Installing 13 button OBC have some issues.

[motorsports_3]

My car comes stock with a 6 button OBC. Do I have to swap out the blue harness or could I use the one already coming from my car?

Second question is what if I have a coding plug from a 325i in the obc and my coding plug is from a 325e in the cluster.

Edit: So my car is an 88 325e. My cluster came from another ETA, not sure of the year but I swapped the coding plug, and the obc came from an up to 9/86 eta. I am assumg the coding should be fine right? THe gas tank should be the same size and... Right? If I swap my coding plug with the regular E one my rpm gauge will be off.

Third and this is the big issue. A while ago I swapped out my cluster for one with a working odo. Now when I plug in the obc it doesnt work. So I took my old cluster with only gas and temp guage and plugged it in and it seemed to work. The temp wasnt accutare but was off like 20 degrees. The lights didnt work either, any of them. I had this same issue with my 6 button. Any ideas?

Please the help would be greatly appreciated.

[motorsports_3]

So I couldnt let this go and kept messing with it. I think I got most of it done.

I ended up swapping the gauges from the new VDO cluster into my old Motometer cluster, and it seems to work.

I then changed the bulb in back and the rear lgiths up. I guess I need new rear led lights or whatever they are.

So I am pretty sure I dont have to swap out the blue harness.

Any ideas about the coding plugs?

TIA

[zav3n]

honestly i looked into doing this when i got my car and its really not worth it just get the cover and put a oil pressure/whatever gauge in its place.

[itsbrokeagain]

Im going to dump mine and get a 316 HVAC. Will come in handly later when I get a screen to go in the car.