my 81,240 d ,new to me.i know it has dash lights,but see no lights at dials or slider for hvaac controls.are there any ?its all dark at night

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95 e320,87 sdl,79 300sd

There is a multitude of bulbs on the manual climate panel.

Each knob has one in the center of the shaft.
There are two or three in the plastic panel that illuminate the words and the sliders.

And you have the fiber optic spider behind the panel that illuminates the rocker switches.

I suspect you have either all your bulbs burnt out or a broken wire. These sockets are all on a daisy chain like Christmas lights. The bulbs are in parallel, but if you have a break at the beginning of the chain they will all be dark.

Be careful taking the panel apart, chances are the plastic is extra crispy and will crumble.

The knobs and sliders pull off. There are 3 big nuts behind the knobs. Be very careful or you will cause the plastic "cups" the knobs sit in to crumble. Then the face of the panel pulls off and you should see the bulb string.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Should look like this:

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'82 300TD
'84 300D OM617
Auto to 4spd Manual Swap 716.210
'85 300SD 2.88 Diff (Direct Swap)
W140 HD Rear Springs w/ bilstein shocks (SLS Delete)
'83 300SD Big Brake Booster Swap
Late model 240D Manual HVAC Swap
W124 Outside Temp Gauge
Aftermarket Keyless Entry

'84 300D RIP

I think this is a dash dimmer switch issue as I have no dash or console lights.i think dimmer switch controls all dash and console lights

That is probably THEE most common issues on these cars. The rheostat being dead.
Here's a whole how-to on how to fix it:

PeachPartsWiki: Dash Light Rheostat Rebuild

Or alternatively you can solder it all together, bypassing the switch completely. Trust me, you don't want to dim the lights in a W123 anyway, they are barely visible on the brightest setting to begin with, making the rheostat about as useless as the rear fog light switch setting on a US-spec W123....

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"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)