I'm about to beat my head against the wall on this issue guys. I've posted a few times on here and gotten some great help. This one has me stumped.

03H2 with 80,000 miles. Here are the 2 issues.

1) AC Blower will come on and blow full blast. HVAC set to Dash Vents works fine. When I cycle to Floor... Dash Vents decrease to about 15% of Max but I get nothing from Floor or Defrost. Same with defrost vents when I cycle to them.. nothing from Floor or Defrost and 15% still coming from Dash. Cycle back to Dash and Dash blows 100%. Blower keeps blowing full blast as I can hear it running full speed. HVAC actuator up above accelerator pedal that splits Dash/Floor/Defrost is cycling as Climate buttons are cycling so it appears to be working. It Goes from Dash (arm full back) to Floor (arm in middle) to Defrost(arm full back). So the Actuator is moving. But then how come I can't get Air from Floor or Defrost Vents and when I cycle off the Dash... and the blower keeps blowing full Speed... where the F*$@ does the air go? Its blowing but where is it going if only 15% coming out Dash and rest going where?

2) Problem 2... Not sure if related but I guess it is. Since only the Dash Vents really work and its summer here in Wisconsin I leave the Climate button on Dash. This works fine and blows hard and cold for about 10 to 20 minutes. But then somewhere between 15 and 20 minutes I notice the pressure/force out of the Dash drops to like 15% of what it should be. Climate button still shows Dash and 100% Blower speed. Blower is still blowing full speed as I can hear it. There is no drop in the blower noise. I get 15% from Dash and nothing from Floor or Defrost. Now if I shut of the climate for like 20 minutes... or shut off the ignition for 20 minutes and crank back up.... I will have 100% force from Dash vents... for 10 to 20 minutes and then this all starts again. Once this starts and Dash drops to 15% what it should be... I can cycle to Floor and Defrost and is the same situation as in Problem 1. Cycling moved the actuator as it should.... but it makes no difference in the pressure in the Dash, Floor, or Defrost. So where the Hell does the air go?

So in Summary... If the Blower is blowing at full force... and I only have 15% out of Dash and 0% Floor or Defrost.... Where the hell is the 85% of air going? And secondly... why would I get 100% from Dash and then all of a sudden drop to 15% and 85% of air "go to someone I can't find"? Where the hell does it go?

The actuator appears to be cycling when I press the button on Climate. so I am stumped. Any ideas? Anyone have this before?

hmmm?

 

have you tried to see if it does the same thing in heat?

 

for issue @2, your evaporator might be freezing up??

 

Hi... I had not tried the heater to see if same thing happens. Will try tomorrow.

 

Hi. thanks for the note. If the condenser was Freezing up... I should still get normal airflow out Dash vents right? Condenser freezing up shouldn't stop airflow should it?

 

I think it might stop airflow. I'm pretty sure the design is that all air always flows through the evaporator but the heater core does get bypassed when no heat is called for. Might be low pressure or low refrigerant (freon).

"A/C Low Pressure Switch
The A/C low pressure switch protects the A/C System from a low pressure condition that could damage the A/C compressor or cause evaporator icing. The HVAC control module applies 5 volts to the A/C low pressure switch signal circuit. The switch will open when the A/C low side pressure reaches 138-172 kPa (20-25 psi) as measured at the switch/accumulator. This prevents the A/C compressor from operating. The switch will then close when A/C low pressure side reaches 275-317 kPa (40-46 psi) as measured at the switch/accumulator. This enables the A/C compressor to turn back ON.

The low pressure switch uses refrigerant pressure to open and close a set of electrical contacts. When A/C request is authorized the switch is closed and shows normal status. During this state the switch will show 0 volts on the A/C low pressure sensor signal circuit. When A/C request is denied due to a low pressure condition the switch will be open. During this state the switch will show 5 volts on the A/C low pressure sensor signal circuit.

Heating and A/C Operation

The purpose of the heating and A/C System is to provide heated and cooled air to the interior of the vehicle. The A/C System will also remove humidity from the interior and reduce windshield fogging. The vehicle operator can determine the passenger compartment temperature by adjusting the air temperature switch. The vehicle passenger can offset the passenger temperature as much as 16.7°C (30°F). Regardless of the temperature setting, the following can effect the rate that the HVAC System can achieve the desired temperature:

 

Is your air blend actuator working?