Working up under the dash is a bear. I've been there a couple of times, had to replace the heater coil which is the very worst job I ever did!
Remove the glove box, then give it another go.
I find that I usually have to remove a few other things to get to almost anything under there! Be very careful not to mess up the heater door setting, it is easily bumped and knocked off kilter.
These cars are great but they were never meant to be worked on!
Get a factory manual, it is worth its weight in gold.