air con fault '89 300se

[Glenn Smith]

I've just converted a mates 300se to use R134a, expecting it to run (was empty of gas before) but I have no power to the compressor, pressure switch is ok but only has very small voltage to it, does anyone know what voltage should be here? also can't find a wiring diagram, any one know if it's the same as a 124 model ( which i have diagram for) anyone had a similar problem or know of a weak link, trying to save time on the diagnosis.

cheers

 

[Glenn Smith]

problem found, traced to compressor control unit, has burnt tracking and melted resistor and blown transistor.