Cluster issues, First Odometer, then Speedometer

[jlevie]

I'm not convinced that you have located the speed sensor wire...

[BROKINBIMMER]

I would take the cluster out and exam the board for any crack in solder under a magnifying glass. These boards are old.

+1

I thought for sure I thouroughly checked all the connections for any cracks, and sure enough I found one after looking at it with a magnifying glass. But...My damn odo is STILL not working, even with new gears!!

[P Arkus]

I'm not convinced that you have located the speed sensor wire...

Can you explain what the speed sensor wire looks like? From my research, I realized the pics I posted are just a wire for the Cruise Control, and that the speed sensor goes into pin 12 of the white connector and the ground is pin 8 of the white connector. So if this is the case, the speed sensor wire would be plugged in along with everything else in the white connector harness.

Am I correct or am I still completely missing something? I've tried googling pics of this wire and am still coming up with nothing!

[jlevie]

I should have checked the ETM for this car...

You are correct. The speed signal is via C2. So either the speedometer is bad or the speed signal isn't reaching the cluster.

[P Arkus]

I should have checked the ETM for this car...

You are correct. The speed signal is via C2. So either the speedometer is bad or the speed signal isn't reaching the cluster.

Ok perfect. At least this narrows it down for me a bit further. Also last night I took out the plug at the differential, cleaned it and put it back. Still no speedometer. I'm thinking its just the speedometer thats bad. Really need to find another one I can quickly swap in to test out!

Sorry for the noob question, but whats "ETM"?

[jlevie]

The ETM is factory wiring diagrams.

[Northern]

For anyone having a speedometer issues, it may be worth your time to check the connector at the diff for corroded pins and corroded/severed connector wires. Both of my e30s have had speedometer issues caused by the connector and wiring at the diff.

[Gregs///M]

Speed signal from the diff sensor is brown/red in the C2 connector (white.) Blue/yellow is the wire that plugs into the green connector, this is for cruise control speed sensor signal input to the cruise control module. it is not necessary for the blu/yel to be connected for the speedo to operate.

Since you are experiencing no odometer or speedometer, it is safe to say there is no speed signal entering the cluster. However, crack solder joints on the cluster main board could be the culprit.

Probe the brn/red wire with a meter on AC volts or a test light. You should see a pulsating signal that increases as wheel speed increase. You should measure 1.5-6 volts AC while the wheels are spinning. If you confirm this at the cluster connectors, your cluster main board will most likely need to be re-flown with new solder.

[P Arkus]

Just thought i'd update this thread. Unfortunately I had no luck in finding the problem, all I know is it must have been the speedometer. I swapped a different cluster in and all works fine. The problem is now solved, I just wish I knew exactly what happened to the speedo to make it crap out on me :(