I have an 89 740 GL, I was recently hit an run resulting in the right hand low beam headlight being busted, after fixing it today the "Missing Light" idiot light was still on in the dash, I checked all blinkers, reverse lights, headlights, running lights and brake lights and all are in fine working condition.

The only thing I can think of is I replaced it with a slightly better bulb than the rest of the bulbs in the car (an Xtravision Sylvania Halogen versus the standard Sylvania Halogen) could it possibly be measuring a load difference due to a different resistivity of the filament and confusing that with a burnt bulb?

Also the "Missing Light" idiot light goes off when I turn high beams on.


Any help would be great.

 

your low beam is taking a different resistance.
Replace both bulbs.

 

The bulb out module on these cars is ridiculously sensitive. Instead of having to replace both bulbs, just yank the stupid warning light. Seriously, you will know if you have a bulb out.

Regards, Andrew.

 

this is broken in my 85' 240, and in multiple other 240's i know of. www.ipdusa.com has new ones for pretty cheap

 

thanks, I figured it was just the resistivity since it was working fine ahead of time. I'm surprised its that sensitive.