RicardoD

My 1991 C2 had the issue where the heat temp control would work properly but then the vent heat would diminish over time, requiring me to crank the temp **** even more. This aligned with either CCU fan not working properly (I would hear it whine sometimes) and / or the thermistor chamber being clogged up. I took plenty of photos to help others and documented my process here.

First a thank you to ToreB and his excellent CCU guide here:
http://www.porschehvac.bergvill.com

Also the Project Shrek CCU repair thread:
https://rennlist.com/forums/964-foru...ent-trial.html

Greg's where do get a Denso fan thread with Paul 902's list of Denso fan options:
https://rennlist.com/forums/964-foru...-rear-fan.html


And these threads:
https://rennlist.com/forums/964-1989...y-ccu-fan.html
https://rennlist.com/forums/964-foru...-opinions.html

RicardoD

CCU = climate control unit

First, buy some Blaupunkt radio removal tools. You can use a U shaped piece of wire but for less than $10 you can get a pair on eBay.

Removing the CCU was the hardest part of the entire project for me. I could not get the left side to budge. I actually had to lie down in the driver's side footwell and by some miracle I could see the left side of the CCU spring side latches. Then with long think steel rod (a Shish-kabob skewer) I was able to unlatch (push in) the problematic top latch from the back. After removing the CCU I can tell you what the right technique is (see my photos below).

You release the CCU with the Blaupunkt tools but you really have to push from the back. I used a long screwdriver to push.

RicardoD

Next you move on to the connectors. There are two back side connectors that latch on one side. You rotate them out.

Once you have the CCU unit removed you can see that the fan pulls in air from the cabin through the grated hole in the front past the thermistor. The fan is hooked up to a rubber tube to guide the air through the CCU.

RicardoD

Next you remove the faceplate from the CCU. Its a bit of trick to push all 6 tabs down and so you can move the faceplate forward. I used some metal chopsticks to push and hold the tabs down.

When you do get the faceplate released don't push out too far because you have to disconnect the ribbon cable.

RicardoD

Next you remove the faceplate PCB. Be careful here not to damage the thermistor.

RicardoD

After the thermistor is clean carefully put the faceplate PCB back into the faceplate.

RicardoD

Now comes the part that you make you feel like a super mechanic Ninja. Thanks to Rennlister previous posts on this topic you do not have to worry about spending $300+ for the Porsche CCU fan replacement part.

A fellow 993 Rennlister figured out you have several options to replace the Denso fan for the 964 & 993 CCU fan assembly.

Denso part numbers: 173000-0xxx

-0410 Porsche 964.659.148.00
-790 Chevrolet
-0691 Audi A8 1994-98
-0860 Honda CR-V (european only?)
-0741 LandRover Discovery <--- has worked for other 964 owners
-0770 Jaguar XJ8 1998-03 <-- I bought this one and it worked!
-0632 Chrysler 300M, Intrepid, Concorde <--- has worked for other 964 owners

I used eBay and found the cheapest one I could, for $13, from a used Jaguar. I did email a few Land Rover dealers to see how much a new one of these would cost but no one was able to help me out. I'd rather put a new one in my car.

These fans consists of three key parts. The fan motor, the plastic fan housing (with center bearing, and finally the black plastic outlet port.

You need to perform a Fan-ectomy. That is you want to transplant the donor fan motor and matching black plastic fan housing over to the Porsche fan outlet port. The Jaguar fan outlet port is a mirror image of the Porsche one so it won't work. The Porsche fan is a 1980s design and the Jaguar one appears to be a later design from the 1990s. Take note of the wiring colors as well to make sure your fan spins in the same direction when you hook it back up to the CCU.

I used a small 9v battery to get the fans to spin. It was obvious how much easier the Jaguar donor fan spun when hooked up to the battery. My Porsche fan spun, but sometimes I would have to help it get started, and I could also hear some bearing noise.

RicardoD

Clean up all the parts as best you can and move the Porsche fan air duct port over to the new donor fan assembly.

You will also need to cut wire and transfer over the CCU connector to your new fan assembly.

Finally you can put the outer bracket on and re-attach the fan to the CCU.

RicardoD

Finally, reattach your updated CCU fan to the CCU unit and plug it back into the CCU.

I had a very difficult time re-attaching the top CCU connector. I actually had to use a quick clamp to get enough pressure for the connector to engage. I have small weak hands!

RicardoD

Finally I have stable heat controls in my car and I can fine tune the temp I want!

Now what idiot defined the CCU button coating material that it wears off in every 964. Even the low 30k mile 964 I saw pictures of recently have this problem!

ChaoticBliss

Excellent write up. Thanks for the info.

pi5tolpete

As usual, a terrific DIY. Thanks!

Vandit

Nice.

I noticed mine was disconnected and reconnected it. What followed was a bunch of loud and annoying squeaking and groaning from that little fan. So I disconnected it again.

I typically run my car at max cold all the time so I guess its operation doesn't matter as much.

YaHoo!

Hats off to Ricardo for another EXCELLENT DIY thread! Thanks Ricardo!

jorijori

Muchos gracia! This will come handy 1 day. Should be in DIY section.

I have a question since you have opened up your CCU, on my car 93 C2, the AC blows towards my feet & I can't change it using the two levers, do I need to replace the whole CCU or just some components inside the CCU? TIA