R129 SL500 temperature gauge not working?

[IMD]

Hi all,

I've just noticed this morning that my engine temperature gauge doesn't seem to be working and sits at 40.

Is there an easy way to check this? I'm no electrician! I've yet to look at fuses, although I expect it wouldn't have a fuse to itself and everything else appears to be ok.

Any thoughts / suggestions / remedies would be appreciated.

Thanks

Ian

 

[grumpyoldgit]

Does the heater blow hot? If not it's more likely to be the thermostat that needs replacing. Mercedes seem to suffer from failed thermostats.

If the heater blows hot, it could be the gauge or the sender unit. Locate the sender unit and unplug the lead, bridge the two terminals in the lead, and if the gauge moves it's probably the sender unit that has failed. Ignition needs to be on and it may take several seconds for the needle to move, so you may need someone to watch the gauge while you bridge the terminals.