a/c fades in & out
 

I have a 1988 560sl and the a/c starts out working fine but fades away until the blower is not working. It may come back on and it may not. Several years ago I had a similar issue and had it repaired. I have since moved and can't get back to the same shop. If memory serves me correctly he replaced some type of vacuum switch under the hood and it wasn't very expensive.Any help is appreciated...thanks

Sounds like you still have a vacuum issue.

I'm not sure I see how a vacuum issue could bring the blower motor to a halt.

Is the blower motor actually stopping?

the blower does come to a stop...the a/c unit reacts as if it's reached the appropriate temperature...

I think the blower would keep running even when the desired temperture is reached. It does not shut down completely like the AC in a house.

I imagine it could stop if the low-speed fan circuit had something wrong with it. It may just be adjusting down to low speed which is non-functioning.

If you put the temp wheel all the way to the blue side (cold) will the A/C continue running?

Sounds like your blower is malfunctioning.could be brushes.i had to replace my blower motor recently on my 87.the commutater ring where the brushes ride was completely worn out.same type symptoms you describe:)

I'm also thinking the resistance circuit that produces the low speed may be open.