First off, I have a 1992 Volvo 240 Wagon. We noticed the evening we bought the car that it had no dash lights, and various switches didn't light up. (ex. Hazard Switch, A/C Switch) Shouldn't those light up to be visible at night? I'v checked fuses and everything seems to be fine fuse wise. We tested the rheostat, and it seems to function. Also, would anyone have any idea on how to replace the bulbs for the dash lights? It seems as though you must take the steering wheel off just to get the instrument panel to come out all the way. From what we could see, there didn't appear to be any direct access to bulbs. Any advice on that would be appreciated.
One other question: When I press on the breaks, the light warning of bad bulbs comes on, however no break lights are bad. I've done some Googling on that, and some say a bad relay may be the cause of that. Any thoughts on that?
Any answers would be greatly appreciated.
Thank you,
Evan

 

The instrument cluster must be removed to gain access to the lights that illuminate it. It can be done without pulling the steering wheel. Just remove the trim pieces to the left & right of the instrument cluster to expose the 4 screws that hold the cluster in. Remove the screws and the cluster should slide straight out. The steering wheel must be straight in order for it to slide out. You then need to disconnect the wires - paying close attention to where each wire goes. The bulbs that illumniate the dash can then be removed from the back of the cluster.

When re-assembling it, don't find a home for the red/white wire if you don't have a tachometer. Many people connect it to the double spade with the yellow wire. If you do that, you will fry the chip for your speedometer.

As for the bulb indicator, check the brake light bulbs on both rear lights and make sure they are identical bulbs. Sometimes mis-matched bulbs will cause the bulb indicator light to illuminate. Check for corrosion when you check the bulbs. If the bulb indicator light still illuminates, then you may need to replace the cylindrical relay that is under the dash on the drivers side. They do fail and can cause all kinds of brake/tail light wierdness.

Good luck

 

Thanks for your reply. I'll get to checking these things most likely tomorrow, possibly late tonight. I'm busy today. I'll post back if I have any questions. Still one thing however, the ac/heat and all of the switches in that area, they don't illuminate. Shouldn't they?

 

all the switches are lit, but they are all on the same rheostat circuit as the instrument lights, so if those are out, its likely a common wiring point.

when you said you tested the dimmer rheostat, what exactly did you test?

 

When we tested the rheostat, we tested for continuity. It seemed to work fine. What could be a possible point where a fault would be?

 

when hooked up, and the car is turned on and the headlights are switched to parking lights or on, the green wire (pin 58B) at the rheostat should be +12V. with the rheostat on maximum, the brown wire (pin 58A) shoudl also be at or close to +12V, but it should go down as the rheostat **** is turned down.

the +12V comes from the battery ('red') through the positive terminal (still red) to the input rail that feeds fuses 6-7-8-9-10, and from that input rail is green-red to the light switch pin 30. light switch pin 58 provides the power via a white wire to the input side (left side) of fuses 15 and 16, and the output of fuse 16 (right side) is the green wire to the rheostat.

this same green wire also provides power for the ashtray and glovebox lights (these don't dim).

with a volt meter, you should be able to figure out why power isn't getting to the dashboard lights.


btw, if your 240 has old aluminum or tinned ceramic fuses, I *highly* recommend just tossing them ALL out and replacing them with new copper/brass ones, they last longer. you can find these on ebay quite cheaply as 'Mercedes W124 Fuses', its more than enough to replace every fuse and have plenty of spares. clean the brass fuse holder fingers while you're at it.... SOME FUSES ARE HOT EVEN WITH POWER OFF, SO EITHER BE CAREFUL NOT TO SHORT STUFF OR DISCONNECT THE BATTERY GROUND LEAD WHEN DOING THIS!!

 

You mentioned a green wire that also powers the glove box and ash tray. Those lights don't work as well. So it must have to do with that wire I'd assume.

 

oops, I made a minor mistake. its the SEAT BELT FASTEN light not the glovebox thats powered with the ashtray light... and per the location diagram, its the ones for the BACK SEAT, not the front.

the fasten seat belt and ashtray are on a white+red wire that comes off the +12V side of the rheostat where the green wire attaches, to be more concise.

I'd be looking at fuse 16 with a volt meter... find a good ground somewhere, probe both sides of that fuse with the headlights on....

ya know, it IS possible all these lights are dead... our 87 only has a few left working.

 

Thank you for your responses. I believe it will help. I am also going to study wiring diagrams in a Volvo Repairing manual I have. I can look at the advice and figure out some of the things being talked about on it.

 

the diagrams in the bentley book are unreadable. the volvo wiring diagram for a 1985 is here, http://www.k-jet.org/files/greenbook...985_PRELIM.pdf yours is probably close enough to the same as not to matter with respect to this. in fact, its identical to the 1986 diagram I'm looking at. find the page "Lighting instruments, and controls" about 56 pages in.

 

Your diagram you sent, Fantastic! I can understand it and I have no knowledge involving wiring at all!

 

After studying that diagram.. looks like anything depending on the rheostat are the things that aren't working.

 

so the lights ARE on the back ashtray and rear seatbelt lights?

 

Nope.. now that i check, no back seat belt lights or no ash tray lights...

 

ok, if the rear seat belt light is lit, then odds are the rheostat is seeing power on its input, so either the rheostat itself is bad, orthe brown wires to the various dimmable lights aren't connected, or all the lights are bad.

 

I just ran and checked... no back seat belt lights.. no ash tray lights... sorry for me being unsure... also found out i have no parking brakes -_-

 

ok, so we're back to checking fuse 16 with the volt meter.

black lead to ground somewhere, red lead to either side of F16, do you read 12V ? (with the engine key on II and the parking lights on...). if you do, check to see if there's +12V at the green wire to the rheostat.....

 

I think i shall get back to this tomorrow. Right now I can't park my car in the garage, so I really can't see anything I'm doing in the car when it comes to using the multimeter. I'll let you know my results sometime tomorrow if thats ok?

 

Hey, turns out it was every bulb! I got the bulbs for climate control and all that fixed, but I have a question pertaining to dash light bulbs. Would these bulbs work? Light Bulb 12V 3W w/ Base They have the same specifications listed in the owners manual, but the numbers on the sides are different. The ones i pulled from my car have w165. These ones read w865.

 

if they have the same base they shoudl work. are the filaments the same general shape? that might effect how the light is distributed (more important in reflector situations)