Read A/C problem not working
front a/c works perfectly but the back a/c does not even turn on any ideas what it can be ?

2001 marked the introduction of a more powerful V8 to the Yukon XL and the Denali trim. The full-size SUV has 5.3 L and 6.0 L V8 powertrains. In addition, you can choose from 9 different trims. Later models have 13 trims due to the introduction of basic 1500 and 2500 4WD and RWD trims.
Gas mileage comes out to around 14 mpg in the city and 18 on the highway. The '01 Yukon XL has 4 doors and seats 8-9 passengers, depending on which trim you choose. Max cargo capacity comes out to 132 cubic feet while max towing capacity generally ranges from 8000 to 9000 lbs., with some trims towing up to 12000 lbs.
Overall, the 2001 incarnation of the Yukon XL gets high marks for its engines and interior room. While this domestic SUV could use some stylistic refinement, the addition of the Denali makes the Yukon XL an even better buy. Pick up the 2001 model if you need something more affordable with reasonably modern features.
front a/c works perfectly but the back a/c does not even turn on any ideas what it can be ?
I have a 2001 Yukon Denali 6.0L and 92,101 miles on it. I have a recent ticking in the engine. Took it to a mechanic, who has never serviced our vehicle for us before and he said the ticking comes from the bottom of the oil pan area and since the lifters cannot be replaced on this engine I would need a new engine. Then I'm reading other people having ticking in their engines and others saying that lifters CAN be replaced. Who do I believe?! I'm very confused please advise and thank you!
My 2001 GMC Yukon Xl heater only blows cold but rear heater blows luke warm. Checked all fluids and all full
was heading to work this morning and I was coming around a turn. When I came out of the turn, I hit the gas hard, then my truck died. I tried to start it but It would crank, but wouldn't start. I checked to see if the fuel pump would prime when I turn the key to run, and it did, but when I check the fuel pressure, it showed zero, I thought maybe I was out of gas, so I put gas in it. I let it prime again and still no start. I have four codes on my obd scanner ,p0140, p0135 p0322, and p0327. Which is knock.sensor, 02 sensor and cat converter, but my cats have been hollowed out. I did just get the bully dog gt tuner. Any suggestions on what it could be?
When I turn the key I get nothing the car won't start but all the lights come on radio comes on so I can get a good power but no ignition the car won't start what could be wrong?
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: power
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Upholstery: cloth
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: coil springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-link
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: power
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Upholstery: cloth
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: leaf springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-leaf
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Memorized settings: driver seat · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: power
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Heated: front seats · Upholstery: leather
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: coil springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-link
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
4WD Type: part time · Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome · Skid plate(s): front and rear
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: heated
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Upholstery: cloth
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: coil springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-link
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Memorized settings: driver seat · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: heated
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Heated: front seats · Upholstery: leather
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: leaf springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-leaf
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
4WD Type: part time · Axle ratio: 3.73 · Locking differential: center
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome · Skid plate(s): front and rear
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: power
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: 40-20-40 split bench · Upholstery: cloth
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: leaf springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-leaf
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Memorized settings: driver seat · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
4WD Type: part time · Axle ratio: 3.73 · Locking differential: rear
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome · Skid plate(s): front and rear
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: auto-dimming
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Heated: front seats · Upholstery: leather
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: coil springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-link
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
Single disc in-Dash CD · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Memorized settings: driver seat · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable
Drivetrain
4WD Type: part time · Axle ratio: 3.73 · Locking differential: center
Exterior Features
Front bumper color: chrome · Rear bumper color: chrome · Skid plate(s): front and rear
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: power
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Heated: front seats · Upholstery: leather
Suspension
Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Rear Spring Type: leaf springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-leaf
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent
Air Conditioning
Automatic climate control front air conditioning
Airbags
Dual front airbags · Front side airbags
Audio System
6 disc in-dash CD · MP3 player: CD MP3 Playback · Premium Brand: Bose · AM/FM radio · Rear audio: rear volume control
Brakes
ABS: 4-wheel
Comfort Features
Steering wheel trim: leather
Convenience Features
Dimming rearview mirror: auto-dimming · Memorized settings: driver seat · Multi-function remote: keyless entry · Steering wheel: tilt-adjustable · Steering wheel mounted controls: audio
Drivetrain
4WD Type: full time · Axle ratio: 3.73 · Locking differential: rear
Lights
Exterior entry lights: security approach lamps · Headlights: Auto on/off
Mirrors
Exterior mirrors: heated
Rear Seats
Type: 60-40 split bench
Roof
Moonroof: power · Roof rack color: black
Seats
Front seat type: bucket · Upholstery: leather
Suspension
Air Suspension: rear · Front Spring Type: torsion bars · Front Suspension Classification: independent · Front Suspension Type: double wishbones · Leveling: self leveling suspension · Rear Spring Type: coil springs · Rear Suspension Classification: solid live axle · Rear Suspension Type: multi-link
Telematics
Satellite communications: OnStar
Third Row Seat
Type: bench
Tires and Rims
Wheel type: aluminum alloy
Windows
Front wipers: intermittent