Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
There are four main areas of concern I think.
1. Face vents. The ducting behind the dashboard needs to be modified to accomodate the three round vents as opposed to the two rectangular ones. One of the dash conversion reports I read said that it could be done with a sharp knife. It's probably best to make some adaptor plate though as it'll seal better.
2. The P1 centre part attaches to the dash with six screws whereas the P2 has a plastic surround that screws to the dash and then the silver bits attach to the surround. Of course the metal bits of the dashboard are in different places. If you work in a bodyshop you may be able to braze/weld new mounting points onto the dashboard without damaging the dash itself.
3. Heater controls you've already mentioned.
4. Supplementary instruments. The wiring is different on P2 and the way the instruments work - especially the fuel gauge. On a P1 the fuel gauge is stabilised by the main instrument pack and the gauge itself connects to that and the tank sender connects to the main instruments. On a P2, the instrument is wired directly to the fuel tank sender. From what I recall, someone did the conversion by using the P1 instrument in the P2 housing. I've not investigated it fully myself.
Other than that, you have other factors to consider like the placement of the switches. When I considered doing this, I though of moving the fog light switches to the centre console and the headlamp aim to a P2 switch unit by the main instruments but with the P1 instrument dimmer button. I then keep the P1 switch unit on the right side of the instruments for HRW, Fuel flap and odometer reset.