MAX A/C Issue
Thread Starter
|
CO River Rat
Joined: Feb 2004
Posts: 3,209
Likes: 0
From: Lake Havasu City AZ
MAX A/C Issue
'04 Explorer with 4.6L and manual a/c - when **** is turned to MAX A/C the compressor locks on, but fan speed doesn't increase and the heater water valve actuator doesn't move; not sure if Inside Air position is on. This started yesterday; worked fine 'til then. Ideas???
Steve
Steve
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
The only thing that should change when turning to MAX should be the recirculate door should operate. the heater control valve should operate off a linkage from the temperature blend door so that it is operated when the door pivots to the full COOL position.
Check that the blend door moves properly and that the vacuum is supplied to the recirculate vacuum motor when the mode is set to MAX.
Switching the control **** to MAX has no direct controlling effect on the compressor operation or the blower speed although blower sped often changes due to the difference in inflow air resistance from the different inlets.
Check the vacuum line that comes off the control head and goes to the two vacuum actuators - it's likely leaking or the control has failed.
Check that the blend door moves properly and that the vacuum is supplied to the recirculate vacuum motor when the mode is set to MAX.
Switching the control **** to MAX has no direct controlling effect on the compressor operation or the blower speed although blower sped often changes due to the difference in inflow air resistance from the different inlets.
Check the vacuum line that comes off the control head and goes to the two vacuum actuators - it's likely leaking or the control has failed.
Thread Starter
|
CO River Rat
Joined: Feb 2004
Posts: 3,209
Likes: 0
From: Lake Havasu City AZ
There's no mechanical linkage between the temp blend door and the water valve; it's operated by a vacuum actuator. The temp blend door will be in full cold already if the temp **** is also on full cold. Also, MAX A/C locks the compressor on, so it does affect the operation in that you can't turn it off with the button.
Thanks for the answer, but it sounds like you may not be familiar with my a/c system...
Steve
Thanks for the answer, but it sounds like you may not be familiar with my a/c system...
Steve
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Took that straight out of the factory service manual. I guess the factory manual is wrong. I was surprised when I read it wasn't vacuum operated.
No, MAX A/C shouldn't lock the compressor on, that would usually cause icing. It continuously "enables" compressor operation which is still controlled by the low pressure cycling switch.
No, MAX A/C shouldn't lock the compressor on, that would usually cause icing. It continuously "enables" compressor operation which is still controlled by the low pressure cycling switch.
Logistics Pro
Joined: Jul 2003
Posts: 3,595
Likes: 52
From: Lawton, Oklahoma
ProjectSHO89 is correct in that the water valve is controlled by a vacuum switch that opens vacuum to the water valve when the blend door actuator is at the full cold position. If the lever came off or the vaccum switch is bad or vacuum leak then of course it would not apply vacuum at the intended position.
It sounds like your intake air door is possibly broken off, which is a common problem on the Explorers from that date range.
Max AC will enable the compressor just like any other ac system switch position but the intake air door will bring in air from inside the vehicle which causes the extra boost in air volume or percieved boost from the sound of the rushing air inside rather from outside.
If you had an Explorer Sport Trac it could have an entirely different syste.
It sounds like your intake air door is possibly broken off, which is a common problem on the Explorers from that date range.
Max AC will enable the compressor just like any other ac system switch position but the intake air door will bring in air from inside the vehicle which causes the extra boost in air volume or percieved boost from the sound of the rushing air inside rather from outside.
If you had an Explorer Sport Trac it could have an entirely different syste.
Thread
Thread Starter
Forum
Replies
Last Post
Tobnpr
1997 - 2006 Expedition & Navigator
4
Jul 28, 2016 09:09 PM
mech63b
1983 - 2012 Ranger & B-Series
2
Aug 6, 2006 12:23 PM
evan250
Cooling, Heating, Ventilation & A/C
1
Sep 18, 2004 04:54 PM
