decampos

A couple of days ago I replaced the dash and pod. The speedo now doesn't work. It would seem seem likely that something happened during the swap but it may just be a coincidence. I'm pretty sure the speedo still worked when I next took the car out. Today however, it's dead.

A couple of questions for the experts: I noticed that there was a 4-pin barrel connector just hanging loose, there's no matching plug for it. Does anyone know what this is? There's another larger connector (next to it, taped up) that looks like the same kind of socket for the lights/hazard/heated screen etc. Anyone one know what that's for?



I checked the wires in the spare wheel well. I can't see anything looking suspect apart from two thin white wires. I don't think they are wires, they're more like string. Anyone know whether this may have something to do with the non-functioning speedo?


I know this connector is unattached! I was thoroughly cleaning it with contact cleaner.

I double checked the cluster to make sure everything's seated correctly. Everything appears fine. Any pointers to what this problem may be is very much appreciated.

(1983 car)

AirtekHVAC

I would guess odometer gear. They get crumbly after a while

Lizard928

The 4 pin connector is for cruise control.

The 2 wires visibly connected being green and brown are the speedo wires.

it is likely a dirty contact on the back of the cluster.

decampos

Thanks for your reply Lizard928.

That's interesting. There doesn't appear to be anything that plugs into this. I'll investigate.

I'll explore this further. I did clean all the contacts in the back of the cluster when I had it all apart. Could I have disturbed anything else during the pod swap that could account for the non-working speedo?

decampos

Just an update. Took the car out today and the speedo was working again. On the way home, it's back to being broken. So, it's an intermittent problem (my favorite type).

1989porsche928

i noticed my mph guage would jump up and down on turns, anyone with the same problem? i replace my spedometer sensor.

Lizard928

The cruise control connector comes from the stalk. It is just below the turn signal lever. I've only seen 1 928 that did not have cruise. But I suspect all the wiring is there.

The problem is likely at the PCB to the board which has the 5 or 6 pins which go through in to the speedo.
The circuit traces are connected via rivets, the rivets corrode and the signal then doesn't go through.
I take a powerful soldering iron, make it nice and hot and get solder to attach to the rivet, and run to the PCB so that there is no area for the power to break. (sanding the rivet first does help with solder adhesion.

Lizard928

I also wanted to mention,
in your picture you show the 6 pin connector disconnected. While it is apart use an awl and crimp in the female portion of the pins slightly to give better contact.
I normally use an electrical cleaner as well, and then put a dab of dielectric grease on the pins to help prevent problems in the future.

decampos

Thanks again for the great advice Lizard928.

Wisconsin Joe

The speedo problem may well be the rivets as Colin (Lizard) suggested.

Mine did the same thing. I repaired it following Dwayne's writeup. Basic soldering techniques are required, if you don't know what you are doing, practice on something that doesn't matter first, or get help.

Dwayne's writeup:

http://dwaynesgarage.norcal928.org/I...epair%20II.htm

decampos

Thanks for your reply. I have explored that site. Lot of interesting info there.

decampos

I took the cluster apart. Everything looked perfect so I didn't do the solder trick but I meticulously cleaned everything with contact cleaner. The speedo is (currently) working again. We'll see if stays that way. Thanks again for the help.

GerritD

I had the same problem, I checked the rivets and saw nothing abnormally even after cleaning. However I still got intermittent speedo.
So I decided to solder every possible rivet linked with the speedo.

It did the trick !

So please solder.

kr
Gerrit

decampos

Thanks for your reply Gerrit. I just couldn't bare to do it as it looked completely perfect. The speedo still hasn't reverted back to its broken state so I'll hold off soldering until it dies again.