ThomasC2

Strange that you don't get the 2 seconds glitch. My car is a 1992, built in sept -91. Wonder if I maybe have an older version of my CCU compared to you. If so this means that this maybe works for older cars to (but with the 2 sec glitch).

rollingjack

By PET are numbers for CCU follow:

964 659 047 00 till end of 1990 and
964 659 047 01 from 1991.

CCU in my car is with label 964 659 047 00. Shows like he is older unit.
No wonder by car with age 18 year and with 2 previous owners.

ThomasC2

OK, then mine is newer than yours. All this maybe just depends on luck :-)

Will be really interesting when more people here tries out this soloution so we can see if there's a pattern!

Wachuko

So you get rid of the rear blower (I guess you still have to put a bypass pipe in there), still have use of the heat (less of course since you do not have the rear blower sending all that heat inside), engine looks less cluttered... hummmm....

Photos of what an engine with this mod looks like?

dfinnegan

Here's one . . .

dfinnegan

Here's the one you want . . .

mpeters951

All, I jumpered the relay as indicated above in my '90 C2. Works exactly as it should, w/o delay in fan speed recognizing the speed setting. I used all points on temp dial with all speed settings on the other and is in good working order.

I did this with the resistors still in place. I think I'll pull those for the purpose of tidying up and report back. Thanks so much to those who have posted to this thread with real experience(s) and suggestions. I've been monitoring such with the hopes that someone would come up with a fix. Looks as though we're there, inclusive of early prod date cars. Mine is 3/30/90, with original CCU.

ThomasC2

Good to here! would be great if some more of you guys could try this fix. Regardless of if you have the bypass pipe or the blower installed. It would be good info just to understand if this is the "final setup" or if there any other issues. It's a very easy test to do, just remove the relay and connect the jumper cables as in in the pic.

Strange though that you don't got the hesitation on fan speed 4. So far it's only me...

Wachuko

+1 Would be helpful to have one post with the complete steps (photos also would be great)... and maybe get that in the diy section as well.

Twood

Rolling Jack
Where do I send the check?
I have followed your instructions and have spent just 5 minutes fixing a problem that has been perplexing me for over 12 months . I had given finding the answer and only tagged on to this thread to see others suffer the same frustration.
Subject to a full test (i.e a cold day - they are on there way) everything appears to work absolutely perfectly. My C2 was build November 21, 1990 and subsequently is a '91 model car. Previously, same as all early cars, my A/C would only work on the blue dot.
All hail Rennlisters.

Turbohead

As part of an engine conversion all the wires were cut in the engine on my 90 c-2 Body. I s there a way to pick up these wires in the harness under the seat or some other way fool the CCu?
Any help would be appreciated
Elliot

Ag02M5

Any issues with those wires getting too hot?

rollingjack

I´m happy if somebody find, that this solution is useable

don´t forget to disconnect rear blower plug. Without disconnecting rear blower start run in high speed.

MPB993

Thought we could find a solution for early 964s as it just needs to get 12V to the ccu pin G19 to fool it, assuming similar ccu in 964/993s? For 993s its a single jumper, looks like 2 jumpers for 964s but same approach. For 993 only works if the blower fuse is intack (although replaced for a smaller version) as this is the source of the 12v and codes on ccu are cleared.

rollingjack

You mean? Early 964?

I have tested this 964 659 047 00 unit. Works well.
Or I missed something?