When I turn on the a/c, no cold air comes from the vents and the engine revs up once every 3-4 seconds

2004 Chevy Tahoe. Hot air out of vents on driver's side, cool ...

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Jun 25, 2009 - Hot air from vents-driver side and cool air from vents on passenger side. ... The driver's side vents were blowing out hot air, and everything else wasblowing cold. ... you'll literally have to restart your tahoe/yukon at every traffic light to keep cold air coming ... I was also getting air only out of the defrost vents.

Hot air out front drivers side vents 05 escalade - YouTube

? 3:14
https://www.youtube.com/watch?v=5lnd8UNcx6M
Aug 3, 2013 - Uploaded by South FL Mud Club
Suddenly hot air started blowing out the air vents only on the drivers... ... is a very helpful video ,I wondering if this part number apply for my 04 chevy tahoe? .... I have cold air out of thepassenger side, but warmer air out of the driver's side. .... 2003 Tahoe No Rear Heat Fix, Suburban, Yukon XL Repair!

Heating and AC Temperature and Air Delivery Mode Door ...

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Driver/passenger air vents blow hot then cold when using A/C. Back to cold when you restart the vehicle. Upvote (35) ... 2003 Chevrolet Tahoe ... I have a 02 Tahoe ,and the heat system is working only on the ceiling side of the car when turn.

2004 Chevrolet Tahoe Blows Hot Air - Sparky's Answers

Plug the vacuum line you unplugged and the idle should come back. Change your air filter and the map sensor. check for correct coolant level and replace the coolant temp. sensor. This sensor affects cold starting and idle through the ECU (open loop mode, rich fuel mapping and 1200 rpm idle) It should go to closed loop mode in the ECU once engine warm up is achieved ( lean fuel mapping and normal 900 rpm idle). Do not unplug anything else till you perform an OBDII scan of the stored fault history

You probably have air in the cooling system. These vehicles are sort of hard to bleed it out. I would recommend taking it to a dealership. Or you could take the rad cap off and run it but you will need a large funnel, one that is tight when going into the fill hole on the rad. Warm engine up, the fluid will rise a lot and this is normal. Once the engine is at operating temperature and the thermostat has opened up (grab upper rad hose it will be hot) rev it to 2500 rpm for about 10 seconds then release the gas pedal. This will help get the air out you will see bubbles in the funnel. Do that a few times (4 or 5) then leave it idle for a bit, put the hot air on through the vents it should stay hot if it is then you can put the rad cap back on if it doesn't stay hot you still have air in the system. I do it somewhat like this except I built a special rad cap specifically for the explorers.

Try starting engine when cold and rad cap, and/or coolant return cap off, and turn heater on. Let engine run and add coolant as necessary to rad as /if level goes down, and allow engine to reach normal operating temperature, and wait for the rad fan to come on, 2 or 3 times. Give engine a slight rev for 5 seconds or so, every once in a while while doing this, just to increase flow and help expel air better. Keep an eye on coolant level while doing it, and add as necessary, then put cap(s) back on, fill bottle to proper level, and try that. If that doesn't work, I'd question if air hole in thermostat was positioned properly when new one was installed, if you have a V-6 engine.

Follow the Accumulator (round silver cylinder) low pressure hose to the fire wall. You will find the low pressure service port valve just before the fire wall.

Make sure you don't over charge the system, add small amount at a time and check the temperature every 3 min to 5 min by placing the A/C on max with the engine at 2000 RPM.

Once the temperature coming out of the vents are cold as ice with the engine at 2000 RPM. stop charging. So turn the recharge valve on for 20 seconds and then off then rev the engine to 2000 RPM for 3 min and check the temperature at the vent.

Once the temperature is ice cold, stop and don't over charge the system. Over charging the system will cause the A/C compressor to shut down and at worst break, causing a $500.00 repair cost.

Good luck and thank you for using fixya.

Did you run engine from cold, with heater on when you refilled the system? Try again, rad cap off, with heater on, and let engine get up to operating temperature, make sure you have good flow through rad ,leave cap off, until rad fan comes on to cool returning coolant to rad at least twice. Give engine a little extra rev, for 5 seconds or so, every once in a while to make sure flow getting through heater core, and add coolant as necessary. See if that helps, as it may just be an airlock in system. If your cooling system has any bleed screws incorporated, crack them once in a while as well.

Leave rad cap off when starting from cold, turn heater(not defrost) on, and top up coolant in rad as you go, to about an inch or 2 from top of rad. Let engine run with cap off until your rad fan comes on & off 3 or 4 times. Every once in a while, rev engine slightly for 5-10 seconds to help bleed air out faster. After about 3 or 4th time fan comes on, you should be o.k. to put cap back on all the way & fill bottle to proper level. Heat should be there now. Give it a try & let me know how it goes.

Try replacing the cabin air filter.

With engine cool, remove rad cap, top up coolant to 1" or 2" from top in rad. Start engine & turn your heater on, (not defrost) and let it run like that until it gets up to normal operating temperature. Keep an eye on fluid level in rad, & top up as needed. Let it run, until your rad fan comes on, & off, 2 or 3 times at least. That's telling you that the thermostat has opened & hot coolant from engine has returned to rad for cooling. Every once in a while while your waiting, rev the engine slightly for a few seconds, just to assist the circulation & help bleed air out. Feel the heater now & you should feel hot air coming out. Top up rad to 1'' or 2", put cap back on, all the way, top up your return bottle to proper mark/level, and you should be good to go.

Take cap off rad when cool enough to do so. Start the car with cap off & heater turned on,(not defrost) and let it run for a while, as in wait for rad fan to come on 2 or 3 times. Add coolant/mix as needed while doing so. My guess is that you have an air lock in cooling/heating system that hasn't been bled out yet. Once in a while just rev engine a little, for about 30-second to 1 minute to increase flow through system, to help bleed & circulation. You should start to feel heat coming. Only put rad cap back on after rad fan has come on after 2nd or 3rd time. Check return bottle & fill it to mark as specified. If that doesn't do it, take it back to guy who flushed it, he should know what he did wrong.