Blinking OBC?

[325e '87]

I bought a working 6 button obc to replace the broken one in my sons 325e. When I plug it in and turn on the ignition I get a quick flash of 12:00 and it flashes at maybe a 5 second interval, it’s a consistent interval that goes on for a few minutes and then I get nothing.

both lights work and dim/bright properly

im really lost trying to figure out what to do. I’ve reseated the 21 fuse and when I put the obc in my car it works fine.

[superj]

Do the obc have a colored plug on the back? Like something you can swap

[325e '87]

It’s a green connector, maybe 12 pins? The car side is female, obc is the male

[superj]

I would geuss just check the plug on the back of the gage cluster and see if all is tight? That is where part of that plugs in