OVP and KLIMA issues

[Jettpilot]

I recently developed an issue with my 89 300e with aproximately 85k on the clock. The 1st issue is an unstable idle...not rough or surging just the occasional hiccup while idleing. I have also noticed that my ABS and Check Engine lights will occasionally go on during these idle hiccups. Performing a search these symptoms tend to point the finger at the OVP. I just came in from checking the OVP and the 10amp fuse is good. Could it still be possible to have a bad OVP and not blow the fuse or does my problem lie elsewhere?

Secondly my A/C has stopped working, for the first few weeks it would work occasionally but now it will not blow cool air at all. I do not hear the compressor cycling on or off but the blower motor works fine, and the refrigerant level is good. Since the problem was erratic early on I am hoping the problem is with the KLIMA relay. Is there any way to jump the KLIMA input pins to bypass the relay and see if in fact it is the KLIMA relay?

Thanks for your help,

Sam