mshobe

Please check out this quick video I shot; the only sound you hear is the very strange buzzing noise coming from either my clock or perhaps my climate control unit — I really can't tell.

The video description: "From my '89 Porsche 911 (type 964). This noise just started on really cold days in the winter. Seems to go away once the car warms up, but until then, curiously, it continues even after the ignition is cut and the key is out."

Anyone ever seen/heard something similar? I don't want to go tearing gauges out of the dash unless I really, really have to.

LouZ

??? odd buzz - since it continues AFTER the key is out, look at the climate control fan in the rear of the CCU.

I would suggest removing the clock as that is the EASIEST gauge to remove. That should give you a quick reference as to where the buss originates.

To reinstall the clock gauge, just use a bit of soap liquid on the outer edge.

Keep us updated.

mshobe

climate control fan in the rear of the CCU sounds like a candidate; didn't even realize it had one. One easy way to test that would be to pull the fuse for the CCU entirely, wouldn't it? Maybe I should attempt something similar for the clock/gauge panel if the CCU fuse test doesn't reveal the culprit. #11 controls the clock, #28 the "control unit" (does that mean CCU?)

dave-C2

I had a similar buzzing and it was caused by a loose ground wire at the back of one of the wire bundles that clamp into the back of the CCU.
It's easy to remove the CCU from the dash using the radio removal prongs and if you don't pull the CCU out too far you will be able to check wiring connections on the two terminal clamps. If you do pull too far without unlatching the connector strips you may very well loosen some of the connections - ask me how I know.
Ground wires are brown and IIRC there is at least one per terminal strip. In my case the culprit was near the end.
BTW, credit goes to Loren for diagnosing my problem, but don't blame him if my suggestion is wrong.

Rocket Rob

The CCU is powered by fuse #1. The reason I know this is that I have spent the last 3 weekends troubleshooting a high current draw and have isolated the problem to the CCU.

boxsey911

Yes same in mine. I'd heard it was normal and nothing to worry about but might investigate further, given the replies above.

HiWind

did you guys ever work this out ... confirmed as the ccu fan?
other forum 1
other forum 2

its seems it must be ... off after about 15 min ,,,, takes varying time to shut off ...
had me worried there for a mo - side affect of working late at night in a quiet place lol
things starting getting 'strange' ...

(was worried the fuel pump wasn't switching off .. gladly it isn't that)

cup997laurent

Didn't saw your video , but i had a noise in my 993 tt climate control, which didn't stopped when ignition was off. I changed the unit and the noise was off. It seems to be a faulty sensor in the unit, so the small fan is working too long and it comes noisy . Don't know if you can have it repaired, if not , a new one is not cheap.
Merry Christmas...

HiWind

thanks Laurent!

nine11speedster

i know this is an old thread, but I was able to locate where this strange buzz came from. I hope this photo helps whoever is having the same problem.