helmet155

TIA for looking and reading below.

All testing was with ignition off.

I tested my oil cooler fan and A/C condenser fan for proper operation.

Oil cooler: Low/High speed on Oil cooler both good

A/C Evaporator Fan: Low speed nothing, high speed good

I used the same relay for both (popped off the relay cover and actuated both coils inside relay, then switched from R04 to R14 location). Both relays were checked for any previous owner internal jumper modifications to run high speed only.

I measured the resistance on pins 5 and 7, got 0.8 ohm for the oil cooler side and 700 ohm for the a/c side...so a/c side ballast resistor is seemingly toast, confirming my test using the relay.


My A/C blows quite cold, but if I run it for extended periods with temperature control set to the blue dot my evaporator ices up. I think the evaporator ices up because vent temperatures are quite cold, then after 30 minutes or so and after a few stops whilst running errands, I get ambient temp out of the vents and after parking the car in the garage or parking lot I get an unusually high flow of water (evaporator thawing IMO) from the drain hose under car.

If I run the temperature control **** at the 18C (9am) position it works well and the evaporator doesn't freeze up from my testing.

Here's the kicker: I have felt the a/c evaporator fan running and I can hear it, but must be running on high. During driving the fan can be heard clicking on and off every so often also.

Question 1: Will high speed operation of the condenser fan cause the evaporator to ice up?

Question 2: I looked at relocating the evaporator temperature sensor, but it doesn't really look like it can be relocated, due to the 'cover' that the sensor is fed through predicates it's location, would someone please explain how to relocate it?

Question 3: If low speed is INOP on the a/c condenser fan, is High speed substituted? Seems my high speed fan runs when a/c is on.

Last question, but related to the oil cooler fan: If I wire a manual switch behind the CCU, does anyone have a picture of what the connector and pin look like? If I wire a manual fan, no way am I going to cut the CCU harness but instead I would prefer to release the female pin of G12 (green/black wire) from the ccu harness connector and wire in the switch, therefore not making any permanent modifications to the under dash harness. Maybe I will start a new thread for this one.

Thanks,

Brett H, in South Orange County...

C4 NLW

My Porsche dealer diagnosed that my AC system was iceing up. He replaced some bits to correct this although it still operates much as yours. When I drive with the air con set to the blue dot the vent temp is 40 degrees farenheit in ambient temps of 36 to 38 degrees centigrade. After some time, around 30 minutes the vent temp rises to between 50 and 58 degrees Farenheit. If I turn off the AC for a few minutes and restart it the vent temp drops to 40 degrees farenheit and the process of temp lift to 50 to 58 repeats after about half an hour. Loking at the operating specs of the system in ambient temps this high 55 degrees farenheit is not far off the mark. There is a table around somewhere in Celcius and Farenheit. Perhaps on this site or on P-Car.com

The bits the dealer replaced are :-

Expansion Valve, Desicater, Distribution Piece, O-rings.

A/C in my Jeep and my mini is like a refridgerater compared to the P Car.