MarkV Posted March 1, 2011 Share Posted March 1, 2011 Ok, so, my digital climate control started acting up and not switching to defrost, etc. So, I replaced the computer unit under the dash (I combined two and made 1 good one) that problem has been solved, now, as before the air still shoots out of the bottom on the floor, as well as whatever the selected vent is, either the defrost or out of the regular vents, it always seems to also shoot from the floor as well, how can I fix this? Link to comment Share on other sites More sharing options...
Larry Schramm Posted March 1, 2011 Share Posted March 1, 2011 Sounds like you might have a bad mode door actuator. Link to comment Share on other sites More sharing options...
NTX5467 Posted March 2, 2011 Share Posted March 2, 2011 When there is no vacuum to run the actuators, the default mode is defroster and floor vents, no matter which vents are selected on the control panel.The most likely cause is the check valve/tee for the cruise control, on the driver's side near the master cylinder. Follow the vacuum line from the cruise control transducer rearward a foot or so from the cruise control "head" (under the hood, driver's side fender skirt) and you'll probably find the check valve which is also the vacuum source for the hvac system (on the supply side of the check valve). There is probably a small crack in the plastic tee section, but not enough of a vacuum leak to really affect engine performance noticeably (the engine computer is trying to cover the additional air with more fuel). It was somewhat common for these particular vacuum tees to fail with time and age. If the GM dealer might not have one, they should be available on the "HELP" rack at the auto supplies.As it turns out, the default mode for most GM hvac systems which experience air ONLY coming out of the floor and defroster vents (regardless of selected mode) IF there is insufficient vacuum to run the actuators reliably. This doesn't apply to the systems which have electric servo motors to run the mode doors.Just some thoughts,NTX5467 Link to comment Share on other sites More sharing options...
MarkV Posted March 2, 2011 Author Share Posted March 2, 2011 Well you can switch the defroster and vents but it always seems to shoot out of the floor as well and even when I shut everything off I still feel either heat or cold air coming out. Link to comment Share on other sites More sharing options...
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