andrew911

Hi- I posted a couple of weeks ago, and was largely having a discussion with adrian regarding my climate control unit in my 1993 C2 that is acting up- (https://rennlist.com/forums/showthre...ferrerid=12720) The CCU is making the outside A/C fan turn on and off while at the same time opening and closing the heat servos in the trunk- they all cycle together every few seconds when the heat is turned on by turning the temp switch to the red dot.

The company I bought my used/rebuilt CCU from said the problem was from a bad relay, and they sent me the relay part number 964 624 010 02 to put in- its a used unit, and was probably checked by them for operation (they didn't charge me for this part). Adiran doesn't feel that any relay would cause this, and I tend to agree with him, but I need to at least try it before going back to the company and asking for a different CCU unit. My problem is, I have no idea where this thing goes! It is a relay attached to a thin metal plate- the plate has two holes in it, and the plate itself is about 9 inches by 10 inches. Does anyone know where this goes or what it even is?

Thanks!

Andrew

mojorizing

Hi Andrew,
According to my PET CD, it's a valid part number and it's a final stage blower regulator. It's location is a question....
Items on the PET CD are arranged closely to how they are physically located on the car, give or take. Given this I would say this part is situated in front and below the CCU in a vertical position.

What is your plan with your old CCU? You interested in selling it to me?

later, mojo

JasonAndreas

Its mounted in the front trunk, on the firewall between the fuel tank evaporation unit/reservoir and the plastic housing for the heat/AC. You need to remove the plastic guard (i believe its held on by two screws) that protects the heat/AC servo units and the final stage blower relay will be at the top, dead center of the firewall.

Herbie

There are no relays in this device.

There are only solid state components, mounted in that location because of their heat dissipation.

andrew911

OK- I think I know where it is located by Jason's description- I'll have to fool around with the part tonight to see if this thing makes any difference.

Mojorizing, I have my original CCU, but the tiny fan kept running in it- that's what started this whole thing. I don't want to give it up yet until I have this sorted out- one of my options could be to get that unit rebuilt if the used unit I have in there now is the wrong one.

I'll update everyone- thanks for the input. By the way, since Mojorizing reminded me of why this whole thing started, why the heck would the tiny fan motor in the CCU need to stay on for 10-20 minutes AFTER the car is turned off?? Mine woudn't turn off and was draining my battery faster than a battery in a sitting 964's should drain (i.e. one day instead of three days ) I must admit- back when the 964 first came out people sited the HVAC system of the 964 as one of the major improvements over the prior 911- I would have paid a premium to have the "regular" HVAC system from my 1987 911 in my used 964- this thing stinks and is taking away from the enjoyment of owning a Porsche! If I wanted electrical gremlins, I would have bought a Lotus or Maserati! Sorry- I had to vent....

andrew911

Here's the update for anyone who may have been reading this thread....I plugged in the replacement part, and......no difference! Of course, I didn't really think this thing would do the trick after Adrian and everyone else gave their comments! Now it's back to calling the shop and telling them this CCU they sent me doesn't work, and if they could send me another used CCU to try, because I have no heat... I could believe the servos were acting funny if they were bad, but I don't believe they would cause that A/C fan to go on (the one under the front fender), so I think its the CCU.

Andrew