BMW Repair: Headlamp wash wipe, breakers yards, two different ways

Question
E30 325i SE

Headlamp wash wipe not working.  I have had both h/l wiper motors off and they both work when hotwired. If I remove the cover from the relay next to the screenwash reservoir and activate the relays the motors will click as if trying to work, almost as if I am activating the "park" circuit. I have had several relays including ones from breakers yards but to no avail. I have yet to meet someone with working h/l wash wipe.  I have had the lights switched on during my attempts to find the problem.

Regards, David  

Answer
Ok so what you know is
-when the motors are out (freespinnig) they work good.
-when you feed the same amount of voltage through a few feet of wire the motors can't take the load
What about giveing them voltage while they are installed to see if the motors can even take the load of being on the car.
are you sure the motors are getting power with the relay jumped?  it is normal to hear a click from a relay when the circuit is being energized and deenergized (it is a mechanical arm being thrust in one of two different ways.)
so
check for 12v from the relay
check the voltage source at the motor and compair,  big voltage drop implies bad wire no voltage drop and it could likely be a bad or coroded ground.
-cheers