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AR15.COM
9/14/2001 10:29:20 AM EDT
My wife has a 98 Jetta and when she turns on the A/C it quickly over-heats... What should I check first?

[email protected]
9/14/2001 10:31:45 AM EDT
[#1]
Raditator fan.Check and see if its coming on at all.Check the fuse that runs it also.

[heavy]
9/14/2001 10:31:52 AM EDT
[#2]
Check you electric fan.
9/14/2001 11:46:21 AM EDT
[#3]
Quoted:
Check you electric fan.
View Quote


Agreed, newer cars with electric fans usually have dual fans. One that runs when a certain temperature is reached and the other kicks on when needed.

However, these cars that have electric fans run constantly when the A/C is on to keep things cool due to the added stress on the engine.

My guess would be that the temperature sending unit has gone south or there is a blown fuse.

Let us know what you find.
9/14/2001 11:50:12 AM EDT
[#4]
fuse is good, but the fans don't come on [:(]

let me guess, this is gonna be expensive....
9/14/2001 11:54:00 AM EDT
[#5]
Could just be a relay.  Check that next.
9/14/2001 12:16:05 PM EDT
[#6]
If the fuse is good, your next thing would be to check the fan switch, and the fan relays. Before you go crazy, how many fans do you have? I would take a look at the connector that goes into the fan itself and if you have a two wire connector, jump it directly from the battery, one positive, one ground, that will spin the fan motor to verify if it is working. Next you should check the fan switch which could be on the thermostat housing and it looks similar to the water temperature sensor. It can also be located on the radiator, and in some examples on the intake manifold. Basically on a two terminal switch, use an ohmmeter to check resistance between the two terminals on the switch with the connector off the switch. Briefly let the motor reach normal temp, and at this time the resistance between the two terminals should be close to Zero. If that is the case, then your switch is good and the relay is most likely bad. It is not going to be expensive and it is something that you can do yourself at home. The switch is about $65 if needed. Get a manual to help locate the exacy position, I am not at the shop and can't recall off hand the location of the switch.
9/14/2001 4:32:39 PM EDT
[#7]
Quoted:
If the fuse is good, your next thing would be to check the fan switch, and the fan relays.
View Quote


Shawn,

Remember when I came out there?  AZ heat killed my fan switch, and on the way home I got stuck in traffic going uphill, and the result was a new radiator at 5 1/2 extra hours of travel time.

If you unplug the plug from the sensor/switch on the engine and short the plug (on the wiring harness, not on the sensor) with a paper clip, the fan should run.  If it does (and it will), you know that the switch is bad.  Should be under $40 to replace the switch.  Do it SOONEST.

-Troy
9/14/2001 4:43:40 PM EDT
[#8]
Also, because the engine has been overheating you should also ensure you have adeuate fluid in the rad.  Wait until the engine is cool and check the fluid level at the rad cap.  Should be only an inch or two below the cap.
9/14/2001 5:51:06 PM EDT
[#9]
I imagine Kurt has fixed that problem before.