Air isn't blowing hard out of front vents

Poss defective blower motor, have it tested.

ck the cabin polen filter

Getting your system recharged at a dealership would be recommended but only hot air coming through the front could be an hvac problem, make sure that all your vacuum lines that run to your system are not crushed or unplugged, they will be located in the engine bay of your vehicle.

As per your problem mentioned.There are few solved help links to troubleshoot these problems.Go through the list and Click the link below:----
Air conditioner blows air but not cold air http://repairhelpcenter.blogspot.in/2012/07/air-conditioner-blows-air-but-not-cold.html

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Car overheats and Air blows hot at idle? http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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Heater blows cold? http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

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Heat blows cold on drivers side and hot on passenger side? http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html---------- Hot air on the driver's side vents only? http://repairhelpcenter.blogspot.com/2012/01/hot-air-on-drivers-side-vents-only.html

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2005 Chrysler PT Cruiser: A/C Blows Warm? http://whoisbyme.blogspot.in/2012/06/2005-chrysler-pt-cruiser-ac-blows-warm.html

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1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold? http://technoanswers.blogspot.in/2012/04/1992-toyota-camry-ac-control-light.html

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No heat, blower blows only cold? http://technoanswers.blogspot.in/2012/02/no-heatblower-blows-only-cold.html

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These will help.
Thanks.

Check whether the warm air isn't going in with the cold air .Coolant line that runs into the firewall on the passenger side of the engine which is toward the bottom half of the firewall on the passenger side. If there is warm air going into the vents with the cold air then it blows warm air. You may have to shut it manually because it gets stuck sometime. Check it out.

I recharge unit for your ac

Hard to read your question, do you mean it blows cold air out of the front vents and hot air out of the rear passenger vents?

If the air coming out of the front is just cool and not cold, and the rear vents are warm, you have low freon and need to have it serviced.

What pressure did you have? And Is the front of the compressor turning when you have this pressure. Also feel the two lines going to the compressor, one should be hot and one should be cold.

apology in advance, still waiting for the details from your repair bill.

Sounds like a blower resistor... you will have to take it to a repair shop. Isuzu is dumping its passenger vehicles entirely in 2009, and the Ascenders are basically GMC Envoy SUVs, though GMC will not honor any repair work on the rebranded Isuzus.

Best bet is to trade it in on a Toyota Highlander or Sequoia amd save yourself future headaches...