Author Topic: 85 NA Jetta, flashing temp ligt and alternator/battery light (Read 3148 times)

jackbombay · « **on:** February 24, 2008, 10:29:33 am »

The owner was driving the car here and the battery light came on about 150 miles from here, and stayed on the whole time, he has driven it a bit the last couple days and the battery light has been on intermittently, sounds like the alternator is quitting to me. Is there anything else besides checking alternator output that I should do?

Temp light, flashing when going up hills, but the needle has not gone any higher than it normally does, is this possibly a bad sensor? The WP is not leaking and the coolant is full. Outside temp has been in the lower 30 the last week or so, fwiw.

jtanguay · « **Reply #1 on:** February 24, 2008, 10:39:28 am »

my coolant light has been flashing for quite a while now.. i just ignore it and check the coolant level in the bottle. its just the level sensor. (i hope :lol:)

i think if the GP light flashes its the water in the rear water separator.

the batt light would come on if the alternator wasn't charging.

jackbombay · « **Reply #2 on:** February 24, 2008, 10:45:56 am »

Quote from: "jtanguay"

my coolant light has been flashing for quite a while now.. i just ignore it and check the coolant level in the bottle. its just the level sensor. (i hope :lol:)

His car still has the owners manual and according to it when the light flashes the car is overheating, but when the needle is sitting where it always has thats not all that believable.

jtanguay · « **Reply #3 on:** February 24, 2008, 11:19:09 am »

ohhh you mean the light that is above the coolant gauge??? mine doesn't have one... although a coolant buzzer would be much harder to miss :lol:

maybe get one of those infrared thermometers and confirm that the gauge is reading correctly? then at least you know its just a sensor.

jackbombay · « **Reply #4 on:** February 24, 2008, 02:37:46 pm »

So which light do you have thats flashing? I really need to buy an infrared thermometer, $30 from harbor freight...

The battery reads 12.6v at rest and with the car running it has 14.0v so the alternator seems to be workingm the light could be on because of a bad diode according to my manual that goes up to 84' but does not cover 85. Says you need a special tool to check it, can I just check for resistance or something else to check it with out the special tool?

smoken u · « **Reply #5 on:** February 24, 2008, 02:54:18 pm »

I had a car come into work with the same problem. blinking colant light, but only intermittently. It could be the sensor which is the most likely culprit. but in the case of the car I worked on it was the actual cluster that was bad.

Buckracer · « **Reply #6 on:** February 26, 2008, 12:02:59 am »

I thought that the flashing coolant light was low coolant. Top her off and see what happens. Also the alternator light, Check the belt tension. I had a belt I thought was ok, I replaced everything else. cables, battery alternator starter, wire ends. just due for a new belt. the new belt hasnt given me problems with the alt. light since, except for retensioning for stretch.

squirrl22 · « **Reply #7 on:** March 28, 2008, 12:11:37 pm »

I had an intermittent flashing coolant light/ temp gauge pegging to overheat. I finally traced it down to some corrosion on the relay. I cleaned off the relay blades, used some dielectric grease, No more problems.