Martin Hodgkiss

Hi,

Can anyone give me some advice. I'm new to the 964.
Yesterday I got into the car and the 'tail' warning light was lit, I then noticed that my speedometer had stopped working!!

On the evening it started working again but this morning it's gone again and the light's back on.

The car's only done 68'000 miles surely the speedo hasn't gone faulty?

One thing to admit.... I'm having a Toad dual bubble Alarm fitted on Monday and I dont want the engineer to bodge any nasty holes in my imaculate dash, so I was probing about for an alternative. In the center console just above the bay of switches (C locking button, hazzards etc) the piece that's carpeted and slopes slightly before going under the dash, seems about right. I pulled the two switch pannels out of the tunnel (they're just held in by spring clips) so I could see if he can get his wires to is as well as make sure its a firm fixing from behind. I noticed after removing the switches a wire comming out of the loom and heading down the tunnel towards the gearstick (maybe the speedo cable on it's way to gear box??). Anyway put it all back together Ok. It's the only thing ive messed with sort of so could it be this?

Thanks!!!

John Boggiano

Non-expert view -

The mystery wire is probably for the handbrake-on warning light switch which lives at the base of the handbrake.

My speedo has done this once or twice. Entirely at random and it's always recovered.

About 1k miles ago, I had the sender unit (on the gearbox on early cars - what year is yours?) replaced. It has failed once since, but does seem much more reliable.

If you need a new speedo head, I think Type 911 do them for a not too ridiculous price.

One quick fix that worked for a while for me was to just disconnect the plug at the back of the speedo head (it just pulls out) and reconnect it.

Martin Hodgkiss

John,

Mine's a 1990 C4

I was hoping that my clock had'nt done enough to be worn out yet. And I would have thought that if it was faulty it would have been faulty from new.

Mystery wire- your probably right.

I'm taking the clock out tonight to see if the block has come loose off the back of it.

Thanks

Martin Hodgkiss

Just looked at back of clock. It's was Ok. reconnected it anyway.

So can I get to the gear box bit?

It may just be loose?? (hoping)

Thanks 4 ur help

John Boggiano

I'm not sure exactly where it is located on the GB.

I think it only costs about £50 to replace, so it's a good place to start.

Martin Hodgkiss

Just started working again!
Got to be a dodgy connection if I only new where the lead attaches to the gearbox!!?!!?

Anyone got a wiring diagram???

thx

John Boggiano

I'm not convinced that the problem doesn't lie in the speedo head itself. (As, I suspect does mine). However, I gather the sender unit is easy enough to access (although I don't know its exact location!) and the connections to it can sometimes be a bit suspect.

If you don't get directions to the sender unit from someone here, try calling Alan or Phil at Tech9 (if you do, please mention my name - it can only help keep my next bill down! ) or GT-One, or probably most specialists who will, no doubt, pass on a bit of advice for free.

If you do find that the head unit is faulty, PorscheApart do a repair service.

Adrian

The speedo sender is mounted on the left side (I cannot get these RUF transmissions out of my head) of the transmission. Access is from underneath. I frankly do not think it will be the sender. Your problem is most likely the speedo itself. I know it is the last thing you want to hear but these types of speedos have a life of around 10 years. Based on my little experience with these problems you are looking at 8 speedos, 1 sender and 1 wiring problem per 10 failures.
Ciao,
Adrian
964C4

Martin Hodgkiss

Thanks for your help guy's, if it hapens again (which it probably will) i'll look into the speedo side first.

Thanks again

Martin Hodgkiss

.....No its stopped again.......

.................Hold on after a few miles...... It works again......

..no its gone

John Boggiano

I look forward to the solution, as mine is not far behind!

If only it stays broken, check out that Porsch-Apart service - Tel. 01706 824053

Martin Hodgkiss

Works again!

Ive found that after about 5-10 miles it starts working!

Damn weird... got to be a connection (mutter,muttter,mutter!!)

BLUE C2

I had exactly this problem. Sometimes worked sometimes not, usually OK after 5 miles or at speed.
A new sender cured it completely.
On my 1989 C2 the sensor is on LHS of g/box near drive shaft output. Held in by a little retaining plate and 2 fasteners. Needed to remove one of the support stays as well. Cost £54 from OPC.
Hope this helps.
Blue.