Hello, I would like to ask for help here. My problem: – Our SLK R170 PreFl 77,000 km (02/2000) 230k automatic has little power. – We just bought it. 🙁 ->But is not the first R170 with us. – In the MSG stood the P1235 (circuit valve). What have I done so far? – Umluftklappe removed and soldered the soldering points on the plug. – When I was installed, I saw that 3 cables were cut to the plug, just behind the exit from the wire harness (but was an old one). it CUT, since the cables were started and dirty). – Then I soldered the cables together again and provided them with a lubricating hose. – I removed the convection air flap, cleaned the grinding tracks and soldered the soldering points on the plug. – The error in the MSG is now also, without deletion, gone. – With such approx. 2000 (estimated) tours the compressor now switches on. However, the car still has little power. – Only the convection air flap is not closed. – On the pins are +12V and mass on . – At the control line I measure approx. +0,5V (in the stand gas) Someone can tell me which control voltage gets the flap and where they come from (schematic). Although I ordered a used air valve, but it takes a few days to get there. Thanks and greetings … Jörg