Brightening Dash Light

[W123dMercMania]

Since my 1982 300d instrument cluster lights are extremely dim, I decided to remove the speedo unit to clean and re-install the lamps with the new ones in the hope that I will be able to see the speedo and odo digits clearly at night time. All cleaning done and lamps replaced but no significant improvement. Rheostat works fine.

Is there any other type/make of lamps available to brighten the dash? Any suggestions?

[ayalar007]

I've always thought the same thing. I once read in one of these forums that increasing the wattage of the bulb is a NO NO, becasue it melts the plastics, but they did recommended paiting the inside a chrome color to better reflect the light, but with all the new technology out there in lighting, I too was wondering if there is a better bulb for the dash. Sometimes at night I cant see my odometer.
W123dMercMania, let me know if you find out anything!

[rwthomas1]

Solder a jumper wire over the rheostat to take it out of the loop. Can't imagine why anyone would want DIMMER dash lights in a MB anyway. Paint inside the plastic housings around the "prism" with bright white Testors model/hobby paint and small hobby brush available at hobby shops. The white helps reflect the light. While you are at it pick up some fluoresent orange Testors paint as well and paint the instrument needles. Install new bulbs but DO NOT INCREASE THE WATTAGE!! You will melt the housing. Some have successfully installed LED's so do a search on that. The trip odo can be cleaned with rubbing alcohol/Q-tips and some of the numbers on the mileage odo as well. RT

[tangofox007]

www.**************.com sells a xenon bulb "upgrade" kit which is intended to address the problem.

[ayalar007]

Originally Posted by tangofox007

www.**************.com sells a xenon bulb "upgrade" kit which is intended to address the problem.

But I think this Xenon bulb is for the dome light not the dash. Am I correct??

[oldnavy]

Originally Posted by tangofox007

www.**************.com sells a xenon bulb "upgrade" kit which is intended to address the problem.

Those are snake oil, they are just regular bulbs painted blue to give off a whitter light. Trouble is it cut's down on actual light output, when bulb is painted. One of my speciality fields is optic's, so I know what I'm saying.

[Tirebiter]

I put shiny Mylar on the back of my light guides and jumped the dimmer switch. It is acceptable now where it was barely tolerable before.

I replaced my bulbs with the correct wattage, and that helped a little... I have just learned to live with it however. I mostly drive my Subaru at night anyways, and I can see that guage cluster at night...

[rg2098]

Personally I like the dim lights, my eyes don't have to adjust as much, but its bright enough to see the guages i need to see; kinda like the Saab night panal effect (yes Roy I said Saab).

[hockeynut]

I'm gald this thread was started - I have a somewhat related issue. Tonight my dash lights stopped working. The dash lights and the switch/climate control lights just stopped working. Everything else on the circuit works...I was hoping it was something as simple as a fuse. I see there is a rheostat in line - could that have gone bad I wouldn't mid jumpering around it if that is OK. The lights were definitley dim. Please tell me it could just be the rheostat and I can jumper around it. If it is, how hard is it to remove the dash and where is the rheostat
Thanks for your help

[tangofox007]

Originally Posted by ayalar007

But I think this Xenon bulb is for the dome light not the dash. Am I correct??

The bulbs are for the instrument cluster.

I have not tried this product. I am not recommending it. I happened to see the item when I was looking for a another part, so I passed along that information. I have no idea whether the product is "snake oil" or the real deal. My dash lights are plenty bright with the original bulbs. I usually have the rheostat turned down about half way.

[tangofox007]

Originally Posted by hockeynut

Please tell me it could just be the rheostat and I can jumper around it. If it is, how hard is it to remove the dash and where is the rheostat
Thanks for your help

The bad news is that it is real hard to remove the dash.

The good news is that you don't have to. Just push the instrument cluster out from behind. The rheostat is on the back, just behind the rheostat knob. (Those Mercedes engineers think of everything!!) The rheostat is held in by only one screw. You don't even have to completely remove the instrument cluster, just pull out enough to get to the rheostat. The rheostat connects to two small prongs at the top corners. If you jump the prongs and the lights work, you will know that the rheostat is the culprit. If you don't need the rheostat, make the jump permanent. (I would solder a jumper onto the back of the rheostat, then reinstall.)

[lrg]

It's snake oil. I fell for it and it was a waste of money. The light was bluer but actually worse at lighting the panel. I then tried a higher wattage light. Bad idea, it did melt the clear plastic "light transmitter". Next I tried the bright white LEDs and those were no improvement because the light is very directional and it didn't reflect well onto the instruments. I finally bought a new cluster housing on EBay (to replace mine with the partially melted light transmitters), repainted the white reflector and went with new OEM bulbs. It is the best fix, no question about it. By the way, if your bulbs are old replace them. They get dirty and dim over time. It's not a huge improvemnet but noticable.

[hockeynut]

Originally Posted by tangofox007

The bad news is that it is real hard to remove the dash.

The good news is that you don't have to. Just push the instrument cluster out from behind. The rheostat is on the back, just behind the rheostat knob. (Those Mercedes engineers think of everything!!) The rheostat is held in by only one screw. You don't even have to completely remove the instrument cluster, just pull out enough to get to the rheostat. The rheostat connects to two small prongs at the top corners. If you jump the prongs and the lights work, you will know that the rheostat is the culprit. If you don't need the rheostat, make the jump permanent. (I would solder a jumper onto the back of the rheostat, then reinstall.)

Thanks - I will remember this if I need it down the road. After my earlier post I decided to do what I should have done to begin with - a search I found a thread where the guy was talking about resetting his trip meter and the lights no longer worked. That's exactly what happened to me, I fueled up, reset the trip odo, started, turned on the lights and oops. I am rather embarrased to sat I didn't even know the dimmer switch was one in the same with the trip odo. I just went out, played around with the switch and presto, the dash lights worked again. I suppose my rheostat may be going out or corroded, but for now all is OK with the world I love this forum

[tangofox007]

I recently replaced my rheostat. Bought a new one before taking the old one out. I found that a small piece of plastic had broken off inside the rheostat, fallen into the resistor coil, then was ground into small pieces as the contact moved across the coil, causing the dash lights to be intermittent. All the old rheostat really needed was a good cleaning.