cl500 w215 climate control problem

93blade

Active Member
Joined
May 9, 2013
Messages
36
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Location
sheppey kent
Your Mercedes
cl500 2002
Hi, would just like to share my experience and subsequent fix of an annoying common problem. drivers side vent would always blow warm when aircon set very low. Passenger side worked ok. reading through various forums, it all pointed to problem with the duo valve, which controls left and right temperature. this valve as many may know is extremely hard to access. you have to remove windscreen wiper arms and plastic scuttle panel attached to bottom of windscreen. I also found it better to remove the windscreen wiper motor assembly, only 4 bolts and a plug, it just lifts away. rather than try to repair valve assembly I bought a 2nd hand one off ebay and swapped the whole unit complete. once done, tested and found still the same fault.....:(
looked at fault code and still showing KLA A and KLA V B1418 fault and would not clear. after finding a wiring diagram decided there must be a wiring fault. removed plug to valve coils and tested voltage at each one with engine running and only had voltage on the left side valve. this wiring went back to a connector X85/1, apparently in L/H engine comp fuse box, could not find initially, but its actually underneath the fuse carriers. unplug the front connectors and lift out fuse and relay carrier after releasing retaining clip. What you'll find is a small inline connector with about 8 wires on it, mine was corroded on several of the pins. I cut the wires and bypassed plug by soldering ends together, but inline crimp would have done. put back together and checked faults, this time they erased ok. set the temp low and started car.......now working fine both sides.:D
 
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