I just discovered this nice little youtube clip on testing a series 2 PTU. Jump to about 6 mins in for typical resistance values between the leads... hope it helps . https://www.youtube.com/watch?v=uaqt69mFKGc
I watched that aswell, it's a long process I'd rather just leave the s2 ptu aside. And to Gunwarm, it never smelt nor did it ever get hot to touch. I was reading elsewhere and they reckon if you wire it incorrectly for a peroid of time it will be super hot to touch.
mine was wired incorrectly originally, it spent quite some time too hot to touch while the previous owner was trying to suss it out. once corrected though it has not missed a beat. I guess miswiring it is not a definate death sentance, I would not throw it away until it is tested in a car with S2 ptu setup and known good wiring
The S2 PTU has the inlet and outlet sides swapped over. Series 1 inlet is on the left and outlet the right, S2 the other way around. The 12v and earth terminal are originally on the inlet side of the S1 ptu, when you change to series 2 they are on the outlet side. That's why in the plug in adaptor loom you can see 2 wires going from one side of the S2 connectors to the other.