I posted this problem in a Buick forum last fall, but never got a satisfactory answer ... so I'm gonna try here! I'm getting the car ready to sell, but I hate to try and convince a prospective buyer to just ignore the warning light!
I have a 1994 PA Ultra with 135K miles on it ... and for the last 5+ years, my "Low Coolant" light on the dash has come on about 15 secs after starting the car, and stays on steady until I turn the ignition off. Coolant level is fine. Low coolant sensor in the radiator was replaced, with no improvement.
According to the troubleshooing chart in the service manual:
"If CHECK OIL LEVEL indicator is lit continuously when oil level is OK, or COOLANT LOW indicator is lit continuously when coolant level is OK, check indicator lead for a short to ground. If wire OK, replace oil level module."
Then the chart goes on in great detail about checking various connectors for various ohms or voltages, ETC, ETC, ETC !!!!
According to the wiring diagram in the manual, there are 3 wires attached to the "Low Coolant" sensor ... Brown (to a signal input on "Oil Level Module"), Light Green (also to a signal input on "Oil Level Module"), and Red/White (to power on "Oil Level Module").
Two questions:
How do I "check indicator lead for a short to ground"? Just a continuity check for all three leads to ground? Continuity on any of the leads = "short to ground"?
Does anybody know where the "Oil Level Module" is located?
Has anyone else experienced this same problem? Any directions or advice would be appreciated!