Another repair we found was the A/C recirculate vent door, which is on the passenger side, right in front of the windshield. These parts arent available anymore, so you may have a hard time finding them. Even so, youd have to look long and hard to find a GM parts number for duct tape and hardware cloth. If you want cold air, take the time to find the parts to do the job right. Also worth mentioning: Check the seal at the back of the underside of your hood. If this seal is damaged or if you have a cowl-induction hood without the proper seals around the air cleaner, it will allow hot air to enter through this vent and make your system a little less efficient.