heater temp stuck on hot, all fans ceased working - ccu help

[A993LAD]

Hi guys,

All the fans have stopped working on my car all at the same time.

No heater fan, no aircon, no windscreen demist - everything suddenly stopped working. even the oil cooler blower under the front wing (which has been a problem because it is always on full) has stopped.

I'm assuming its the ccu - but I've checked the fuse for the ccu unit and it seems fine.

Any suggestions on why the whole unit would suddenly fail and how to fix it will be gratefully received.



Thanks

Marc

 

[decgraham]

Re: heater temp stuck on hot, all fans ceased working - ccu

Hi guys,

All the fans have stopped working on my car all at the same time.

No heater fan, no aircon, no windscreen demist - everything suddenly stopped working. even the oil cooler blower under the front wing (which has been a problem because it is always on full) has stopped.

I'm assuming its the ccu - but I've checked the fuse for the ccu unit and it seems fine.

Any suggestions on why the whole unit would suddenly fail and how to fix it will be gratefully received.



Thanks

Marc

Hi Marc,

Tore B is the expert on all things CCU and I'm sure he will be along soon, but in the mean time I will share what little knowledge I have. First off if your oil cooler fan is running all the time then your resistor is stuffed, the fan has gone into fail safe mode where it runs all the time. You probably know that the fan should run in 2 speeds slow and high, once the resistor is toast (and this is very common on our aging cars) this is the symptom you will need to change that for sure. Regarding the blowers there are two inside the front bonnet underneath the piece of plastic right in front of the fresh air vent, plus you have the blower at the back LHS which takes care of the hot air. Ok what happened to me was I had not a total fan failure but problems with the fan slowing down, any way to cut a long story short you also have relays for the fans as well as the fuses so you need to check those too. You will find one relay in the black box on the LHS inside the engine bay. The relay IIRC is the same as one of the relays form the front fuse /relay box so you can swap around to see if that is the problem. When you open the box it will show you on the sticker which relay to look at.

Good luck and I hope you solve the problem.

ATB

 

[A993LAD]

Re: heater temp stuck on hot, all fans ceased working - ccu

[/quote]

Hi Marc,

Tore B is the expert on all things CCU and I'm sure he will be along soon, but in the mean time I will share what little knowledge I have. First off if your oil cooler fan is running all the time then your resistor is stuffed, the fan has gone into fail safe mode where it runs all the time. You probably know that the fan should run in 2 speeds slow and high, once the resistor is toast (and this is very common on our aging cars) this is the symptom you will need to change that for sure. Regarding the blowers there are two inside the front bonnet underneath the piece of plastic right in front of the fresh air vent, plus you have the blower at the back LHS which takes care of the hot air. Ok what happened to me was I had not a total fan failure but problems with the fan slowing down, any way to cut a long story short you also have relays for the fans as well as the fuses so you need to check those too. You will find one relay in the black box on the LHS inside the engine bay. The relay IIRC is the same as one of the relays form the front fuse /relay box so you can swap around to see if that is the problem. When you open the box it will show you on the sticker which relay to look at.

Good luck and I hope you solve the problem.

ATB [/quote]

Thanks fella,

I probably shouldn't have mentioned the oil blower being on all the time as we've done a bit of work on that and think the problem is identified.

The issue now is that all of the fans have stopped. So if you push the aircon buttons, demist button or turn the interior heater fan knob none of the blowers do anything. Also the heater blower near the engine isn't running either. The temp control has no effect - it's hot all the time.

All of these functions were working fine before and then half way through a trip yesterday they all stopped working. It appears that the ccu has just stopped doing anything at all which I deduced might simply be power to the unit? Having checked the fuse (no. 28? I think) I'm not sure where to try next. Also i wondered if there is a known component in the ccu which dies causing it to cease functioning completely?

The reason I mentioned the oil blower was because I had yet to rectify the identified fault so it was still on continuously but even that has stopped along with everything else.

I'll post on Rennlist as well and maybe try to pm Torre B

Marc

 

[ToreB]

http://forums.rennlist.com/rennforums/993-forum/713326-ccu-complete-failure-why.html
Cheers,
Tore

 

[dw911]

Have you checked that the multi plug on the back of the ccu has not worked loose or fallen out?

 

[A993LAD]

Have you checked that the multi plug on the back of the ccu has not worked loose or fallen out?

Thanks - yes I'd thought about that as my Indy recently had the ccu out to look at the oil blower problem and I know from experience that the the big connector plugs are hard to remove so it maybe they didn't plug them back in fully.

ToreB has given me some useful tips on Rennlist so I'll be pulling the ccu later today

 

[A993LAD]

So, thanks to ToreB I now have the problem identified.

Fuse 1 keeps blowing because one of the heater blowers behind the dash has failed.

Suspect it's the bearings as this seems a common problem.

Anyone on here had to change the blowers and any tips on where to source one? They seem pretty pricey!

At the moment the heater and all other ccu activated kit works provided I don't switch the fan beyond position 2. As soon as I move it to 3 or 4 the fuse blows again.

Do you think I should have a go at removing the blower to try and see the problem with it?

Cheers

Marc

 

[rottenbend]

I'd check to make sure I could source the parts first. Some of this stuff my be in short supply or on back order with the suppliers.