Yellow service indicator??

[gurgli]

Hi,

I have a m10 316i 88'

When it is cold, the yellow indicator ligth (there are 3-4 green, 1 yellow and 1 red) will come on. When the engine heats up, the light turns off.

The yellow is the only light that is ever on.

Anyone know what this could be? I don't really know what triggers these lights, as I don't have the manual for this car.

Only thing I can pinpoint as beeing unusual with the engine is that it idles over 1000 rpm, even after its hot.

[Brianmoooore]

The yellow LED probably is a first sign that the batteries on the SI board are failing. The batteries are very sensitive to temperature.
If left unrepaired, then other symptoms will probably appear (problems with rev counter, temp gauge etc) and eventually the batteries will leak and corrode the SI board into scrap.
The 1000 RPM idle suggests possible problems with the blue ECU coolant temperature sensor, or possibly someones been "adjusting" the throttle stop screw, or even something silly like a tight throttle cable.

[Gortour]

Batteries can be replaced if you can get em out before they leak and totally scrap the board, as Brian says.
This is something I have done on at least 5 occasions on my cars and those of my friends and family.

The main thing is getting the batteries, which are basic AA size, but with terminals on the ends to solder in to the board, rather than the standard lump at one end and a flat on the other.

The batteries are available from decent electronics places (Farnell, RS, CPC, probably Maplin etc) and with a soldering iron to hand can be changed in less than an hour including removing and refitting the dash.

Where abouts in the country are you gurgli? If somewhere near me, I'm happy to help.

[gurgli]

Thanks Brian and gortuor,

I'll rip out the panel and replace the battery and order the blue sensor )

[Brianmoooore]

CPC do batteries that are only 2/3 the length of standard AA batteries, which are much easier to fit in the space available without shorting on nearby components.