've never tried it out? One of the coolest 944 features. You put a fuse in there, and if the green light comes one, then the fuse is good.

I'll sell you one, if you want...

Oddjob

ABS system is very sensitive to low voltage and it will be the first system that faults out when the battery is low or the alternator is failing.