gmorat

Badly burnt out. The smell Is pretty bad.

Hopefully when it's rebuilt all will be well.

Blargh!

phoneyman

If the rebuilder is able to tell you what likely caused that burn, could you post it up? I dont know much about the CCU but havent seen this on Tore's blog (i dont think) and it looks like its away from power components.

ToreB

Wow, that's quite a damage. I have never seen that before!
It would be very interesting to find out what component that failed.
Cheers,
Tore

Aussie Alan 993

That looks expensive...

Have any of the electronically gifted folks here ever developed or considered developing a CCU that is micro processor based, it could be made to work like a more modern climate control system and be a bit more robust and be programmable via USB. It could have a digital readout or even interface to a smartphone if you get really fancy.

I dream but I am sad to say that I have no ability to comprehend electronics well enough to pull that one together but I'm sure someone here does, or knows someone who does.

gmorat

As soon as I hear from the rebuilders I'll let you all know. Should get there on Monday and hopefully it won't take them too long to figure out what it'll take to fix it and hopefully what caused it in the first place.

Aussie Alan 993

Out of interest, did they indicate the cost to repair or is it too early to tell?

Dryfly57

Hope it works out gmorat!
Let us know what gives.

ToreB

gmorat, it would be of great help if you find out what component that failed. It could be vital information, if it's a fault elswere in the car, you could end up reinserting the CCU and the same happens.
I'll assist in any way if necessary
Cheers,
Tore

Aussie Alan 993

Tore, That is great advice about understanding the root cause of the problem, no wonder you are the guru of the CCU (amongst other things electronic).

Is my idea of a modernised CCU feasible in your opinion?

Cheers
Alan

ToreB

Alan, thanks.
Making a new CCU design would be a costly affair, and one would have to be sure of the sales potential. I don't think it would be a very popular item, and I can't really see the need for bells and whistles on this unit. Also, making a better (or equally good) heat regulation algorithm based on reverse engineering would be an difficult, if not impossible task.
Cheers,
Tore

JB 911

It would be nice if one of the many fuses in our fuse panels would have failed first. I wonder if a fuse installed inline closer to the ccu could have prevented this. The cause will be interesting. Did this all start when you pressed the defrost button a couple of weeks ago in the other thread? Maybe that was the awful smell you mentioned?

Aussie Alan 993

I read a while ago about the wonderful and complicated things that can be achieved with the Arduino platform and thought of this as a possible application but I have no concept of what the level of difficulty is because it is all difficult to me. Now I know, thanks.

Alan

ToreB

I agree, the Arduino platform is a very good starter for people that would like to get aquainted with microcontrollers. However, The CCU contains a Siemens/Intel 80515 microcontroller or equivalent depending on version. It's not that different from a Arduino, and I think the Porsche/Bosch/Hella engineers have wonders with it already :-)
Anyway, we're hijacking the original posters t topic.
Cheers,
Tore

gmorat

It certainly did and it certainly was! This unit stinks of burnt plastic. The fault looks like it started on the small board attached to the faceplate just behind the fan control **** though when this happened I hadn't turned the **** directly but pressed the defrost button to clear the windshield.

As to why a cheap fuse didn't burn out but an expensive component did I have no idea. I have driven the car for 6000 miles since I bought it and have used all of the functions on the CCU many times and yet in the rain on that night this happened.

I had the car in for servicing and no other codes were present on the car apart from an O2 sensor that needed to be replaced and had caused a lumpy idle.

As it stands at the moment the rebuild service is $325 from some outfit in TN but that may change when they inspect the board. I'm hoping they have a better understanding of what went wrong so that I can insure it doesn't happen again.

As I said, the unit itself was relatively new and had just been replaced less than a year before as the original was uncovered to be non-operational in the PPI.

G

Lorenfb

"As I said, the unit itself was relatively new and had just been replaced less than a year before as the original was uncovered to be non-operational in the PPI."

That doesn't sound encouraging! As has been indicated many times to Rennlist
members, the 964/993 CCU is very reliable and rarely if ever fails.
Many, including some Porsche dealers/independents assume the CCU is the source
of their 964/993 climate control problem, when in fact it's usually something
external to the CCU. Read here under 'Porsche CCU 964/993';
http://www.systemsc.com/problems.htm

Given the extent of damage indicated in the picture, most likely the main circuit
has major damage too and a problem external to the CCU is the cause.