1CAMWNDR

iTrader: (21)

My low-coolant light is coming on randomly. Sometimes it comes on, and sometimes if I turn off the ignition and open the door, if I restart the car, it isn't on. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
I checked the radiator and it is full. Might I have a bad sensor? Where is the low-coolant sensor?
Any help is appreciated.

AndUAndI

That sensor is right below the radiator fill cap and the A4 tranny cooler line. The circuit on a 1998 has nothing to do with the PCM, so if the radiator is full it is either a bad sensor or connection. Pull the connector and see if light comes on (can't remember)...if it does come on when pulled then you know the ciruit is opening up somewhere.

1CAMWNDR

iTrader: (21)

My car is a 1999 so what problem might there be in the PCM? I will try and disconnect the sensor if I can get the car to start without it lighting <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> .
Thanks for the tip.

30thta436

iTrader: (10)

I have replaced a bunch of the sensors. Never any thing else. If you unplug it the light should go off not on.

1CAMWNDR

iTrader: (21)

OK Here is the latest:
Started the car and the light was on. Unplugged the sensor and the light stayed on.
Later that day, the light was off. With the car running, I unplugged the sensor and the light stayed off <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . At this time a friend drove up and we talked for a few minutes while the car idled. When I got in, the light had come back on <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> .
Drove 20 mins, and the light stayed on. Went shopping for a little while. Got in car to drive home, and light was off! Stayed off for the 20 min drive home. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Guess I need to invest in a multi-meter and learn how to use it. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

<small>[ March 06, 2003, 09:18 AM: Message edited by: 1CAMWNDR ]</small>

Cal

iTrader: (1)

1CAMWNDR,
It sounds like that signal was basicaly "floating" or just picking up random voltages out of the air once you unplugged it. Try installing some kind of jumper in the end of the connector to provide a stable "simulated" signal to the PCM. The light should either stay on or stay off. If it still randomly changes, the problem is elsewhere. If it stays on, take out the jumper and start experimenting with different values of resistors. If it stays off, leave the jumper in permanently. BTW, multimeters are cheap and easy to use. It you need any help with that, ask away, I have 30 years experiance using them.

<small>[ March 06, 2003, 10:23 AM: Message edited by: Cal ]</small>

1CAMWNDR

iTrader: (21)

Thanks Cal; I may need to tap your knowledge resources here in a few days or so.

pjb

iTrader: (2)

when the light comes on it won't go off unless you restart the car. I replaced the sensor and problem went away. I thoroughly cleaned the inside of the old sensor and reused it several monthes later when the problem came back. Now I just swap and clean the sensor for next time. Happens about twice a year.