Yeah I do.... Had the same issue with my '88 GTI - i.e. the front works the rear...
That was a stalk and if you can hear the pump but no water that means it's knackered...
I lost the front washers once but that was due to a trapped line when I shut the bonnet.... Took me ages to figure that one out!! & I doubt yours will be that as the rear washer line runs through the firewall - along the loom and up the c pillar so very unusual to get a trapped line...
Mind you thinking about it my rear stopped once and I found that the fluid was coming out where the rear sunroof drain holes are as the T connector behind the C pillar had come adrift....
Afraid its a process of elimination.... Until you find something!!