1978 450SL Temp Control Unit Not Working Properly????
 

Maybe my car is to old to get an answer, but I have to try.

temperature SL has the automatic temperature control system, the one with the temperature dial on the left and the function switches center with the compressor switch on the right (I attached a photo FYI). My problem is this; no matter where I set the temp wheel, or push any of the buttons (except defrost, which blows hot), the unit blows only outside air temperature. The compressor seem's to be working, and I pulled the wood off to check the connection's which seem ok. So...What's up?

Hello and welcome to the forum! I've attached a link to a tech article from our site that may help you. Other members will likely chime in as well and assist.

Mercedes-Benz R107 A/C Temperature Sensor ETR Switch Replacement | 1972-1986 - 450SL, 380SL, 500SL, 560SL | Pelican Parts DIY Maintenance Article