Inoperative oil temperature gauge

[Eyvind Spangen]

The oil temperature gauge on my '90 200TQ doesn't work. How do I find
out if it's the sensor (BTW, where is is located?), the gauge or the
wiring?

One more thing: What pin on the 4-pin connector for multi-function
temperature sensor do you connect to ground to see the coolant gauge
run to the top and trigger the auto-check warning? 

The 100/200 Bentley is somewhere in the mail, but in the meantime, I
ask the stupid questions here.. :-)

-- 
Regards,
ES