ggoodwin

Could someone confirm the below statement to be true / false / probably true etc?

thanks
Garry

On starting the car:
- The ABS light is lit
- The dash backlights are dim
- The heater/demister fan runs slow

On reving the engine past 3000 RPM once, the alternator kicks in and the above symptoms are rectified, however the ABS system does not function on hard braking.

This is a symptom of 'bad solder joints' in the clock!

Rocket Rob

Your symptoms sound to me like your alternator or battery is starting to fail. I would put a volt meter on battery to check. With the engine off, you should have 12-12.5 volts. With the engine idling, you should have 14-14.5 volts. If you don't have 12 volts on the battery, then the battery is failing. If your battery is good but you don't have 14 volts with the engine idling, then your alternator is failing.

By the way, I would also look for any corrosion on the battery terminals and cables.

ggoodwin

Battery does need replacing, but the Alternator is fine - according to the nice AA man.

Found this --> which answers my question. True.
https://rennlist.com/forums/964-forum/315618-pdas-abs-light-on-no-charging.html

Does anyone have a spare - or want to sell me a repaired/working one. I don't have the tools/skills to DIY this.

thanks.
Garry

DaveK

It doesn't entirely answer your question. I've never heard of it also causing dim dash lights (mine didn't) or slow demister - and it shouldn't affect your ABS working either.

ogm

I had almost the same symptoms on my C4. The alternator would now and then not kick in at all before i reved it past 3000rpm. I had the PDAS light and the ABS light on + the emergency light. Resoldered the clock and haven't had the symptoms since.

Odd Gunnar Moe
Norway

Superunknown

Should the ABS light flash when the abs kicks in? Or do you only know if its functioning from the feel of the brake padal?

DaveK

You only know from the feel of the brake pedal.

DJS

Hi Garry,
Not sure about the dim lights but the alternator not kicking in until 3000 rpm is definitely a clock issue in my experience. Does seem a weird link I know but it's apprently due to some part of the clock electrically exciting, or not in this case, some part of the alternator circuit (as you may have realised I'm not an auto electrician!).
I had this issue myself a while ago and rather than re-solder the connections myself I picked up a replacement clock from a 993 (identical to 964 clock) on Ebay for less than £20.00. Only had to wait a week or so until one came up for auction.

Good luck,

David

Lew964

Garry
Strangely enough i re-soldered my clock last night as i too was suffering from the alternator not kicking in untill after 3000rpm. All the symptons you describe, (except your abs problem) are now sorted so the clock can definitely be responsible for the problems you describe. I was like you and unsure if the clock could be the fault but it was so the answer to your question is Yes, its true.
Regards
Mark

Superunknown

Has anyone got any pics of what needs soldering in the clock?

aeroman

Can someone explain to me how the darn clock can bring a fine german engineered car to its knees?

DaveK

Porsche realised 20 years ago that the clock was their most profitable spare part - so the engineered it to be the brain of the car. You think it's the DME - but it's really the clock.

Obviously they forgot about those pesky soldering irons though.

Lew964

http://www.porsche964.co.uk/
The details including photo's can be found on the above site. Easy to follow instructions and doesn't take that long.

Geoffrey

An alternator needs a current draw to "excite" it so it begins to produce power. The function of the alternator light (or battery light) is to draw approximately 250mA of current so the alternator is excited and begins to produce current. The excite wire is also wired to the ABS system and provides 12v power so the ABS controller knows the engine is running.