Steve 96C4S

Hi folks,

Haven't had A/C for 3 months in the hot DC summer. Indie checked lots of stuff but is stumped. Thinks it could be the Blower Final Stage AKA Controller AKA Blower Regulator (not the blower resistor), but he needs to get it from a junkyard since they have a return policy vs. new where he can't return it if that's not what is wrong. Anyone have a suggestion about where to find one or know where one is for sale that is returnable? He'd hook it up and in 10 minutes know whether this is the issue or not.

Part # 964 624 010 02.

The car is low on self diagnostics he said. Everything seems to be working but I'm not getting A/C. It's a $780 part new but he said I should be able to get it cheaper, a lot cheaper from a junk yard. He can't find anything else conclusive that it could be. He said it's too old a car to do a computer generated check.

Sometimes the fan will just stop working for days at a time. Then, it will start working again but if I dare press the A/C button, the fan stops and that's it. No fan, till I restart the car.

Thanks,

Steve

ToreB

Hi Steve. Are the interior blower fans working normally when you turn the fan speed ****? If so, there's nothing wrong with the blower final stage.
When you hit the A/C ****, the fans stop. What fans are stopping, and what A/C **** are you pressing? The small or big snowflake?
Cheers,
Tore

Steve 96C4S

Thanks for the reply. When I get in the car and drive it, sometimes the blower fans won't blow anything, not even fan air. The A/C is off. Then, out of nowhere the fan comes on and blows fan air. When I press either A/C button the fan just stops and won't come back on.

When I restart the car, with the A/C off, the fan may come on again. Totally intermittent. Driving me and my mechanic crazy. I only use the small snowflake by the way but it doesn't matter, as pressing either will stop the working blower fan.

Does that explain anything?

ToreB

Intermittent fan control problems may be due to wear in the fan speed control potentiometer in the CCU. It might be possible to use a good quality electronics cleaner on the pot to get it working again.
However, the dependancy on pressing the A/C button makes me suspect that you have an internal problem in the CCU. Such faults are very seldom compared to external faults. I do not think you have a final stage amp problem, the final stage is unaware of any A/C operation at all.
The above of course assumes that there's no wiring fault or that the CCU has been changed to an incompatible unit.
You might be able to lend a CCU and test it in your car to determine if there's anything wrong with your unit. If so, it's fully possible to fix.

Maybe a fellow Rennlister in your area would help?

Cheers,
Tore

d ward

If it was me I would invest a few $ in the diagnostics kit that toreb does and read the hvac fault codes first, rather than spending hundreds of $ changing parts and hoping I get lucky
Or take it to a shop that has the diagnostic equipment to help diagnose the problem

Steve 96C4S

Thanks for the replies. I'll pass this info on to my indie and go from there....

ToreB

To be honest, I don't think an OBD tool would be able to discover this fault.
Come to think of it, a quick test with a different CCU in your car, or using your CCU in another car could be the quickest path to solving this.
We're here to help if the CCU proves to be both faulty or OK :-)
Cheers,

KBell

Steve

Show me the part.
I may have it sitting in the basement.
I took my AC out years ago.

Kevin

Steve 96C4S

Working on getting a picture of it. I have no idea what it looks like and will have to research it. Thanks!

NP993

I keep getting the sense from your posts, Steve, that your indie isn't a very good mechanic.

Steve 96C4S

They mostly do BMW and Audi. My neighbor brought his 2002 996 TT there and was really happy with them so I went to them to after my last Porsche mechanic couldn't figure out after many times there how to fix the A/C last year after he had it for many weeks off and on.

This current mechanic finally fixed it but this is now a new problem a year or so later.

Hey, if someone knows a great Porsche mechanic that's NOT IN VIRGINIA!!!!! but in the Rockville MD area PLEASE LET ME KNOW.

With the traffic in our area, I am not driving to Virginia during the week. I haven't the time nor patience to sit in bumper to bumper traffic for an hour or more each way. I know there's places in N Virginia to take it to but I'm not interested in doing that anymore.

There's the Rockville Porsche dealer I guess, but they may want to keep replacing expensive parts. I just don't know what else to do at this point. It's been 3 months and it was 92 degrees today with a 102 heat index. I was dying in my car. I'll give this guy another week to do something and then I'll look for other alternatives I guess.

NP993

Matt DeMaria in Gaithersburg, right next door to you. Probably the best air-cooled guy in the DC area. Stuttgart Performance Engineering.

Steve 96C4S

I've heard about him. I'll remember his for next time... or this time if my mechanic still can't fix this soon.

Rental cars are starting to become a drag at $37 a day. I only have to use them here and there when I bring it in there but it really adds up over the course of the year.

sr

NP993

If your mechanic is asking you to foot the bill for his parts-swapping adventures, find another mechanic.

Quadcammer

why wouldn't you just drive your mercedes when its that hot out.

makes no sense.