I took my cluster out to see why my fuel Gauge light is always somewhere in the middle and the light is always on.

Also just a few days ago my Temp gauge wont move. just hangs down at 40*.

so here are the pics, and what i can't figure out is what the white box with the odd spring hanging out is.

also, the 2 screws i highlighted, are those the 2 screws that i should be trying to ground with the chassis to see if it fixes both gauges?

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Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Rheostat for the instrument cluster lights.

The screws are circuit board mounts

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Ok, so the rheostat. I have very dim lights, almost worthless. if i replace it, should it fix this?

Also, the 2 srews. i read that i should ground the 2 screws for the temp and fuel gauge to see if that fixes them. are these the 2 screws i should be grounding?

__________________

Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Yes, replacing the rheostat will fix your lights but the best option is to solder a jumper wire across those two contact strips.

Solder a "jumper" wire between the two brass strips on the back of the rheostat. That will give you dash lights that can not be adjusted but for me they are just right. Then check all the small light bulbs in the cluster using the continuity function of your multi meter.
I have used any of the screws that hold the three parts of the cluster together for another ground.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"