l.chadburn

I have had my heater CCU repaired in the US and it has just been returned in working order with a life time guarantee.

I plugged it in the car and it now lights up as expected, only I still have the same problem.

WHAT DO I CHECK NEXT.

When I turn the ignition on I get front and rear fans on, on full and cannot change that.
When I turn the ignition off and pull the key out it carries on and i have to full fuse 1 to stop them.

Lee

Rocket Rob

There was a wiring change in 1991 for the CCU harness. It allows you to use a 993 CCU. What year car do you have and what model CCU?

Sorry if this has been asked before. If you have the link to an earlier thread, please post it.

l.chadburn

I have a 92 car and the unit is the non aircon unit with a 964 part number.
Checked that and i think I have a unit that should work

cheers lee

boxsey911

The last time I saw that behaviour from the fans it was the final stage relay at fault. I have a spare which I think is good - pm me if you want me to post it for you to try.

l.chadburn

Cheers mate,

I have a spare my self I think. It is the one on a metal plate which fits just in front of the servo's.
I'll give it a try and let you know what happens.

Lee

boxsey911

That's the one. I remember you saying that you had picked one up but I guess you haven't changed it yet.

l.chadburn

Steve

Just fitted the other final stage relay that I had.

Made no difference what so ever.

either thats faulty as well or where do I go from here? any ideas

lee

boxsey911

Of course, the second hand one you bought could be a dud but let's forget about that now because what concerns me more is the other stuff i.e. the CCU doesn't appear to be giving you control of the servos or the fans. What is the part number of your CCU? As Rob mentions, there are different ones...a non aircon, RHD 964 made in 1991 or later should have unit 964.659.046.01.

The reason I'm asking this is that your car may not have the original CCU because the original could have stopped working a while ago and the PO may have swapped it for an incorrect unit.

l.chadburn

My car is a 1992 and has this part number on the CCU

964.659.046.00

Lee

Rocket Rob

I think we may have found the problem. The 1991 and new 964's need a CCU of 964-659-046-01. Do you have access to another 964 where you could try swapping CCU's?

boxsey911

The later cars had a small wiring modification to the plug. I wonder if removing the wiring modification from a 92 car will allow a pre 91 CCU to be used with a later car?

To check if you have the wiring mod on your car remove the plugs from the back of the CCU and open up the larger 35 pin connector. The wiring mod for later cars is identified by there being wires connected to pins 19 and 1* (they're next to each other at one end). Pull out the wire in pin 1 and tape it up and plug your CCU back in and see if it works.

This is only a suggestion of what I would try in your case...I have no idea if my logic will work...but have my fingers crossed for you.

*ealier cars that use the 964.659.046.00 CCU only have a wire in pin 19.

l.chadburn

Rob - unfortunately not, I dont know any one else with a 964.
The only other thing I could do would be to visit the local breakers in leeds to see if they would allow me to try one.

Right i'm off in the garage in about an hour to try the wiring idea.

will let you know.

cheers for all this guys

l.chadburn

just had a try - do the wires just pull out?

lee

boxsey911

I've not done it myself (because I've no need) but Adrian Streather's book shows a small flat blade screwdriver being used to push the wires out from below?

So I guess you have indeed found a wire in pin 1?

l.chadburn

tried it - no change unfortunately.

guess I need to get hold of a 01 part number or the 993 version to see if it makes a difference.

Suppose I could always sell my unit. I suppose it would be a good buy as it now comes with a life time warranty.

lee