To me it looks like the "Wiper Amp" has the relays for the timing On/Off delays, The "B" is the ground and the "LG" is the constant +12v, "OR" looks to be the signal the amp receives when the wipers are back at the start position. Unsure exactly how the signal wires are working without having it there to have a play with, who knows whats happening inside that amp... But I'd experiment with shorting out the "BR-W" and "P" wires at the Amp and see if they come on high as a start, then look at removing it from the circuit.