My "new" 300sd has functional gauges, but the engine temp gauge is not working. Stays at 0 degrees C, no matter how long I drive. From searching posts, looks like its either the gauge itself, or the temperature sensor. The sensor only reads ground right? Im wondering if I could clean the contacts and possibly fix it that way. My question is, where is this sensor located? And if I ground the wire going to the sensor, will my gauge measure in the red?

I also have no fuse in #13. Tried putting one in and burned instantly. Would this have any effect on the sensor?

Thanks!!!

If it's the OM617 engine the temp sender is between the #2 and #3 glow plugs in the head, IIRC. Look at your fuse chart and see what else fuse #13 controls. Sounds like you will have some wire tracing to do.

If I am thinking correctly, the sender does connect to ground using a temp sensative restsitor. The higher the temp, the less resistance.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Great! thats what I needed to know. I will try grounding the temp sensor and see if she "overheats".

Oh and my fuse chart is gone. My 79 still has the paper chart but not the 81 - since they are different body styles, will the 79's chart be accurate?

Thanks again!

According to my manuals on CD, fuse 13 (8 amp white) is for hazzard flasher,clock, radio, & central locking system. All gauges get power from the same fuse, so if any work they should all be getting power. Try grounding the temp sending unit wire at the sender. If gauge goes to full hot, sender is bad, if it doesn't move check wiring, instrument cluster printed circuit board, & gauge.

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82 300SD 202K
82 300SD 233K
83 300TD 340K
82 300TD 98k euro (parts on the hoof)
85 300TD 282K
83 300TD 197K