89 300SE AC Klima relay repair help
 

My AC has been intermitent. I have troubleshoot it from instructions on this forum with a wiring schematic and everything points to the Klima relay (0025451305) being at fault. All the inputs are good and the system cools well when I jump power to the clutch. There are not any apparent bad solder connections on the board. I see there are some online stores that sell rebuilt ones with a core charge to get the bad one back so someone is rebuilding them. Has anyone tried to repair these or determined which components on the circuit board tend to fail? I have some electronic ability and access to a good electronics shop at my work. If it is fixable by just changing an IC chip or somthing else it would save a bit of money. Anyone have a schmatic for the board?

Thanks for any help, though I would ask before I spend the money on a rebuilt or new one. Any opinion on the rebuilt ones?

Ray

Start by re-soldering all the connecions. Especially the ones on the relay and connector. The solder develops very small cracks - I can only see them when using a stereo microscope.

Thanks
 

Thanks Dave, I resoldered the entire board and so far it seams to be working OK. Ray