fuse :B :
 

Got a 1990 300 sl and fuse B keeps blowing. This fuse seems to supply into the engine control module.The legend on the fuse coves says air pump clutch ac clutchand kick down solenoid . I do not sense that any of these devices are the sourse of the problem because the fuse blows after the engine starts and I have diconnected the air pump clutch.Any thoughts would be appreciated tks tom r

if mem serves on 90 300sl the a/c starts automatically when you start car,so compr clutch may be your culprit.if you remove plug from compr then you can try it out.