89 240, Headlights are fine, brake lights are fine- why does that damn dash come on when I turn on the headlights or hit the brakes? Dave

 

Sounds like a mismatch or faulty light bulb. The bulb failure warning sensor (BFWS) is detecting unequal current left/right and it lights up the bulb failure light. I would clean up the contacts, grounds, and replace bulbs with matched pairs if necessary. It could be a bad BFWS, the fat red cylindrical relay to the lower left of the cluster.

 

Blue- that sounds easy enough, I'll look at those bulbs. D

 

I had the same problem..found mismatched brake light bulbs one was a german bulb the other chinese..different wattage ratings caused differential to develope in circuit illuminating bulb failure light. installed new 1156 bulbs and life was good!

 

Maybe I'm the idiot! Dave

 

Just yank the warning lamp bulb out. It's a pretty useless warning if you ask me....it false alarms about 20x more than it detects a positive.

Regards, Andrew.

 

Those bulb failure relays are aggressively useless, and mine had a habit of blowing fuses until it melted its ground wire and released a cloud of noxious smoke. Apparently Volvo does not put a fuse on its headlight circuit, and that circuit runs through the bulb failure relay. So instead of blowing a fuse when it shorted out it asploded. Instead of buying a new one I just touched wires together to find out which ones lit up which lights and spliced the right ones together. If any of you experience problems with your bulb failure relay I will provide this list of what wires do what with the warning that yours is probably different if you don't drive a '75 and touching random wires together like I did is dangerous and I can't recommend it.


1 Red & Blue . . Brake lights live (only when brake pedal is depressed)
2 Yellow . . . . Left brake light
3 Yellow . . . . Right brake light
4 Green. . . . . Headlights live
5 Blue . . . . . Left headlight
6 Blue . . . . . Right headlight
7 Gray . . . . . Left tail light live
8 Red. . . . . . Left tail light
9 Brown. . . . . Right tail light
10 White . . . . Right tail light live
11 Yellow & Blue Idiot light
12 Black . . . . Ground

 

Hey everyone, recently bought a '89 244DL, and have been having a blast driving it around. Aside from replacing the alternator and doing a full tune-up, it seems like everything is in good condition. My brake light seemed to burn out a couple of days ago, so I went in to replace it. It looks like the previous owner did some work on the rear lights, as there is some sort of paper-thin plastic circuit board with copper contacts. The light that went out appeared to have burned through the cheap plastic, and was no longer making good contact. My brother and I experimented trying to get it to make good contact again but ultimately failed. I ended up pulling the wires out of the plug, and hard wiring it to the brake light socket. Now the brake lights work perfectly, even though this one is slightly more dim(different bulb). So my question is am I risking something bad happening because of the different bulb types? Also, I am not using one of the connections that exists in the socket that holds the brake lights. I can't figure out what this extra connection does at all, but I want to be sure this doesn't cause me problems in the future. Any info would be appreciated.

Thanks for the help, and great forum!