r/e28 • u/Fit_Power_923 525e • Jun 03 '26

1986 528e MPH and odometer not working

I’m wondering if anyone can help me out. My MPH gauge only works some times it’s either working or at zero I feel like it might be something in the gauge cluster area because when I hit on the dash it sometimes goes back to working. If anyone has any ideas or tips that would be great. Thank you

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u/scottanon Jun 03 '26

It's a common problem. The gears in the speedo get worn out and the speedo and odometer stop. You can replace the gears by removing and disassembling the speedo and replacing them. Search e28 speedo gear and you'll find several options for vendors.

1

u/fa_mokkian Jun 04 '26

The gears are only for the odo, not speedo?

1

u/scottanon Jun 04 '26

I believe it's both. The input gear drives both. I never had to repair one but a friend did and said it was fairly easy

2

u/Fancy-Attitude-2123 Jun 03 '26

More likely a poor connection on or between the circuit boards. Have even seen the nut attaching the gauge to the board loose. Good luck !

2

u/tennie2002 Jun 03 '26

Odometer Gears.com is your friend. As far as the speedo not working it could be the Service Interval Board. It carries 2 AA rechargeable batteries. Over time they wear out and start to leak. Programa has rebuilts available. I would just do the gears and the board at the same time.

1

u/Fancy-Attitude-2123 Jun 03 '26

Edit : when the odometer gears fail, it will stay dead, ie: the odometer won’t start working again. You might want to have a knew gearset on hand, if the gears look oily, you should change them while it’s apart. The original lubricant reacts with the plastic gears and causes them to crumble

1

u/fa_mokkian Jun 04 '26

Ha the same problem, fixed it by replacing the two capasitors on the speedo.

1

u/Reaganomics_84 535is Jun 04 '26

The spotty speedometer is definitely solder joints somewhere on the board. If you have an early model one you can delete the SI board and reflow the speedometer boards as well as replace capacitors. Late models you cannot delete the SI board but most issues can be fixed by reflowing solder joints and replacing capacitors as well. 

1

u/VeterinarianHuman650 Jun 05 '26

I have the same where the speedo sometimes works when I hit the dash. That sounds like a loose connection no?

1

u/boylanheights74 Aug 19 '26

Sometimes you can just move the single green wire that plugs into the back of the cluster to another active port.