ThomasC2

If he or PO tried this before he connected the jumer wires the fault codes has kicked in. You need the Hammer or Scantool to reset them. Then I'm 99% sure it will work just fine.

Thomas

boxsey911

Thanks Thomas. The PO fitted the bypass but never tried the jumpers at all. The new owner is the first to try them. So I'll tell him that there might be fault codes present and he needs to clear them. Should he do this with the jumpers in place or remove them first?

ThomasC2

It doesn't matter. Just don't turn on the fans/heat before the jump wires are in place.

Thomas

bmohr

well, I was pointed to this thread by Boxsey911 and I can't say thanks enough. Fantastic thread to help me deal with my heater issues. I have a 1990 MY C2, but a 92 engine, so I'm assuming my CCU is the older version. Anyway I'm new to the 964 beast and learning from component to component, system to system so bare with me. Here is my rub, my heater issues are the very same as mentioned here. My CCU fan gets stuck on and runs continuously after engine shutoff. I also have exhuast gases entering my cabin. I figured these were mostly seperate issues but now i'm not so sure. After gleaming info from all the contributors to this epic thread I realized I DON"T HAVE A HEATER BLOWER AT ALL! lol. The PO removed it. Worse, he installed a distributor vent kit, but never put in a bypass duct. The bottom vent/hose port was simply walled off! SOOOOO, could anyone here speculate on if this is my possible source of fumes entering my cabin...or does that still point to cracked heat exchangers? Anyway, i'm going to perform the jumpering when I get home and see how that works.

question: Will i need a hammer to reset the old codes before the fix will work, or can I depress the gas pedal to erase the codes? Many thanks for all the knowledge shared here.

question: has anyone used commercial tubing to manufactor there own duct work/piping? Or does anyone have a used bypass they wish to sell?

- mohrbeers

freedman

No problem that the PO blocked off the bottom vent, thats what the RSRS had done, as they dont need heat at all.

Of course this isnt perfect for a road car so the RS duct is a bit of a compromise as it ducts heat without the heater blower pushing the heat around

http://www.rennline.com/Rennline-RSR...ctinfo/M05.07/

Ive seen a couple of cars that have used flxible tubing instead of the factory or Fabspeed pipes, problem is the fittings at each end

HTH in some way

bmohr

gotcha. Thanks for the reply, I guess I was a bit optimistic Anyway, I actually still get heat in the car, warm enough to feel it coming/blowing into the cabin, which is strange to me since i have no blower fan or tubin to connect the engine fan with the heating duct. hmmmm.

mdowell

bmohr: I have the same setup. Blocked port and still plenty of heat. Since my servos are not 100% this works well for me, with the rear blower the heat was too hot coming out of the drivers side.

kosh

My 1990 c4 blower fan bearings appear to have gone and have blown the 30amp fuse. I can't afford to buy a replacement yet but Winter is setting in here and the car is freezing! So if I pull this relay, jump the two sets and disconnect the blowers plug (can someone please show me where this is, or is it obvious?) my front blowers will start working again. BUT I'm in danger of draining my battery, the relay 'Addition' to prevent this a bit beyond me.
So following just these few stages ive mentioned will I need to reset this CCU?

anto1150

Disconnect the battery, do the entire job, then reconnect the battery. You' ll be OK!

anto1150

The anti-draining relay is another story... I still can't find where to take the 12V from...

kosh

Thanks.
Is there a power lead that has to be disconnected from the blower?
If so where do I find it

Thanks again

ThomasC2

there's a cable on the left hand side of the blower. You'll see the connector if you stick your head in there.

Thomas

kosh

Thanks for your help, I'm going to try and have a go the weekend as we've just had temperatures recorded here of -18c (yes u read it right!!) brrrr

bmohr

just wanted to update I did the jumpering in the relay as depicted and it solved my ills. Also, i measure no battery drain either. CCU fan now goes off after ignition cut off as well. Win win win. Heat, fans, and no battery drain. Many thanks to all those who contributed to this thread.

1990 c2 1992 3.6 engine

tahoelife

I just did the jumpers yesterday thanks to this thread cant believe I had been searching on here for so long to fix this to find this simple answer. So for anyone else looking for a solution to the heater blower bypass or a rs bypass pipe I hope this bump helps them find it easier! Thanks for all who figured this out. I do not know my ccu # but i have a my90 C4 that has been converted to a C2 Again thank you so happy to have front blowers working now I can focus on fixing the servos lol.