gauge cluster acting strange

[mario23_15]

When I start the car, the tach sweeps to 7000 rpms and stays there until the car warms up then it'll bounce around a bit, then falls to zero and stays there acting as if it doesn't work at all.
The speedo and fuel gauges don't work at all.
The temp gauge seems to work fine.
Any ideas on what's causing these cluster problems?
Here are a couple pictures. The first shows the tach at start up


This is after the car is warm

[reelizmpro]

Pull it out and check the tach and main pcb for shorts and breaks. How are the si board batteries? Looks like an 84 318I cluster.

[Gregs///M]

You most likely have leaky batteries that has caused the logic to get all wonky. You'll most likely need to replace the cluster and if your lucky, only the SI board.

Also try changing fuse 10, 12, and 21 and some of your gauges might work again.

[mario23_15]

Thanks for your input, guys.
I changed out the fuses first and still nothing. So I decided to tear into the cluster. Here are some pictures. Overall, I believe the board looks good (to my untrained eyes of course).


I'm assuming the 94-07 is the expected life on the batteries? So they're most likely dead.


I then found it was a motometer board in a vdo cluster (not sure if it really matter)

[Gregs///M]

Well you have a modern SI board in an early style cluster so that is great. You probably just need to replace the SI board batteries.

We have these boards in stock, ready to ship. Just pay for the core price and it will get refunded when you return your original SI board.