Just brought a 1997 e320 mercedes. how do i turn on the light for the heater panel. when it is dark. i can not see how to turn on the heater unless i turn on the inside light. should there be a light on the panel like the one on the radio that automatically lights up?

 

I have a 2001 E320 and had the same issue, but it is a blown bulb. Easy and cheap to replace. Need the removal tool for the dash unit ($8.00) and a new bulb (purchased mine at the MB dealership for $4.00. Slide the removal key's into the slot's at the lower corners of the climate control unit and slide the unit out of the dash. On the bottom of the unit in the front center is a socket for the bulb. Turn the socket a quarter turn and the bulb and housing drop's out. Replace the bulb and reinsert the socket back into the housing. Remove the removal key's from the housing before reinstalling in the dash and the unit just slides back in and lock's.