Yet another A/C question - 82 300SD

[tstarr]

I'm trying to get the A/C working after replacing the evaporator core last fall. Summers in DC are just too hot not to have A/C. I've got everything together and decide to stick with the R-12 based on the threads on this board. Take it up to an A/C shop and they tell me that the Auxiliary Fan doesn't come on and that, after putting 1 lb. of Freon in, the pressure gets too high to proceed. They indicated that there must be a blockage in the lines.

I've done the following:

1) Visual inspection - there is a small kink in the hose which sits near the aux. fan, (which I missed when changing things out), but that hose has been that way since the car DID have some cooling.
2) Did the check that the CD gave on the freon pressure switch. Got 15V on one terminal, nothing on the other. The CD indicated that was either a bad switch or low freon. OK - I know the freon's low, so this really didn't help.

I know I need to troubleshoot the aux. fan and fix that first. My question is - is the aux. fan problem enough to cause the pressure to go too high to proceed? I'm trying my best to avoid having to void the system (and its $70 worth of Freon I just bought) in order to fix the problem.

Are there any other obvious checks I need to do to try to fix this with minimum grief? In an ideal world, I'd find that the aux. fan relay needs to be replaced, then I could shoot more freon in and the world would be good again.

Thanks for any insights you might have on how to proceed from here.