WICruiser

Some of you have seen my thread regarding a speedo problem. It appears to be a problem with voltage drop through the CE panel.

I confirmed full battery voltage (12.4 v) at the connections on the top of the relay/fuse panel but I only see 11.7 v at best on the feed side of the instrument cluster fuse, and I am down to 10.4 at the baterry voltage connector for the instrument cluster. Bottom line is I think I need to pull my panel and give a good cleaning.

I tried removing a few of the wiring connectors (A, B, C, etc.) along the bottom of the panel and they seem to release from the top but not the bottom. Is there a trick to getting the connectors to release, or are they just tight from being installed for 25 years?

I seen several posts regarding cleaning the panel connections and will do some searching but if anyone has a preferred method please point me in the right direction.

Alan

Pull the red tab in the middle at the bottom - Its the release tab...

Alan

Jadz928

Alan,
Do you know what year they added the release tab? I'd like to make a mental note of that. Thanks!

jpitman2

I would suggest its more likely to be bad contacts on the pod panel. The early connector metal parts are quite soft, and probing with a multi meter pin can bend them out of contact. I had to re-tension the contacts in the 3 hoods on mine recently. Plus the dirt and corrosion issue also.
I assume you are seeing the make/break cycle at the CE board when turning a back wheel OK?
Anyway, Snakeskin has a very good article on how he cleaned his CE board - look for that.
jp 83 Euro S AT 54k

Jadz928

Snakeskin, that's funny. Look for that and you'lll find yerself a pair of boots from the Bayou.

Sharkskin's CE panel R&R

jpitman2

OOps!!!
jp

WICruiser

jp - I am seeing the make/break cycle with wheel rotation. Unfortunately I am only seeing about 8 volts at either connector in the spare tire area or the CE panel that feeds to sensor.

Alan - does the red tab pull straight back? How hard should it be to pull? I don't want to break something in the process if I can avoid it.

Sharkskin's panel had the older bullet type fuses, mine has the blade type. I understand from a post I found that the panels are entirely different but regardless that removing the rear wires is not recommended. My current plan is to remove and clean with Deoxit, if nothing ese because it can't hurt.

How do you tighten up the edge connectors on the instrument cluster?

Alan

85 and up have the newer (bigger) panel with the release tab.

Pull it straight out from the panel towards you - firmly - if its tough - re-seat all the plugs back into the panel (push in) then wiggle the tab in & out until it unlocks. The bottom rail that locks the plug lower tabs slides sidways to release when you pull the tab (you can help it slide a little too).

Alan

jpitman2

Not sure if a blade fuse CE board implies different pod connectors or not - I know S4 pod connectors are different. The pod connectors have curved split metal blades to make contact with the copper traces on the mylar fiilm over the PCB edge. Looking into the connector from the pcb board side, with a thin pointed object (I used a pointed Exacto blade, something thinner like 1/16 piano wire might be better), bend the blades in the direction they curve as much as you can. ie, if they look a bit flattened U shape, bend the bottom of the 'U' MORE. I had a fuel gauge that pegged when lights were turned on, as I had lost the grounds on the right connector, and the only available ground was out through the fuel gauge. Probably good the give the outside of the U a bit of a clean with something lightly abrasive first.

Speedo - do you have good continuity from the CE board to the speed connector in the spare wheel well? Do you have measurable resistance across the speedo sensor when its closed - unlikely as its a sealed reed relay, but not impossible. Unless you have ABS, when the sender is part of that setup IIRC.
jp 83 Euro S AT 54k.

WICruiser

Thanks again - I hope to get back to this on the weekend and will update when I have more information.

WICruiser

I have had the panel out twice now, not nearly as intimidating the second time.

The terminal connections did not look bad but I cleaned all of the face plug connections, relay sockets, and fuse sockets with Deoxit. I also cleaned and "adjsuted" the edge connectors for the cluster.

Unfortunately I still only see approx. 8 volts in the sensor circuit measured at either the CE panel or the connector in the spare tire well area.

The ground connection from the cluster is good.

In the wiring diagram they show a speed warning buzzer, but I can not seem to locate it. I would like to remove the buzzer just to confirm it is not creating the problem. Any insight where it is located would be appreciated.

Roger

underdog928

Roger:

I had a similar problem on my '85. In addition to cleaning and deoxiting all the fuse slots, I replaced all the fuses with new ones and that fixed all the low voltage problems I was seeing at the cluster, voltmeter and cigarette lighter.

Looking closely at the fuse tabs, they were all corroded, some so bad that they were black.

HTH

Alan

Speed Buzzer is a regional option (Saudi Arabia primarily I think).

I presume the way it works is this. The Saudi government requires it on all new vehicles, Porsche installs it and then the owners pay to have it taken back out after delivery....

You shouldn't have one

Alan

jpitman2

Funny thing I heard while in Saudi relates to speed chimes...Range Rovers came in with speed chimes that came in at 120kph. One owner came back to dealer and had the chime disabled. A few days later he called and said his car had locked him out - wouldnt open on the remote or the key. Dealer had to go and do something to get him going. Subsequent research found that this lockout occurred only if you disabled the chime in the English menu of the chassis computer management tool - if you did it in the French menu, lockouts didnt occur.

jp 83 Euro S AT 54k

WICruiser

Oh well that is another idea shot.

I have had all the fuses out and the only one that looked at all suspect was the one for the read defrost. That being said I will go through all the related circuits and replace fuses and see what transpires.

Thanks for the suggestions.

Roger