Aircon regas with RS24 and aux fan query

[whiskychaser]

Have been toying with the idea of fixing the aircon for ages. Its the old R12 but in view of the value of the car I was shying away from a total conversion to R134a. So I thought I'd give this a try. A local firm tested the system for leaks and put it under vacuum. Then they added some esther oil and refilled with RS24. Result: Nice cool air for only £50!!
Now the guy pointed out my aux fan hadnt kicked in. Having looked it up it should do as soon as you turn on the aircon. So I jumpered the contacts at the temp switch on the rad. Fan runs on high but not on low though I can hear the low relay click over. I'm concluding fan resistor is shot so a couple of questions:
1. Does the fan only come on low or high as well when the a/c is switched on?
2. I know Bentleys gives 91 & 99 eg C for the temp switch to throw low/high but after 10 minutes idling neither switch was 'made'. I dont have a thermometer handy so when realistically does the fan cut in?
3. Can you get at the fan to replace the resistor from the front or is it a rad out job?

Edit: Plse ignore 3. Found a very good write up with nice pics here:
http://www.nmia.com/~dgnrg/page_20.htm

[whiskychaser]

Have been toying with the idea of fixing the aircon for ages. Its the old R12 but in view of the value of the car I was shying away from a total conversion to R134a. So I thought I'd give this a try. A local firm tested the system for leaks and put it under vacuum. Then they added some esther oil and refilled with RS24. Result: Nice cool air for only £50!!
Now the guy pointed out my aux fan hadnt kicked in. Having looked it up it should do as soon as you turn on the aircon. So I jumpered the contacts at the temp switch on the rad. Fan runs on high but not on low though I can hear the low relay click over. I'm concluding fan resistor is shot so a couple of questions:
1. Does the fan only come on low or high as well when the a/c is switched on?
2. I know Bentleys gives 91 & 99 eg C for the temp switch to throw low/high but after 10 minutes idling neither switch was 'made'. I dont have a thermometer handy so when realistically does the fan cut in?
3. Can you get at the fan to replace the resistor from the front or is it a rad out job?

Edit: Plse ignore 3. Found a very good write up with nice pics here:
http://www.nmia.com/~dgnrg/page_20.htm

There is also a diagram of the pins on the 'low' relay on bmwE34.net - they arent very clear on the relay itself. Ive got 12V at pin 87 when engine is running with ac on so it looks like that resistor is indeed shot. That only leaves item 2 - how hot is hot?