I am a new owner of a 500 SEC and I am trying to fix a couple problems with the car and could use some technical assistance.

Problem 1) The car intermittantly idle's at 1700 RPM's for no apparent reason. I have had the idle jump from the normal 600 RPM's to 1700 while sitting in traffic. I have heard the the fast idle relay is faulty on these cars and there are also problems with the OVP. I have checked the fuse in the OVP and it looks fine. Is there a way to trouble shoot this so I don't end up buying unneccesary parts?

Problem 2) The heat does not work all the time. If it isn't working I can turn the car off and on and it will work fine. I checked the mono-valve and the rubber gaskets seem intact. I think the problem is with the vacuum switchover valve because the times the heat works I can hear the switchover work from behind the control panel. How would I make this work all the time?

Thank you in advance for your help and I look forward to reading any responses.