Bmw 520,525 wiper problem !

I have now two Bmw,s a 520i 1991 and a 525i 1990. The problem with them is that the wiper speeds only work on fast speed. I have changed so far the the wiper moters and the wiper stalk swiches in side. But no joy. There supose to be two relay swiches. One at the drivers kick well and one under the back seat for the wiper control speeds. Please help I am going mad:banghead: