Climate Control Head Problem, 86 951, parts help?

[Vroom]

Climate Control Head Problem, 86 951, parts help?

I have a 1986 944 Turbo with about 151K miles. It’s at my mechanic’s shop now. The mechanic had converted the AC system to the new freon setup around December 2005.

Recently, I started to notice that when the AC is running, suddenly, blasts of hot air will come out of the vents--driving me crazy--on an intermittent basis. He continues to experience this problem as he drives the car back and forth to his home.

He says the problem is in the “climate control head or unit” and because he knows I don’t want to spend a large amount of money, suggested that I just live with this. (He mentioned that the part might cost $1000 or more)

My brother in law, who owns Hyannis Foreign Auto in Hyannis, Massachusetts, suggested I consider finding the part at some remanufacturers such as : BBA Reman, ProgRamaInc.com, and *************** (Performance parts). These companies do this kind of work, rebuilding control units. Cost at ProgRamaInc. is usually around $189 to $249 with 3 yr warranty parts and labor , 48 hour turnaround.

However, none of the three above DO this part for an ‘86 951.

Then, my mechanic told me he could get the part "new" for $550.
Part #944 653 0104 01C.

My brother in law suggested I call a local Porsche dealer that he works with on Cape Cod. Clair Porsche said they could get the part for me at brother in law’s cost of $517.92 + UPS shipping. 2 yr parts warranty. They had a different part number: # 944 653 021 04 01C

I rechecked this new part number with the remanufacturers, and they still could not offer to rebuild this part, though one company had it in their system as “being researched”.

1. Have any of you had the same problem with heat coming out of the vents with the AC on? What was your experience?

2. Is the climate control head or unit the cause of this problem?

3. Can you suggest any other places where I can turn to get this “head” remanufactured?

4. Should I just buy it new?

5. Any other thoughts?

Thanks all!
Vroom (White Plains, New York)

[soxnail]

Loss of vacuum can cause the car to cycle to the default heat mode (Porsche did not want people to freeze in event of system failure). I would check this out first.
Sox

[Vroom]

Sox , thanks for the tip.

[bscpanther]

If it comes down to you replacing the head unit, I would buy a used one and save some cash. They are often on ebay and often guanteed to work, a few listed right now.

[Wayne 962]

Sloppy mechanic. The factory manuals have a procedure for troubleshooting this. If any of the three sensors in the system fail and become open (like disconnected), then the system will default to full heat on. This may also happen if one of the flappers in the defroster or the footwell becomes stuck. The proper procedure is to test the proper operation of all of the components in the system prior to making the diagnosis that the head unit is faulty. Anything else is just a bit lazy and "guessing" at a solution. Really good mechanics will troubleshoot and isolate the problem. Not-so-good ones will just start replacing parts.

-Wayne