I presume you will take a test on the bench.
There is only one power connection going into header and from header you have three more green wires, two to mirrors and one to the switch. If you connected wires on the bench in same way, then only one connection from battery to green header should be fine.
Earth is somewhat different. In wiring diagram you have three ground connections. One to each mirror for heating elements in them and one to the switch. These are not connected together.
As i see it, if you want to test the motors in the mirrors you need to connect only ground/earth from the switch. On the other hand if you want to test heating elementa you need to connect earth from each from mirrors respectively.
The loom is now assembled in such a way that all lives (green) are all connected together at the 'juntion' between mirrors and switch as per picture earlier in thread here:
Manual to electric/heated door mirrors possible?
The two from RHS/LHS are joined at a spur/ that leads to the switch. I do remember that only two greens were cut from the donor cars header and in fact they were joined together with the switch live with a crimp and some tape. Had there been a separate live for the switch direct from the header, I'd have had three wires to cut, no?
As for the earth, pretty much the same. I did not cut from the header that was behind the passenger airbag blank, I cut them short before getting to the header. I have assembled the loom in the same fashion for the lives - the two earths from RHS/LHS join at a spur that also goes to the switch.
As my car will have no earth to the switch (as it only had manual mirrors) I assumed that by joining the earths from RHS/LHS with the switch would provide ground for the switch and all would be earthed at the relevant point in the car as earth is coming from the existing earth from my RHS/LHS heated mirrors.
Same goes for the live - fed from existing heated mirror wiring.
I don't have a bench to test, I was simply going to remove the battery and place it all on the garage floor. I was then going to tap in to both lives/earths from RHS/LHS and connect to the battery. My assumption being that as all lives/earths are joined, that would be fine.
Am I mistaken?
If you have already finished everything, why dont you just plug the new loom into the car and test each mirror whilst holding them?
Whats the worst that can happen, blow a fuse?
At least you will be able to try the full range of movement with the switch.
No real reason, I guess. I just wanted to make sure that they work before installing them. Didn't really want to go the length of removing speedo, door panels, etc only to find they didn't work!
Maybe best to test before hand was my thought........oh, and the switch is just dangling on the switch end of the loom so I should be able to test full movement outside of the car without installing it all.