[J!m]

Very detailed response.

I am not certain only pulling the air bag fuse is enough to be “safe” but it is certainly better than just ripping into it blindly. The battery should be disconnected and then wait five minutes before starting disassembly.

The TMU (mileage tamper) light will stay out as long as the chip stays in the cluster. I purchased a new cluster (back when you could still get them) from the dealer and the display showed “CodE” and nothing worked. (New clusters need to be coded to the car). I swapped the chip in from another OBD-2* M3 cluster and everything worked but I got the TMU light at that point.

The light indicates a mis-match between the cluster mileage and the DME mileage. I always advise keeping them together. Even if the original cluster is bad, swapping the chip into another cluster will keep the light out.

*The chip should only be swapped within the the same diagnostic version. In other words, don’t put a 95 chip into a 97 cluster or vice-versa. Check 96 clusters carefully, but rule of thumb is: small “M” logo with traction light is OBD-2, and larger “M” without traction light is OBD-1.

Edit- I wanted to mention the light bulbs behind the headlight and fog light (if equipped) switches will be burned out and should be changed while the cluster is out. They are always on and only last a few years.