So, I’ve noticed the “Brake Failure” light on the instrument panel doesn’t illuminate when turning the car on. I’ve checked/inspected the bulb and it seems to be alright. Is this one of those instances where I should Just replace the bulb with a good one and see if it works? Or isn’t it supposed to illuminate with the rest of the bulbs when turning the car on? Could it be a sensor or relay? I’d just like another opinion before removing that cluster... Again! BTW, the warning light didn’t turn on when I burst a brake hose, so I’m just a little curious. Thanks!

So, as it turns out, just a burnt out bulb. I tested a bulb I pulled from a previous car, with an ohm-meter and it didn’t show resistance. Put the bulb in, turned the key on, and presto! Only reason I wondered, is the light was never on the whole time I had the car. Didn’t know if the lights powered on differently year to year. But now I know. Thanks again, everybody!

Ironically, I believe you've started with the commonly preferred "fix" and un-fixed it, e.g.:

http://www.240turbo.com/volvo240mods.html#bulbfailsens1
#1 Recomendation: My best advice for those who are simply tired of seeing the bulb failure light come on when a bulb hasn't really failed is as follows.
Step 1: Reach under the dash and find the offending bulb in the back of the instrument cluster.
Step 2: Twist and remove.
Step 3: Take it outside and throw it as far as you can.

HI,

Glad you got it fixed!

Interesting that you put in a bulb that "didn't show resistance" and the bulb worked? That twisted up an eyebrow on my face?

Maybe you needed to try a lower scale that is more precise on the meter.

Maybe you used the continuity portion and it has a beeping sound part.

Sometimes the beepers won't work but you will have some resistance that means continuity anyway but higher than a ONE! If you get a "1" all the time you needed to change scales? Auto range can flop a decimal point movement on you too. Values change dramatically.

So, you have to be careful about selecting or using a continuity meter division next to a diode checker combination. Both look for very low resistances or more like a short circuit and then decides to show you a similar bias reading that is related to checking a transistors HFE which are diodes.

Confusing as heck huh! Tell me about it!
Electronics will be my achilles heel.

I have a meter with a little speaker and diode symbols together in one pie section division. It's on some dedicated automotive meters but it doesn't have a transistor plug or HFE section.
This makes sense for knuckle busting wrench pullers that have no use for them but it will still have a diode checker?
Again sort of confusing.

Anyway just my rambling under my eyebrows of curiosity.

Phil

Glad it was an easy fix.

"I’ve checked/inspected the bulb and it seems to be alright."

"Is this one of those instances where I should Just replace the bulb with a good one and see if it works?"

I'm having a hard time reconciling these two statements. If you've checked/inspected the bulb and it's ok, why would you need to replace it with a known good one to test further?

It should illuminate with ignition on/engine off -- and then go out when you start the car if all is well with the hydraulics of the brakes. The way you inspect the bulb to see if it's actually alright is -- 1) pull it and put power/ground to it to see if it illuminates; or 2) replace it with a known good bulb and see if it illuminates. If you haven't done one of those two things, then you haven't "....checked/inspected the bulb...." to determine if the bulb is faulty or if it's some other problem.

"""Is this one of those instances where I should Just replace the bulb with a good one and see if it works? """

Homer Simpson sez
The hoofbeats...odds are they are not Zebras

Bulb --- 2018-1990= START HERE

Why Do I own an Old Volvo 240....'cuz stuff is pretty much basic

Yrs Truly
Mr IronIC775

PS
if you are nimble or have small children at your command.
You can reach up there and twist out that bulb holder

Mr. ObnoXious

Yeah, I don’t know about all that. The engineers didn’t really make it easy to access that area. Last time I tried “reaching up in there,” I tore my hand up pretty good and tweaked my back trying to wedge my head, shoulders and arms up in there. Not that I don’t enjoy the pain that an old car’s dash area full of hard plastic, random sharp metal objects and wires brings, but you know.. If I was to fiddle w/that again, I’d just take the cluster out and work with it on a table.

You're absolutely right. The engineers didn't make it so easy to reach up behind the cluster from underneath. Not so easy as it was in CB's old 80's cars. And they knew it, between Volvo adding the SRS and VDO supplying a new cluster design every year to keep up. They had VDO fashion a Rube Goldberg reset cable for the Service Reminder mileage counter. In yours, you can put the Service Engine light out by poking a recess in the cluster's front panel.

By now you've got removing the cluster down in memory, if you've examined the bulb at all. I don't believe those bulbs are the horse explanation of hoofbeats, because they get such little use, a dud warning lamp is more of a zebra, but you have to rule it out. Even testing the bulb isn't definitive, as an aged bulb that is rarely used might just have its filament separated by vibration stress, so by the time you have it in your hand, the filament could be making contact, and test "good."

If the brake failure lamp is the only one not lighting in lamp test mode (key on engine stalled) chances are pretty good either the lamp is out or its lamp test diode and printed circuitry has a cracked solder joint. That's where the problem will be if the new or swapped lamp doesn't fix it.

I used to be able to squint at those bulbs to know if they were OK, snicking them with a fingernail to see if the filament was intact. Junkyard experience told me the cluster warning lamps were 95% OK and the others used for illuminating the console, etc. were 80% duds. Numbers certified by audit of course. :)

So, put another bulb in, or more likely swap it with one that you know works, hook up the cables to the cluster and check the lamp test feature before you put the screws back in. If the problem persists, you'll want to disassemble the cluster's circuit board from its housing to look at the traces.
--
Art Benstein near Baltimore

“The only true wisdom is in knowing you know nothing.” -Socrates