89 240DL wagon- When I turn on my headlights, the little bulb out light on the dash comes on. I've checked the bulbs, everything seems ok, usually just goes off after a minute or so. noticed today it stayed on until I put the turn signals on- went off. ? any ideas? dave

 

Are all the bulbs matching brands?
Maybe the sensor is bad.

 

The bulbs would be an easy enough thing to check, where it the sensor you speak of? I'll get right on it once it stops snowing... Dave

 

The sensor is a red or black cylinder right under the instruments. Sometimes when they go bad the light on the dash starts coming on. Or the brake lights quit working.
It is also important on a 240 to make sure that all the bulbs match (all brass based or aluminum) and that the taillight connections are clean.

 

Yes the sensor is un under the dash like right under the speedo cluster.
It is usually a red sensor.

 

Thanks for the input. I did see the Red sensor while doing the blower motor a few months ago. New, I bet they are a good chunk of chance, wicked cheap at a junkyard. any way to testone of these? Dave

 

Open it up and inspect the solder joints really good.

 

I have an 86 240 DL with the same warning light problem, including inoperable taillights. The volvo dealer provided great advice and a "bulb failure warning sensor" wiring diagram. He said there is a weak diode in the sensor and they used to change them with a stronger one from Radio Shack. How to test I don't know. I temporarily fixed the brake light problem by installing a jumper between power in (terminal # 54S with blue red wire) and power out to brake lights (terminals 54L and 54R with both being yellow wires). Now I have brake lights and a warning light. Other advice included simply cutting the sensor out and direct connecting all the wires. A new sensor was $129.00 Canadian dollars.
Rene