diehlryan

All the other fans seem to be 100% operational.

Had a hell of a time getting home from work today with the operating temp running between 100 and 105 the entire way.

Whats the first major malfunction that causes the fan to quit working? Fan itself or some king of switch?

TTinCT

could be your primary fan switch...double check the fuse block on top of the battery to insure that no corrosion as set in....some have reported this as an issue in the past...

TTschwing

It's gonna be a long, hot summer here on AW....

diehlryan

I should have clarified that I've been through the fans not working before (last yr). That was also causing the AC to blow hot air. Fuses were bad, replaced. No problems until now.

Had the AC running today to "force" the fans to run. The fan not running was the larger drivers side fan.

I think I'm going to first look for loose connections and then from there I'm going to replace the switch. What I'd like to do is replace it with one that kicks on before 104deg.

I checked ECS for the switch and could only find them listed under a MK4 Jetta 1.8t. Same switch for TT?

BlueChip

because those temps are a problem. By 112-114 you're not starting to overheat you're fried. The pressure cap has exploded and you have lost your coolant.

According to Audi, the thermostat should begin to open @ 80C and should be fully open @ 105C. If the system is operating correctly you should never see 105C. The fans should bring the temp back down to near the 80C value and you should merrily operate around 90C.
I would worry about any Temperature that gets to 100C or above.

I love my TT and wouldn't want to fry it.

BC

BC

BlueChip

According to Audi the coolant fan control is:
- switched to speed 1 @ 95C
- Switched to speed 2 @ 102C

" Switching conditions - Coolant Fan Control (FC) Thermoswitch -F18/-F54
-F54 between terminals 1 and 2: Closes at approx. 95 ° C (-V7- switched to speed 1).
-F18 between terminals 3 and 2: Closes at approx. 102 ° C (-V7- switched to speed 2). "

I didn't even know that the fan has a two speed capability. Inquiring minds want to know.

BC

specialblend

methinks its the fan switch so im going to go ahead and replace that since its relatively cheap.

i was monitoring my coolant temp levels from the HVAC and it went up to 112 while at idle and the fans never kicked on.

TTinCT

what do you base all of your data on?

TTinCT

with most cars getting closer to the 100k mark...things like heater cores, radiator clogs and fresh coolant will rear their heads....not much you can do other than replace and maintain....

We do not need exploding radiator caps all over the forum....

TTinCT

while 125 is really high....you get the idea...<ul><li><a href="https://forums.audiworld.com/tt/msgs/1512735.phtml">https://forums.audiworld.com/tt/msgs/1512735.phtml</a</li></ul>