Looking at a Z1A wiring diagram, it looks like the PO and ON are wired to function alike. I think one wire could be unplugged to make it function as a parking light (all lights except headlight).
As far as my project, I'm going to have to do some serious mods to make it work on my '79. Still working on it...:S :S
The Kaw List:
Current: 79 KZ1000 A3 MKII, 78 KZ1000 A2, 78 KZ1000 Z1-R, 78 KZ650 SR, 80 KE175
Former: 03 KLX400SR, 99 ZRX1000, 82 KZ750 LTD, 80 KZ1000 A4 MKII, 80 KZ1000 LTD, 78 KZ1000 A2, 74 H-2 750 Triple, 78 KL250