The other day (while driving in daylight), the bulb failure light was on steady, but no running lights, head lights, turn signals, etc were on. The next time I drove the car, all was OK. Anyone know of a reason? (A reason for the indicator being on, not a reason for everything being OK.)

If none of the lights appear to be malfunctioning, and the bulb indicator on your dash comes on when you brake or signal only, I'm 99%
sure that it's just coming on because you've used an aftermarket bulb instead of the "superior" Volvo bulbs.

I did just that with a brake light bulb, and every time I brake the little light goes on.......good thing is , when a different light burns out, the indicator still comes on all the time like it should. 2 days ago I stepped out of my friend 84 Dodge caravan of which a signal light had just burnt out, stepped into my 760 and promptly cooked a headlight....... too much beer the night before ??!!?? wierd.

chris, the bulb out indicator has come on for many folks here before, but i'm not sure about it being steady. my own personal experience had it coming on when stepping on the brake, or flashing in time with the turn signal. what i did to fix this problem was go to the rear, and disconnect the wiring harness for the taillights, and then cleaned off the contacts for both sides. then i put some vaseline (or use dielectric grease... as long as it does NOT conduct!) on the contacts, and plug the harnesses back in. the bulb out indicator no longer came on.

sometimes, mismatched bulbs on both sides will cause it too, but i suggest you check/clean the contacts first before running out like i did replacing every single bulb. i now have an extra bag of type 1006 bulbs as a result. :)

edit: yikes, i misread your post. i thought you said that none of your running lights were OFF, as in they were all okay. if all your lights were off, then go with what the previous poster said about the relay. :) sorry about that!
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Kenric Tam
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'

Chris;

It sure sounds like an intermittent failure of the bulb failure sensor...IT controls the bulb failure light, and if no lights were ON at the time, but it was turning on the failure indicator...that seems pretty clear. The intermittent condition will probably occur again, and possibly get worse if you let it go.

Bulb failure sensors are not cheap...but if you're confident working with electronics and soldering, repair is possible...I suggest removing the sensor, carefully extract the guts from the case, and inspect the solder joints on the PC board with a lupe...look for questionable/compromised solder joints (sometimes a circle of oxidation around component lead is visible...this is a pretty good hint). Resolder, reassemble, reinstall.

Good Luck

I've resoldered some of the other relays' circuit boards with pretty clean results. Like you said, with a good lupe and my new reading glasses that I picked up at the Dollar Store for (you guessed it) $1.00, I should be OK. Where is that relay located?

By the way, I got an excellent high rez scan of the circuit board on a Radio Suppression Relay before it was soldered. I was going to post it to the BB so people could see what to look for when trouble shooting them, but I couldn't get the file size within Jarrods limit - only about 65K or something like that.

Chris;

I'm not positive, but is'nt it located on the relay panel with its comrades?

OK on soldering your RIS relay...as far as the "before picture" goes...you mean like this one?

http://www.intelab.com/swem/volvo_relay_pn1323592_failure_issue.htm

Cheers