All of the center console lights do not work on the manual CC area. The wheel for the a/c temperature works. The instrument cluster lights work and I can dim them with the rheostat ok. I checked the Lt panel & the Rt panel lights both work that are in the dimmer circuit. The only thing I did was remove the electrical connections and re-connect them replacing the heater control switches. All of the turn signals & brake lights, head lights all working ok. I replaced the intermittent wiper relay while the cluster was out, and it now works.

pull the knobs off and replace the grain bulbs behind them...

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Yes, well I have all the knobs off of the heater control switches there. I have replaced all the bulbs with new ones. The a/c wheel is the only one that is lighting. According to the wiring diagram it feeds from a different way by itself. At first I thought it might be a fuse, but beings the cluster lights work, I have kind of ruled that possibility out.

Do you have a 1980+ 240D?

The 240D uses a fiber optic spider behind the rocker switch panel. The rocker switches have fibers extending back to the spider. There is a single bulb at the hub of the spider.

The AC wheel is on its own bulb.

Carefully remove the two outermost switches by slipping a thin screwdriver blade between the wood and the bottom of the switch. This part of the switch flexes and allows the switch to pop out. Now put your fingers in the holes and pull the panel straight back from the dash.

Now follow the fibers (they look like black wires stuck into the connectors) back to the spider. It is clipped to the left side of the console internal framework.

While you have it all apart, get a q-tip and alcohol and clean the ends of the fibers.

more detail in this thread:
I can't find the spider! ('83 240D)

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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

I have looked thru the opening there several times this last week, but I was not able to spot the spider. Once you unclip it, will it pull back some?Does the bulb just pull straight out like the other 1.2 w frosted bulbs?