Two problems, AC and Putting in Drive

[Txsbigfoot]

I have a 2004 Trailblazer. Which has been a good vehicle up till now at 55M miles.
First problem is I am having a hard time getting it to go into gear when pushing down the brake. I know it has a switch but I do not know where it is or what it is called.
Second is the AC. It is having a hard time staying on the cold mode when starting the car. Sometimes I have to restart the vehicle for the AC compressor to stay running. The freon is not low. I figure a relay is getting bad but as above I do not know which one is probably the culprit or where it is located.
Any help on these two problems would be appreciated.
Thanks

[ScarabEpic22]

If you are having probs with your AC, is your fan clutch bad? It is a very common problem on TBs, so you might look into it. For the shifting out of park, sound like your brake solenoid is bad and needs to be replaced.

[dach95]

Do you use the hand breaks? I have problems with shifting out of park as well. However, someone here suggested that I get into the habit of using the hand breaks.

Now I park and pull the hand breaks. It helps with shifting out of park. I would shift out of park the release the hand breaks.

Since you have 05, you better have it checked out anyway.

[tbill]

a/c, low side pressure cycling switch may be going, been a common issue for the past few years on trucks/suv's.

the other issue may be a bad BTSI solenoid.