Hi there! I'm fixing up my 85 240GL, and I've run into a few problems.
One of them is that my dashboard lights won't turn on. The instruments work fine, but nothing, with the exception of the parking brake light, the turn signal indicators, and the bulb failure lights, will light up.
Worthy of note is that my dimmer switch will not turn one way or the other, even with pliers. The fuses are fine, with the exception of number 5.

I also have brake light problems, which I've posted about in another thread. My brother thinks that the two are related, but I'm not sure, as evident by the dimmer switch.

From reading up on the forum, it is most likely the dimmer switch, but it might just be the bulbs. I'm headed to the junkyard later today, and I just want to condense my trips into one.

Any thoughts if it could be something else?

 

unplug the dimmer and use a bit of wire to connect pins 58b (green wire) and 58a (brown wires) directly, then turn the light switch to parking lights or on, and your dashboard lights should come on. if they do, its just a bad dimmer.

that greeen wire comes from fuse 16, which should be powered when the headlight swithc is in park or on (via a white wire to pin 58 of the headlight switch). the headlight switch in turn gets its power from a green-red wire on pin 30 that comes from the far right fuse panel spadelug next to fuse 7 (this does NOT go 'through' fuse 7, instead its connected to the red wire that goes to the rear/right lug next to fuse 6, which comes from the 'positive terminal' under the hood lots of red wires are connected.

 

What kind of wire would I use to connect them? Anything laying around?

 

yeah, even a bent paperclip

 

Fixed!

 

I am not familiar with the what the pins are. I found two brown wires connected to the dimmer and two - one red and one white connected to the dimmer. Where do I locate the green wire. I also discovered that the bulb relay sensor wires are all cut and connected in odd places. The plug is still there but no relay. I can grab one out of a salvage yard car. However, where do I start getting the dashboard to light up again?

See schematic for rheostat...

 

ugh, re the bulb out, sounds like someone butchered the wiring. if I had a bad bulbout, I' cut it open, remove its contents, and turn its plug into a jumper block that bypassed it.


240 wiring colors are NOT that reliable, they changed rather often. but, I might have crisscrossed green (GN) and grey (GR in Volvo-land).

 

A picture of wires that are cut

 

the bulb out detector has your low beams, front parking lights, rear parking lights, and brake lights going trhough it. if all those are working correctly, then the splicing is probably doing its job. if ever one of those lights gets flakey on you, you'll have another place to look for problems (in addition to the normal switches, sockets, connectors).

the dashboard illumination doesn't go through the bulb-out, so thats a whole different problem