Porsche Enthusiasts Club Forum

Hi
I've just bought the car I always dreamed of,
A 928 S2. It looks and and driver great.
I'm now working my way through the electrical bits that don't work !
Nearly there, just two more to go but need a bit of help.
The first is that the indicators don't make a ticking noise, or rather they do but
you can't here it behind the wood and carpet on top of the fuse box, is there a sounder
somewhere else ?
The second is the Cruise control. I don't know where to start with this one, are there any
obvious places to start ?
regards Ade

My indicators are the same, no discernable sound, but I don't know if that's normal.

No ticking except the relay - in their austerely correct way Porsche expects you to notice the flashing arrows!

What's the problem with the cruise? Mine works fine but I must say I almost never find circumstances in UK where I can use it.

Many people have returned cruise to working order by resoldering the pcb (solder joints fail over time). The cruise is behind the radio, bolted to centre tunnel at firewall (big aluminium box). To get at it you have to remove both carpeted sides of console and removing parcel shelves will give you better access too.

With the brain opened the circuit board had scores of solder joints. You should just remelt these with an iron, and add extra solder to those where solder has obviously shrunk from joint. Don't heat for longer than it takes to reflo joints, esp at IC pins.

I think your S2 has vacuum control of cruise so you need to check workshop manual for relevant tests which are detailed. There is also a thorough section on testing the cruise brain but resoldering will cure a lot of any faults found so try this first.

Thanks Stratfordshark.
I guess I can cross he indicator thing off the to-do list.
There is some clicking coming from a relay somewhere when I try and use the cruise control
but nothing happens. I will have a go at the control unit as you suggest.

Hi

Thats all excellent advice...BUT...I did all the "resoldering" the brain thing, then swapped it twice, then checked the HUGE system of cruise control vacuum pipes on my S2....

I also bought a brand new arm unit for the streering column...

Soooo....several MONTHS later and probably 40 or 50 hours of labour.....

I gave up....it just wasn't worth the hassle, so I removed the brain totally and never missed not having a cruise control....lol

All the best Brett

Hi

Oops forgot to add...the Indicators ONLY CLICK quietly at the relay (under passenger floor)

All the best Brett

Good story Brett. Maybe I'm a weird driver but while I have enjoyed having cruise in the USA - and even France - I've rarely experienced road conditions in the UK where it was safe to use. maybe middle of night on deserted m-way, otherwise as you say never use it. Shame as it's a well thought-out, ergonomic system on 928.

Hi Adrian

The story gets better....

Whilst in the middle of trying to figure out what was wrong...

I asked my local OPC what they would charge to fix it...lol

They said.....up to £2000....when I asked how they worked that out , they said, well first we will change the brain for a new one (around £700 at the time) then if its not that we start changing other bits.....I said....presumably if its NOT the brain you put the old one back in ? They said no we MUST leave it in and charge you for it even if its not that lollllll....at that point I lost interest

All the best Brett

Brett
I guess I'm not that bothered !
I probably would not use it anyhow, a bit like a radio in a 928.
But it would be nice to have everything working as it should, so I will have a go at the brain
if it doesn't work then I will probably call it a day.
I find the lack of indicator sound really annoying I'm sure it must be possible to rig something up, another project
I think.
Regards Adrian

Think I need a new "brain" !
Took the cruise control brain out and did some re-soldering.
The Cruise control now works except it holds the speed for a short while
then starts accelerating on it's own.
Trouble is my air-con is now not working I must have dislodged a wire or conection in
he dash somewhere so now I have no air-con and cruise control
is still not usable joy !

You probably pulled the connector off the back of the aircon button if you were working in that area. That happened with mine the other week.
I've seen these cruise control "brains" on ebay for reasonable money, you could try a second hand one in it?

That's funny from the OPC! I've got a receipt in the history file on my S4 where a previous owner has clearly bought the car, then booked it in to have a few little faults sorted out, and the resulting bill was over £2,000.
I'm sure there are tear stains on the invoice.

Is the aircon light not coming on? If that's case then as suggested you have probably pulled out connector from back of aircon/central locking strip mounted underneath heating controls. The connector at other end is to a molex-type plug and these are quite hard to undo unless deliberately.

If the light works but you're not getting cold air then you have probably pulled off one or more vacuum lines from the manifold which sits just in front of the cruise control computer. On the driver's side you'll see 5 coloured vacuum lines and one black line feeding this unit - should be obvious if one is disconnected. Make sure it's pushed firmly home in relevant rubber elbow connector.

Latter more likely if you also notice loss of function of heating/ventilation in addition to no aircon.

Brett

That sums up OPCs wonderfully.
Its is a great way to maintain your car if one can afford it.

Stephen

Thanks Stratfordshark

The AC light comes on so probably the vacuum tubes. It was a struggle getting the
cruise brain out. Adrian

Hi

I've had a look and everything looks OK.
I've had a thought , it might seem like a daft question but
is there a definite change in engine noise when the Air-con comes on ?
Thinking about it before there was a lot of air noise from the central vent when it came on
which seemed intrusively loud. There is a change in the noise from the vent now but it is much more subtle
I'm wondering if when I had the heater control out to fix a broken button I actually unintentionally unjammed a
stuck vent flap or something. It's a bit difficult to tell if the air con is blowing cold air at the moment due to outside temps.
Adrian