I had some trouble with dash instrument lights so I replaced the bulbs and the potentiometer. All of the lights work, but the lights that illuminate the speedometer, clock gauges remain dim.

Any thoughts

JCD

I have the same problem on my 82 300D turbo. I went ahead and jumpered across the rheostat and all other lights (climate, switches) are nice and bright but the insrument cluster is still very dim. I'm goig to go ahead and change the bulbs to brighter ones. The schematic for the lights seem straightforward enough and there doesn't seem to be anything between the rheo and the bulbs so I figure it must be the bulbs.

I read where changing to brighter bulbs there is the possibility for melting some of the plastic. I was going to try that until I read one of the other threads on the topic.

JCD

When I replaced my old cracked dash with a "new" one, I switched out the bulbs for new ones of the same wattage. The plastic sockets had a fair amount of "melt" just from the original bulbs, so I was hesitant to go with higher wattage. I was amazed at the amount of crud (film from volatile compounds in vinyl and foam, misc. soot) that was on the old bulbs. The new OEM bulbs were much brighter, same rating. DC filaments maybe just get old in DC systems?

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I just got a 1982 240D, and it only had 1 very
dim bulb illuminating the cluster. When I
removed the cluster to replace the bulbs, I
noticed that a previous owner had put a higher
power bulb in, and it started to discolor and
melt one of the housings.

I would not recommend putting higher power bulbs
in. Instead, remove the instruments (with care)
and take a clean cotton diaper (or other clean
cotton cloth) and wipe the inside of the plastic
off. It does not make a tremendous difference
but you will at least know it's as bright as it
gets. Before you button it back up, if you
have any compressed air, (photography hobbyists?)
blow out the excess crud fragments. Do this in
bright light so you can see everything that might
be still floating around in there.

Jeff

__________________
- Jeff

1957 W121 190 (history)
1966 W108 250S
1967 W108 250S (parts)
1982 W123 240D (history)
1989 W124 260E

Don't go with higher wattage dash bulbs, stick with the Osram 3W bulbs. Just replace every bulb in the cluster and it will be a vast improvement. While you have the cluster out you can disassemble it and really clean the backs of all the gauges. You'd be surprised to see the backs are actually while, not dingy yellow .

If you are ambitious, you could even carefully repaint the backs of the gauges bright white to increase the light output to the gauge faces.

As your cars get older, you'll start using some of the "Vintage" tricks .

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.