Greetings from sunny southern CA. My brake light failure light has come on in my 1990 240 wagon. The pedal is good, the fluid level is good, and I find no leaks. The brakes are all fairly new, but the fluid is old. I've searched earlier threads but didn't see any that had this same condition. Any suggestions would be appreciated. Thanks.

Sorry, just couldn't help myself from the word play.

Neither of the two responses in the 700/900 FAQs apply to a 240. Not sure they even apply to a 780, either, as they describe the function of the brake failure warning switch in a 140, where the shuttle moved by a pressure differential locks in place to be reset by backing out the switch.

Maybe the 780 guy's experience led him to believe it worked that way because removing the switch did fix his light. That can happen with the 240 as well, but not because the switch locks the condition, but because the chamber where the switch is gets drowned in old, contaminated brake fluid which has leaked past the O-rings sealing the hydraulics from the electrics.

Here's a thread containing most of the alternative, er, correct facts.

https://www.brickboard.com/RWD/index.htm?id=1327815&show_all=1
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Art Benstein near Baltimore

Don't worry about avoiding temptation... as you grow older, it will avoid you. - Winston Churchill

Have you read the 700/900 FAQ?

I realize that your car is a 240 but many items work the same.

Go to - Brakes - then go to - Brake light on after bleeding.

This may have tripped your light - there are instructions to reset it.

It is possible that one of your dual circuits is not working, or you tripped the light somehow. I can understand that loss of one circuit may not lead to a bad pedal. just longer braking distance.

One of the reasons that your 29 year old car is still driving around is that someone or several owners has followed Volvo's maintenance schedule - you should do so also - like changing brake fluid on schedule.