Gauge cluster problems

[Lof8]

I bought my car with a semi-functional gauge cluster. The tach and temp gauge did not work or light up, but the speedometer and gas gauge worked.

I bought a "working" used cluster and installed it. Now all the gauges light up but the tach and temp gauge still do not work. The speedometer still works and the gas gauge now jumps a lot. The green lights at the bottom are now lit all the time as well. (even with the key out of the ignition). None of those lights came on in the previous cluster.

Now I'm kind of stuck. None of the wires were visibly damaged. Where does the rpm signal come from? and temp sensor? Do you think both of these sensors are broken?

Also, the odometer wasn't working in the original cluster and is still not working in the "good" cluster.

Any help is appreciated.

thanks, Andy

[AdamF 88iS]

Change the service indicator board. There has got to be a procedure for it on this board somewhere, very common issue.

[Lof8]

you think its the SI board in both clusters causing this problem? I was told the new cluster was in perfect order but I guess that isn't guaranteed. Is there any drawback to doing the soldered wire trick to eliminate the SI board? What does the SI board really do?
thanks

[AdamF 88iS]

you think its the SI board in both clusters causing this problem? I was told the new cluster was in perfect order but I guess that isn't guaranteed. Is there any drawback to doing the soldered wire trick to eliminate the SI board? What does the SI board really do?
thanks

Anytime the clusters are left to sit for a long time without being run the SI board can go bad.

The batteries on the board maintain the memory of the service interval indicator. I have no experience with rigging it up some way to eliminate the board.

[ddavidv]

I just removed the SI board completely on my race car. Does it have to be there for some other function? Did not affect the tach/temp gauges on mine.

[Lof8]

Hey David, were any of your gauges having problems before removal of the SI board. I don't care if the SI stuff works, I just want a working tach and temp gauge.

[ddavidv]

The answer isn't simple. I had several issues with this car's cluster when I got it. Every freaking light that could blink was lit up like a Christmas tree. The tach worked when I drove it home, then quit for no apparent reason, and I ended up getting another cluster. However, I again yanked the mini SI board and CHECK bulb from the new cluster and all works as it should. My gauge problem was likely due to the retrofit battery pack installed by the PO in the original cluster.

[Lof8]

thanks for the info. I'll try pulling the SI board out of my extra cluster and see how it goes.

[volgapower]

check the FUSES or whatever they are called, some of them may be damaged

[Lof8]

fuses inside the cluster?

[Jean]

fuses inside the cluster?

I am also trying to fix my speed/odo/cluster problem and in the 3 clusters that i've tried I havent' seen a fuse. There is a fuse that powers the cluster but if your cluster is getting power then it's not a fuse....

Where is c101 plug/connector that people mention ?

[AlpineIS]

I bought my car with a semi-functional gauge cluster. The tach and temp gauge did not work or light up, but the speedometer and gas gauge worked.

The SI board on this cluster is no good.

I bought a "working" used cluster and installed it. Now all the gauges light up but the tach and temp gauge still do not work. The speedometer still works and the gas gauge now jumps a lot. The green lights at the bottom are now lit all the time as well. (even with the key out of the ignition). None of those lights came on in the previous cluster

The SI board on this cluster is also no good. The gas gauge is a seperate problem. Either the grounding nut is loose or the gauge itself is bad. Use the other cluster and you will need a working SI board.

Now I'm kind of stuck. None of the wires were visibly damaged. Where does the rpm signal come from? and temp sensor? Do you think both of these sensors are broken?

The RPM signal is fed form the ECU. The temp reading is fed from a sensor on the t-stat. It is highly unlikely your probelm is related to either.

Also, the odometer wasn't working in the original cluster and is still not working in the "good" cluster.

The cluster in our cars are very, very problematic. You have several issues with both of the clusters, unfortunately. I feel your pain as I have been there. I spent much effort troubleshotting mine and will tell you the following:

The SI boards are either bad on both or need the batteries replaced. The odomoeter gears are broken on each. The later E30s have improved batteries, which held up much better. My batteries are original on my '90. I say use the cluster with the working fuel gauge and find a later SI board OR replace the batteries on either board to see the results. This won't be a guaranteed fix because the board itself may be bad...so you have a 50-50 chance. If you can live without a working odo then use either speedodmeter. You'll have to have the gears replaced if it bothers you enough.

[Lof8]

The only things I care about are the tach, temp gauge, and gas gauge. I'm going to try the SI bypass wire trick and see how it goes.

Thanks for the help, Alpine.

[Lof8]

http://cgi.ebay.com/ebaymotors/BMW-E30-318-325-INSTRUMENT-CLUSTER-BATTERYLESS-SI-BOARD_W0QQcmdZViewItemQQcategoryZ33675QQihZ018QQitemZ280050849197QQrdZ1QQsspagenameZWDVW

check this out

[Lof8]

Shit, I guess the battery-less SI board and board-jump technique only work for '86 and prior. This stuff is retarded.

I thought about making my own cluster out of aftermarket gauges w/ just a tach, water temp, gas, and oil pressure. Is it tough to figure out which wires send these signals?

If some new batteries dont cure my SI board, something drastic may have to happen