A/c hot on one side cold on other
 

I have a 04 tahoe the driver side constantly blows hot air but the passenger side blows cold air when a/c is on! Called a couple of dealers but all they say is bring it in " we can look at it,probably fix for around 500.00" no one will tell me whats wrong. Can anyone tell me whats causing this and how hard is it to fix? Speedometer very seldom works also.

Welcome to the forum.

Sounds like the blend door is stuck or inop.

A/c hot on one side and cold on other
 

i have the same problem on my wife's 2004 Tahoe. it actually broke twice under the 3yr 36k mile warranty and once again at 38k miles. I bought an extended warranty and the dealership, Casey Chevy in NN VA, said it wasn't covered under the $1,400 bumper to bumper warranty I bought from them. wasn't that convenient? not only could they not fix it under GM's warranty but they wanted me to pay them to have a 3rd try at it. still broken today 2012. Anyway, i was told the same thing, bring it in and we'll look at it... as if they don't know whats wrong with it already. I was told a "door" regarding the HVAC system isn't closing which is allow heat to enter. find the door and figure out how to make it close. then come back on here and tell me what you did please.

The speedometer is a bad "stepper motor" in the dash itself. I just fixed mine myself. If you are handy with a soldering iron, you can do it yourself. That is by far the cheapest option. Otherwise your two options are to pull out the guage cluster and pay someone to fix it for you, or replace the whole guage cluster.

if it broke, then was fixed under warranty, twice, i would argue it hasn't been fixed...