Koenig-Specials 928

Both Speedometer/ODO and mileage functions stopped working a while back.

All grounds have been cleaned.
All connections to the dash pod cleaned with eraser and cue tip.
Banging the dash no longer works

I raised the rear wheel and with the meter set to make noise I got the on/off signals that the pulse generator is working.

I want to check the wires to the CE Panel.
I read that they come in at T1 & T2.
Can you tell me where on the CE Panel I can find them?

The wires at the wheel well to the CE Panel are both Brown/Red stripe. Correct?

Please and thanks

Koenig-Specials 928

Also fuses 10, 24, 25 & 39 checked ok incl pulling out and replacing with new fuses

Wisconsin Joe

"Banging on the dash no longer works"?

Did it used to?

If it used to work by banging on the dash, then that's where I'd start looking.

Dwayne has a great writeup on it, but I can't get the site to open. I hope it's not gone.

Short version: There's a hard circuit board under the plastic one behind the speedo. There are a couple of rivets that go through long pins that go into the speedo. Those carry the signal for both the speedo & odo. They develop corrosion and lose connection. They can be soldered to restore the connection.

Koenig-Specials 928

Thanks WJ

Last week I cleaned all of those rivets and they felt secured.
Then I put the pod back together, the speedo and aux all worked for 3 days and then back to square one.

So I am trying to ensure all the wires from the back to the front are properly connected before taking the pod back off.

Koenig-Specials 928

Bump.
No one?

Trying to find the 2 wires from the spare tire well to the CE Panel.
Please and thanks

Majestic Moose

Location circled in red.

Attachment 1106857

Koenig-Specials 928

Thanks Alex.

Now I need to find where they come in to the CE Panel

Randy V

My speedometer recently stopped working.

In trying to track down a suspected voltage drain I pulled and reinstalled all the fuses and relays including Relay XIX (on 91-95 models) that controls the speedometer.

After noting the speedo issue I went back to relay XIX and pulled it, reinstalled it, thinking that would correct the issue.

It didn't.

I also checked the connectors in the hatch area and all were in good condition.

There is no fuse on the speedometer circuit that I can determine.

Could the relay have perished when I first pulled it?

How to test if it is indeed good or bad?

Thanks,

Randy V

Any guesses?

Koenig-Specials 928

Wow, another 928 with the same injury.
Mine went from working perfectly to not working after I changed the dash lights 5 months ago.
That included the odometer and trip info as well. So far I've checked the pulse generator and cleaned the connections at the battery area and at the dash plug #4. Nada. So I decided to change tactics and cut the green and brown wires coming from the pulse generator and connected them directly to the ones going to the CE Panel (I bypassed the connector). Now everything works 50% of the time so I did get some success).

I am now trying to find these 2 wires at the CE Panel and in an earlier post in this thread I asked if anyone knew where they were but got no responses. So my battle continues. I believe my problem has to do with weak connections along the way to the speedometer. All my grounds were cleaned and recleaned.

Hope you have better luck than me.

bureau13

I have this same problem post-pod repair. One of the things I did was fix the odometer gear, and another was resolder the "rivets," as my speedo was flaky. Now it's not flaky, it's completely non-functional! Of course, for me the most likely cause is that I screwed something up while 'fixing' it, but I haven't re-pulled the pod to check it out yet.

dr bob

Randy's car is a 1994 GTS, which uses one of the ABS wheel sensors to generate the pulses that the speedometer needs. No pulse sensor, connections in the spare wheel well, etc. Instead, the relay XIX, labeled "FCU", is a signal conditioner. The pulses to the speedo from the pulse transducer reference ground when "true". From the ABS unit, it's likely that the pulses are pulled high when true rather than low. I'm guessing (and no more than that...) that the FCU is not a lot more than a transistor (or FET) and a couple resistors that invert the incoming positive pulses so they read negative at the speedo unit.

Randy--

Best diagnostic is with an oscilloscope. Look for (or simulate) the positive pulses and see if the signal to the speedo is correct.

Reference C23 for the speedo connection (labelled "SPEED" at one of the pin 6) and G72 (ABS unit pin 12)

Randy V

At this point I just want to test if the dedicated relay is good or not.

Suggestions how to test it?

dr bob

Randy--

Best diagnostic is with an oscilloscope. Look for (or simulate) the positive pulses and see if the signal to the speedo is correct.

Reference C23 for the speedo connection (labelled "SPEED" at one of the pin 6) and G72 (ABS unit pin 12)

This is the in-circuit test method. There may be some frequency-divide or multiply functions in there too. You'll know when you compare the simulated ABS signal with the pulses sent to the dash display.

Randy V

Yeah, no access to an oscilloscope.

The relay can't be tested using a basic continuity test?