the blower fan work fine when it does work (all speeds, blows heat
) but some times it does not work

 

I have a 2008 LT ext with a similar issue regarding the rear blower. Did you ever get this fixed? Yesterday it just stopped blowing during driving.

 

Problem found................ Because my 08 LT 85,000 miles, needs back shocks, the wire connector going to the rear blower fan lost contact. I just had to wiggle the connector with the key and rear blower on and it began to work. Thanks everyone.