Hi everyone. I have a 1980 244GL which I now have running like a dream. Problem is on starting the car this morning the bulb failure warning light on the instrument cluster is on and stays on but it appears all my lights are working just fine. Is this a common problem and if so what would the likely candidate be to remedy? I have read that the control relay is prone to failure on some later models and can be repaired with some careful soldering? Does anyone know what this looks like and where it lives so I can pull it out and inspect? I knew something had to give once I finally had her running like new....... no rest for a Volvo owner!

thanks guys for responding, very helpful. Funny thing is I got in the car to drive home from work and the problem was gone, strange but a good result. Perhaps a sign of an impending failure of the sensor but for now i'll live with it untill it comes back on.....

My guess is slight oxidation on the Tail light circuit boards.
Now that you are 'bored' with the car running so well : ). Grab a Pencil eraser, pull out each Light socket in the Tailight assembly and clean the connection surfaces of the Cicuit board. Get the copper shiny again. My guess is that some oxidation is causing a little more current draw on one side of the car vs the other giving you the Idiot light.

Also..when putting the lower corner sockets back in (Brake lights) don't fully turn them. The contact points of the socket drifts off the radius of the Assembly causing a bad connection to the circuit board.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

You will find info on the control relay in the 700/900 FAQS section.On a 1980 I believe it is located above your left knee tucked up under the bottom edge of the dash it is cylindrical about 2" in diameter and aprox. 3" long and will have a multi wire plug in. Miss matched bulbs can cause imbalance in the system or a sketchy ground can also cause the failure light to come on.Good luck

I don't know myself. IPD has a description of troubleshooting the bulb integrity sensor :
http://ipdusa.com/Volvo-200/Lighting-&-Lenses/Bulb-Integrity-Sensor/p-69-263-375/