Ok, daughter was driving home last night and the instrument cluster lights went out. I had noticed that the lights were slightly dim or one bulb was not lighting correctly. So I removed the instrument cluster and swapped some of the other bulbs from the bottom row of the panel and that did not fix the problem...I suspect the rheostat is non functional. Does anyone have a good method for troubleshooting the rheostat?

 

If we're talking about a 240, I would wrap a wire around the two terminals of the rheostat to short it out. Pull the ***** off the rheostat and the light switch then pop off the plastic panel around the fog light switch. Or you could try spraying the rheostat with electrical cleaner.

 

I'm sorry yes it is a 240...ok so you are saying just eliminate the dimming function of the rheostat by shorting it out??... if the rheostat has failed this will allow full voltage to the lights I do believe....thanks

 

Right. I've rarely had occasion to use the dimming rheostat and the instrument lights are pretty dim anyway. Just shorting out the rheostat eliminates that possibility.

You can get another from a junk yard. There should be plenty depending on where you live.

 

bad news, I shorted the rheostat..no change. I then broke out the fluke meter lights on rheostat works fine but no instrument lights. I noticed that fuse#16 does not have voltage until you turn on the headlamps.once on then the rheostat has power to it as well and modulates the power.
I have a white wire red stripe that comes off the rheostat and disapears into the wire bundle pic1..I also have a white wire red stripe that comes out of the bundle behind the instrument cluster and goes???nowhere
pic2 On the back of the cluster assy there is nowhere for this connector to go?? pic3
since disassembly and reassemble now the right turn signal in the cluster doesnt work..I'm working backwards instead of forwards!!

 

I see your 240 is '86+ judging from the cluster pic. Using the diagrams of '86, the W-R wire from the rheostat goes to the ash tray and seat belt buckle lights. No dimming.

The headlight switch provides 12v to F16.

 

I have been trying to find a wiring diagram for the 92 240 any help?

 

Other than the official Volvo green books, the best is probably Volvo 240 Service Manual by Bentley Publishers. Take a look at IPDUSA and Amazon.

 

White-red is a direct feed from fuse #16 goes to the seat belt lights and ashtray, Brown from the rheostat goes to the gear position and instrument panel lights.

PM me your email address and I'll send you the 92 wire diagram.

 

Ok so I thought the turn signal bulb was the instrument cluster bulb
p/n W0133-1659993 both of the bulbs are blown! All I needed was to replace 2 light bulbs. The bulbs with the red base are the instrument back lighting they are OSRAM 12v 3 watt bulbs cant find them in your run of the mill part stores. The black bases are your turn signals parking brake bright light service engine etc. etc.

http://www.autoanything.com/Parts/Pa...iloName=lights
I guess I will have to wait until monday to get the bulbs as they are not readily available