Bunger has it backwards, setting 4 makes the least heat, 1 makes the most. Because the part in question is a resistor, fan speed decreases by dropping the original 12v input voltage by creating resistance which creates heat.

 

Direct quote from my recall letter:

"Why is your vehicle being recalled? - The connector module that controls the blower motor speed in the heat/vent/air conditioning (HVAC) system may overheat under extended operational periods at the high and medium-high blower speeds. If this condition occurs, there is a risk that the heat generated could melt the plastic surrounding the connector module, which increases the risk of a fire"

 

they dont mention what makes the heat. in high the resistors are completly out of the circuit and, i believe the contact resistance,all thats left causes that one connector to heat and melt from pictures ive seen posted here. as i posted b4 , the relay takes all the motor current in high.=zero heat from resistors.
in the next higest position the lowest value resistor is used which would creat the least heat for the resistors.
they,gm, gotta keep their story simple and believable!!
if the resistors caused the heat problem, 100% of hummers would be troubled, not the case...

 

Well, I guess you're right then, Bunger. I ran mine exclusively on position 1 and 2, always on. Very rarely ran on 3 or 4 unless to quickly defrost or defogger the windshield and then back to 2. Happythree may be right about physical contact resistance. When I soldered mine, I noticed the pins had some sort of coating on them.

 

contact resistance is/can be caused by loose contact by a connector not good enough for the rated current no corrosion needed.

 

I just got mine fixed. They had to order the parts but you should be able to schedule it now.

 

Finally got my recall notice today! About time. Wow I'll have heat again and maybe even a/c in time for summer! Woohoo!

 

i have no trouble but got my letter. i dont like messing with it with no trouble. if it aint broke,dont fix it!.
wonder if i can get the parts and save for later if/when i do have trouble?
ill call a dealer.

 

I got the letter yesterday that the parts were in.

 

I'm not impressed with GM. I registered my H3 on my.gm.com when I first bought it back in June 2015, and the website shows that my '08 Alpha is part of the recall, BUT...I've never received the first letter, nor have I received the second letter. I know that I don't need the letter for the recall fix, but if I wasn't a member of the online Hummer community, I would never have known about the recall issue.