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'88 240 Cluster Lights and Gear Selector Light Not Working

J

Johnnya101

Member
Joined
Jul 12, 2017
Hi again guys,

Got an issue with my 240. None of the lights on the cluster of my 240 appear to be working (If they are, very very dim), and also the selector light for the shifter does not light up either (There IS a shifter light right?). In addition, the drivers seat heater switch does not light up when on. Could all this stuff be related?

I believe this is not a fuse issue since the gauges and seatbelt light and stuff like that all work?

What could the issue be?

Thanks!
 
Pop open your fusebox and check fuse 16 to make sure it's intact. Be aware sometimes they can crack and appear to be OK at a glance while actually blown. Spin it in the socket - this helps knock loose any corrosion.

Pull the trim panel to the left of the instruments (you'll need to remove the knobs first) and look at the back of the dimmer switch. According to my diagram you should see 2 wires - gray and brown. Connect them together and give them a quick wrap of tape to make sure they don't short against anything (if you do, you'll need to replace the fuse). Does that make your lights work?
 
Thanks! It's dark right now and don't really want to do this now, so I'll wait until the morning. So connect the brown and gray wires together, make sure they are not touching anything else? If they are touching the fuse won't blow or anything? Just don't have any spares so don't want to break them right now lol.
 
You're bypassing the rheostat which controls the light brightness. if that makes the lights come on it means the rheostat is bad.

Having them bridged together just means you'll have maximum brightness on the lights. The issue is that if the wire ends touch other wiring or metal inside the dash, they can cause undesired operation, or short to ground and blow the fuse.

Definitely buy a pack of spare fuses to have on hand just in case. Can be worth going through and double-checking to make sure none of the fuses are larger than is specified, too - some people replace fuses with the wrong size, which can mask electrical problems but cause issues like melty taillight sockets.
 
I see two brown connected wires and some white and a black one going to a switch...?

The brown ones are buried in there.

Also the dash light pot is broken I think it turns freely...
 
Johnnya101 said:
I see two brown connected wires and some white and a black one going to a switch...?

The brown ones are buried in there.

Also the dash light pot is broken I think it turns freely...
Click to expand...

Are the two brown wires the only one connected to the dash pot?

if so, jump them - if your lights come on, that confirms the source of your problem is the pot. ;)
 
Did it happen suddenly? You may just need to replace the bulbs. I bought a 93 last year and had to replace the rear ashtray, all center dash, shifter, some warning lights and never knew they came with seatbelt buckle lights.

I suggest grabbing a test light, They are cheap and have been pretty helpful owning a 240.
 
Yes, I think the brown ones do go to the pot! So just unplug them or whatever and touch them and everything should light up?

I bought the car with the lights not working. Luckily it sounds like a simple issue.
 
Johnnya101 said:
Yes, I think the brown ones do go to the pot! So just unplug them or whatever and touch them and everything should light up?

I bought the car with the lights not working. Luckily it sounds like a simple issue.
Click to expand...

Yup, although they're hard to see in daylight - also make sure your headlights are on, since at least on my '87 they only turn on with the headlights.

If this doesn't identify the problem you'll need to get a multimeter and follow the connections back towards the battery until you find voltage. But we'll cross that if we come to it.
 
Had to unscrew the cluster and take it out a little bit to unplug those wires but I managed to unplug them.

There are four total wires. Two browns which are melted together and go to the same pin, and two wires that are melted together that go to another pin. The two wires are red and white (solid red stripe), and gray...

Now what? Am I touching them all together?

How would I know if there's broken bulbs? I find that unlikely for none to work and the pot to be broken but...
 
Also, is it safe to leave them unplugged with electrical tape on them so they don't short until I get a new pot (if that's the issue)?
 
1. Yes - since there's still only two pins on the back of the pot, shorting the two wire groups together should be fine. They should be designed to be connected - you're just bypassing the pot which normally controls that connection. (Are they actually melted? That's odd. Snap a photo?). I would only worry if you had multiple pins at the back of the pot - then we'd want to determine what the extra ones did before shorting voltage to them.

2. To check for blown bulbs, you can either check for voltage at the bulb socket with the lights and key ON (voltage but no light = blown bulb), or pull and visually inspect the bulb (visible, intact filament = bulb probably OK).

3. Yes - or you could even crimp them together or install a 2-pin switch in that spot. Just be aware that a connection made with just friction and electrical tape could become disconnected unexpectedly if you leave it like that for a long time. Then you won't have any lights. :nod:
 
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Ooohhhh the switch idea sounds great!

Yeah I just duck taped them for right now, I'll go out and test now. There are only the two pins. The wires aren't melted, just side by side connected...
 
Nope, nothing happens. Switched he headlight switch to all positions, nothing. I did not hear any pops either for a fuse being popped either so that's good. :)

Soooo check the bulbs next?
 
Johnnya101 said:
Nope, nothing happens. Switched he headlight switch to all positions, nothing. I did not hear any pops either for a fuse being popped either so that's good. :)

Soooo check the bulbs next?
Click to expand...

Yeah, and check for voltage with a voltmeter.

(You did have the key on while testing, right?)
 
Yes of course! Lol. Had it in I. Don't think turning it on fully would have a difference?

How should I access the bulbs? I've read I could either take out the dash or stick my hand under the wheel section?
 
For the instrument cluster lights, I'd unscrew the cluster, pull it forwards and reach around to the back. The lighting bulbs are along the top, one each about 1/4 of the way in towards the center. Twist to remove.

https://cdn.discordapp.com/attachments/196496627660357632/345016513767669770/unknown.png

This is an old cluster, yours will look different but the bulbs will be in a similar spot.

If you decide to unplug the cluster to get access, do NOT plug the red and white tachometer wire onto anything except a tach!!! If you don't have a tach, just leave it loose like it was from the factory. It will fry your speedometer if you hook it up wrong. :nod:

I haven't had to replace any of my other bulbs yet, so unfortunately I can't suggest anything with those.
 
I've got the clock, no tach so I'll leave that alone :)

Other bulbs as in the gear selector one? It's just the two in the cluster I thought.
 
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