e30 Service indiator not working properly

[selespeed]

hi;

I have a e30 with a 36m42 engine inside. the service indicator has not been changing for months since stuck at orange level. it ought to change to RED showing the final warning. the orange light is stuck at orange since at least 2 months ago.

the last reset was done in August 2014. and 20,000 km later it doesn't show warning (red), just stay at orange light for too long!

a few days ago, it changed to RED but stayed on for only one hour. the next restart of engine did not show RED and subsequently it remained in orange. I suspect something is wrong. but i dont know what. anyone has this problem? is wiring the culprit? how to solve this?

thanks.

teo

[DesktopDave]

Probably the SI board batteries. Here's some recent info about these batteries. Infamous problem with all the 80s BMWs.

[selespeed]

Probably the SI board batteries. Here's some recent info about these batteries. Infamous problem with all the 80s BMWs.

Thanks but what is SI board?

[selespeed]

Probably the SI board batteries. Here's some recent info about these batteries. Infamous problem with all the 80s BMWs.

ok, the instrument cluster. but all other gauges are working - fuel, revv etc! the orange warning light stays on fine but it just could not switch to the RED light. when it does, it stays on for like half hour and then back to orange. i don't think this is due to battery

[DesktopDave]

Yep, the gauge cluster has two batteries. They're not the same as the car's battery, LOL.

These two little NiCD or Lithium batteries sit on a removable electrical part called the Service Interval board. You can remove the SI board from the gauge cluster once you've pulled the rear cover and main circuit board off the back of the gauges.

[selespeed]

Yep, the gauge cluster has two batteries. They're not the same as the car's battery, LOL.

These two little NiCD or Lithium batteries sit on a removable electrical part called the Service Interval board. You can remove the SI board from the gauge cluster once you've pulled the rear cover and main circuit board off the back of the gauges.

thanks Dave.

but what are the functions of the two batteries?

i tried to do the service reset yesterday but it would not turn off the orange light. then i did inspection reset and that removed the orange light and it is now reset. so when i turn the ignition key all the 5 green lights are turned on and when i start the engine all lights go off!

so all the service lights work except the one RED which doesn't want to stay on permanently when it is due. why?