Its a function of the HL switch. I think around mid 68 was when the law was changed. A switch from a 69-72 should work and will give you PL while HL are on. If you start playing games with wiring you will have a problem with the HL being on in both positions unless you use one heavy duty diode to keep the current from flowing to the HL side when the PL are on.
no true - look at the diagram I posted - the jumper doesn;t affect the headlight terminal, so the headlight function doesn't change. Basically, you tap into the tail light power because it's powered up in both "park" mode and "headlight on" mode.
In addition, the switches are different for both years (68/69), so a new switch won't fit into your harness plug if you switched it. it's not a function of the switch, it's the wiring attached to it.
