Spencer May

Hey everyone just wanted to post about something that was seemingly impossible to find on the internet. I have an early 2000's audi tt quattro (180hp version) that seems to be different from EVERY other 8n out there in a few ways. One of those is that I have two coolant temp sensors: one is a 4 pin blue (square, not the oval square in the typical 8n), and the other is a 2 pin white (rectangle) just down the same coolant line closer to the radiator. I could barely find the first sensor, but it took me a week or two to find the second, even with all the posts in the mk1 discussion. I was able to find both of these sensors through parts geek. The first 4 pin is in a few places but the 2 pin I can only find in one place.

4 pin blue - 2000 Audi TT Water Temperature Sender - 919-002 Replacement
https://www.partsgeek.com/ss/?i=1&ss...Sender&x=0&y=0

2 pin white - 2000 Audi TT Quattro HVAC Temperature Control Switch - SKTS369 SKP
https://www.partsgeek.com/catalog/20...html?brand=skp
(props to anyone that can explain what this is???)

Hope this helps someone out!

Geomeo

The second one says it's a HVAC Temperature Control Switch. HVAC is not a "coolant" temperature sensor. It's for the temperature of your HVAC. Heating and cooling of the inside of your car etc.

Spencer May

Yeah I kind of get that, but I'm not sure I understand why the ECU needs a reading on the coolant temperature for the HVAC. Maybe for heat temp from the heater core or info on when the radiator needs kicked on? Also, it is a coolant temp sensor if it's a sensor for reading coolant temp

Geomeo

Meh apples to oranges. If you type in coolant into google it does not come up with Freon. The car is over engineered. I’m pretty sure when it malfunctions or the hvac is about to explode the mil light will come on. Saving you from catastrophic failure. Shame that scheme wasn’t implemented on the timing belt.