This stupid light keeps going off?!?

Jadewombat · Post by **Jadewombat** » Sat Jul 19, 2003 12:12 pm

I don't get it, I have this '86 I'm taking care and the low coolant light goes off, but not all the time. I can get in the car, drive either around the corner or for an hour straight, then shut it off, get back in and the light comes on like clockwork. I've bleed the system like five times and there is PLENTY of water in BOTH tanks. What is causing the system to pressurize?? It doesn't run hot either, as in the needle is one width above the halfway mark.

Post by **Piledriver** » Tue Jul 22, 2003 6:05 pm

It goes off when I turn on my lights sometimes... Probably a little astable flasher getting triggered by line noise.

In other words, it's probably in the dash.

I haven't looked at the circuitry, but you could probably put a $5 radio shack buzzer on the coolant sensor temporarily to "see" if the sender is actually doing anything:
A longer term fix would likely be a filter cap added to the circuit somewhere.

Electrolytic caps go bad at about 10 years...

You DO know it's supposed to come on (flashing) for about 5 seconds when you hit the key---It's a self test sort of thing.

I have an 88.

Jadewombat · Post by **Jadewombat** » Wed Jul 23, 2003 9:46 am

Piledriver wrote:It goes off when I turn on my lights sometimes... Probably a little astable flasher getting triggered by line noise.

In other words, it's probably in the dash.

I haven't looked at the circuitry, but you could probably put a $5 radio shack buzzer on the coolant sensor temporarily to "see" if the sender is actually doing anything:
A longer term fix would likely be a filter cap added to the circuit somewhere.

Electrolytic caps go bad at about 10 years...

You DO know it's supposed to come on (flashing) for about 5 seconds when you hit the key---It's a self test sort of thing.

I have an 88.

It does go off after five seconds like in my Golf, and I know the only two scenarios where it comes back on are when it overheats or is low on coolant. Neither which are the case though. Like I said, I can get in it and drive anywhere, whether it be around the corner or across town, stop it, get out for a few minutes and restart it and the light comes on...just like it's pressurizing somewhere. And it only does it when I restart it the second time. I may just replace the cap just to eliminate that as a factor. Thanks.

Post by **Piledriver** » Thu Jul 24, 2003 6:10 pm

Silly question--- What % coolant/water are you running ?

Jadewombat · Post by **Jadewombat** » Fri Jul 25, 2003 9:18 am

Piledriver wrote:Silly question--- What % coolant/water are you running ?

50-50 blue VW glycol and water.