Speedo stopped working

[zeebedee]

Hi, not sure if related but I’ve changed the seats in my Z3 from facelift to pre-facelift using the BMW seat conversion lead, but since then I’ve noticed the Speedo has stopped working?! Could it be electrical or something else?

 

[NZ00Z3]

It will be electrical.

• Check the Speedo's operation with the hidden cluster tests. In the linked thread there are 2 sets of instructions Post #1 and Post #12. You'll need to work out which is correct for your car. You want the Cluster self test. In Post #1 it is test 2. In Post #12 it is test 1. Make sure the speedo is going full range. https://www.bimmerforums.com/forum/showthread.php?736153-Test-Mode-Hidden-Codes-in-your-car!
• Inspect the speedo sensor on the diff cover plate. It is pushed in? Are the connector pins clean?

 

[t-tony]

Disconnecting the sensor on the Diff. cover and applying some Electrical Contact cleaner spray may help.

Tony.

 

[zeebedee]

Disconnecting the sensor on the Diff. cover and applying some Electrical Contact cleaner spray may help.

Tony.

Ok, thanks, I’ll give this a whirl

 

[Dunkelgrun]

My “no speedometer” problem ended up being a broken or chewed up (mice) wire. The two wires connected to the diff sensor end up connecting to the dash cluster. I pulled the cluster, ran jump wires, and checked for continuity with a multimeter. One worked, one was broken. I ran a new 18 gauge wire from the the sensor to the cluster and it worked again . Maybe a wire got pinched when the seats were changed out?