88 e300 temp gauge dead,how to test
 

hi ,well just bought a 88 300e in very nice shape. what a great driving car !well temp gauge does not work and was wondering if there is a test of the gauge itself.on alot of american cars i can ground signal wire at temp sender, for a quick second,and the gauge inside car will swing to hot. if so which wire do i try. if gauge inside car is bad is it a nightmare to fix? do i need to send out insrument cluster for repair?
also my climate control does not light, are they easy to get to bulbs?
tried the search ,but could not find the right words
THANK YOU Rich

The sending unit is a variable resistor. IF you ground the wire(green) from the sending unit to the gauge the temp guage should go to 240C.
The sending unit should have 110ohm at 60C(or 65ohm at 80C) if you have a volt/ohm meter.