I''''ve taken my Saturn SL1 to get it inspected 3 times and every time they get around 20 not ready codes like the battery has been disconnected and it wasn''''t driven enough for it to complete the test cycle. There was at the very least a week inbetween inspections with my driving it everyday 38 miles round trip to work and back. I have noticed that early in the morning the light in my instrument cluster flickers slightly. What could be the cause of this? I have been told it could be caused by a faulty temperature sending unit, and my temp gauge does stay way on the cool side. Could this really be the culprit??
Edited by: mercenarydragon

 

Check for bad battery connections.

And which light flickers. Theres a lot of them.

 

The whole cluster flickers. It''s barely noticeable. If I rev the engine they stop momentarily then resume flickering once the engine falls back to 1000 RPM

 

Huh - Have not seen that in a long time.


From what you describe, I would guess that at least one set of the diodes in your alternator has failed, and the alternator needs to be replaced.


Usually, you can go down to AutoZone, and they will run a test on the alternator to be sure (often at no charge to you). That would be my first step ...

 

Yep, sounds like an alternator problem.

 

That''s what I thought it was... Seemed like a voltage regulation problem. Thanks guys!

 

Definitely check the temperature sensor and the thermostat, not that these have anything to do with the flickering lights. If the gauge reads low all the time, one or both of the items mentioned above may be faulty. Take a meat thermometer and place it in the overflow tank with the engine running at medium to high idle (fully warmed up after about 15 minutes or so). The water should read above 180 degrees with the dash gauge reading between 1/4 and 1/2. If the temp is fine but the gauge is off, then the sensor needs replacing. If the water is below 180 degrees and the gauge reads at 1/4 or lower, then the thermostat needs replacing. They may both need replacing. If the temperature takes a really long time to come up, then the sensor definitely needs replacing. The temperature should start registering after only about 5 minutes of driving in weather above 30 degrees. It is also important to have proper temperature and proper temperature reading because if the gauge never goes above 1/4, the engine will stay in open loop, and will idle too high. Fuel mileage will be reduced, especially in the city.