Gauge Cluster issues

[1984CJ7]

Hey guys, I am having a couple of gauge issues on my 1987 325e. When I first bought the car all of the instruments (minus the odometer) worked, After disconnecting and reconnecting the stereo to do some work behind it, they all seized to function. I was able to bring the tach and temp gauge back to life simply by replacing fuses. The strange thing is, none of them were blown. I just replaced the ones that looked old and added some where they were missing***
Currently the fuel gauge still doesn't work. It is stuck all the way on empty and the light isn't on. Any help would be great!

***note these fuses were missing when I bought the car and the gauges worked then fine before i touched the stereo

[fastair]

My cluster was also working perfect, pulled it and replaced the odometer gears, replaced it and everything was still working. Disconnected the battery to replace a defective alternator and when I reattached the battery cable the tach, temp and mileage gauge was erratic. Someone on this forum told me to clean fuses 10, 12 and 21. I did that and the problem seemed fixed. Later that week I disconnected the battery again and the problem returned. This time I cleaned the fuse connections as well as replaced the fuses. The problem still existed. Was talking with a friend and he said it seemed to him the problem was related with disconnecting and replacing the battery cable. I took the positive cable off, put it back on and all the gauges started working again. I am wondering if I do not have some sort of ground issue. I know I am not looking forward to disconnecting the battery cable again.

[1984CJ7]

My cluster was also working perfect, pulled it and replaced the odometer gears, replaced it and everything was still working. Disconnected the battery to replace a defective alternator and when I reattached the battery cable the tach, temp and mileage gauge was erratic. Someone on this forum told me to clean fuses 10, 12 and 21. I did that and the problem seemed fixed. Later that week I disconnected the battery again and the problem returned. This time I cleaned the fuse connections as well as replaced the fuses. The problem still existed. Was talking with a friend and he said it seemed to him the problem was related with disconnecting and replacing the battery cable. I took the positive cable off, put it back on and all the gauges started working again. I am wondering if I do not have some sort of ground issue. I know I am not looking forward to disconnecting the battery cable again.

That is an interesting thought. I did disconnect my ground cable when I did the work. Ill clean both terminals and see what happens

[Gregs///M]

If your cluster is not refurbished, expect to have many problems. Broken odometer gears, cracked solder joints on main circuit board, dead SI board batteries and transistors are all very common issues with the E30 cluster.

[GrayBeard]

Interesting I have recently had a similar problem with my 87 325i. A few weeks ago, I left the lights on for 3 weeks and the battery was dead (duh) when I tried to start. Not even a dome light on. I got a jump, and it started right up. It kept running, but the speedo, OBC, cruise control and fuel mileage meter didn't work. I drove it about 20 miles, and everything started working again. (?) I figured it was something in the motronic that controlled power distribution. The car restarted that day and several times on days after that. A few days sitting, and it would not start again. Dead battery. After a few tests, I replaced the alternator. It started right up but the same items didn't work. I drove it about 20 mi, and they all started again. Does anyone know why this happens? Is it the motronic acting in the car's best interest, or ?

[wodcutr]

Batteries in the SI board are discharged with no voltage getting to them to keep them charged. After 20 min driving they get some charge and start working but most likely need to be replaced as well. Cluster can have all kinds of issues with bad SI board!