Anybody done the BLEND DOOR job?
 

AC blowing 140+ on my side and 45 on the passenger side. I'm getting a B0414 code. I'm told this job requires a complete dash removal and takes about 10 hours. Anybody done it yet?

Have you checked the blend door actuator motors? They are little steper motors that move the doors from hot to cold. I have not replaced them on a Hummer but I have on my Chevy pick up as it had the same problem.