PHASE 5

It's probably not the switch.
 
Sounds like the fan speed resistor pack is blown... pretty common.
 
It's located in the heater box, 3 wires attached and I think one screw holds it in.
 
Take out the glove box and you will see it.

fan resistor block will be shot, they use different size resistors to slow the fan speed down on the first few settings but the top speed setting uses no resistor so will work fine if your resistor block is stuffed
 
should be behind the glove box somewhere, a few screws hold it on, been years since i looked so memory is fuzzy

Contact Joe also  known as Bullfrog (go to members page) he makes them .

Put Tapatalk on your phone steve and you can upload directly from the phone.

all i did with mine was rub with 400 clean and spray with a glossy acrylic its been standing in the weather for 8 mths and still looks good

You must of had a bad setup you can tune them to the point of when and how the rear buckets pour the juice in  it's a case of finding a person that knows them well it sounds like yours was just using all 4 all the time. after it's last tune i drove from rosebud to beechworth 380 klm on half a tank using 98 oct and car was tuned for it.your beast sounds a bit hotter than mine but 95-100 wow thats poor.

I use to own a xc cobra back in the day (243) and change from the thermo to a holley vac sec and the only dif was the amount of fuel the holley used with no performance increase the thermo i have was recode about 10,000 k ago and runs like a dream as i have a machanic who loves them and can tune them well i can get 600 k out of a tank highway i was thinking of changing the manifold to just get a bit better responce without the cost of extra fuel buy changing to a holley with no performace change .
thanks for the responce. Adrian