Hi I have a 2006 Hyundai sonata. AC worked fine earlier today, then only blew warm air. Please recommend how to troubleshoot/what tools I might need?

SOURCE: 2006 Hyundai Sonata brake light problem

there is a tsb for the brake switch in 06 sonatas. it must be adjusted or replaced by dealership. is your check engine light on, if so its probably code p0504

SOURCE: 2006 Hyundai Sonata brake switche

hyundai bumper to bumper warranty is 5yrs 60k miles with 100k powertrain for original owner. unless you have an extended warranty it is not covered. there is actually a tsb for adjustment on the brake lamp switch

SOURCE: ac in 2006 PT Cruiser

Sounds correct - 1400 bucks sounds quite steep tho - shop around.

SOURCE: ac is blowing warm air in my 2005 sierra 2500hd duramax. Any idea

Your system has R-134 Freon in it. the 134 is made up of smaller molecules than the old R-12. The R -134 permeates through the rubber parts of the system. If the system gets too low on Freon, the compressor will stop coming on.(low pressure cut out switch). Have the system serviced with an A.C. machine that can vacuum, measure the amount of Freon in the system, and add the right amount. The machine can also inject die. Later the die will show up under a black light.This will show any leaks you may have.

SOURCE: My 2006 Hyundai Sonata's brake lights are not working

try the brakelight switch, it is right near the pedal above the footpad