So I haven't posted anything as of late but here is an interesting one I simply do not have an answer for, nor can I find an answer for. So my car is a 98 A4 1.8T AEB manual quattro. When I turn on my AC (Air Conditioning) it works fine. I usually leave it at around 67-70 Farenheit. However when I turn it all the way to low I feel it get way colder and blow real hard then all of a sudden like I tripped a breaker the snowflake symbol and AC turn off. It stays off for about three minutes at a time like that then pops back to life. Again will run all day at 67 Farenheit. I have the correct amount of refrigerant in there. Problem two. When I sit at idle with air conditioning on after about 10-15 minutes, the coolant temp will slowly creep up from it's normal spot in the middle resting spot in my gauge. When this happened I popped my hood to see if my auxilary fan was on. It was not, nor have I ever seen it on or spin. There is only one more thing I can add to the mix and it is this. My radiator is the split half and half design for the 1.8T automatic. Simply put one side fills with tranny fluid to cool it and the other with coolant. I know it is wrong but i had it lying around and needed a different radiator in there and has seemed to work very well. So my thought is that I could potentially have an AC Pressure Switch that is bad, and a bad coolant auxilary switch or just need a brand new proper radiator. If anyone has any input I am more than open to any thoughts or suggestions. I am more or less concerned as to why my auxilary fan never turns on and why the AC seems to flip a breaker in a sense. I was considering putting in a lower degree auxilary fan switch from ECS Tuning.
Audi B5 A4 Quattro 1.8T > Engine > Cooling > Temperature Sensor > ES#1695 Auxiliary Fan Switch (74-93°C) - 3 Pin - 251959481K
Not quite sure about the operating temp specs of it though...74-93 Celsius for the aftermarket one, where the stock switch operates from 91-102 Celsius. What issues might I encounter running the lower temp switch?
Thanks for reading and again I am welcome to all input. Just like to hear some views before I start doing my own crafty, money and time wasting detective work :]

 

Lol wow, almost four days and no responses. Guess that's what I was expecting from this place as of late. You only seem to get a response if you want people to tell you how pretty your car looks. Well whatever. I believe my problem to be a faulty G89 sensor located under the fresh air intake filter under the hood, above the fan blower. I read my car's codes with the handheld vag com unit from ECS Tuning.
Audi B5 A4 Quattro 1.8T > Search > Vag > ES#9950 V-Checker Scanner - Pro - VAGCHECKERPRO
Thought the little unit was a waste but have ended up using it countless times now to check and clear fault codes. I give it one thumb up and another half thumb because the user interface is backwards and kinda sucks. Only buy the pro unit, the basic is absolutely pointless. The code was a 00787. Using ross-tech's wiki for codes you can scroll through their pile of organised numbers and find this one is for that sensor. So if anyone knows where I can purchase one, that would be helpful. ECS and rock auto both do not have it. I think this is a fairly easy question that hopefully someone gives me an answer too. G89 Fresh Air Intake Temperature Sensor.