CarForum.net - Car Forums, Automotive News and Community
Home Gallery Register Calendar Members List

Go Back   CarForum.net - Car Forums, Automotive News and Community > General Car Discussion > General Automotive Discussion

Reply
LinkBack Thread Tools
Unread 10-06-2012, 05:05 PM   #1
Junior Member
 
Join Date: Feb 2012
Posts: 11
Rep: 10 ChevyGuy29 is on a distinguished road
Default Any ideas what's going on with my AC?

I have several issues going on with my AC. Nothing big, it blows hot and cold, just a bunch of little nuisances. Here's a list:

1) If the car has been off for a while, say a few hrs, when you start it up again the air starts out barely blowing at all. As you're driving, it slowly increases and after about 10 min or so, it's back to blowing high again.

2) Something wrong in fan setting. It just always blows high no matter what you set it to.

3) If I'm just sitting there with the car running, not driving, and the air is turned off, the car heats up, but if the air is turned on, it doesn't do it and even cools back down if I turn it on after the car has gotten hot.

4) When it's turned off, all the air comes out down by your feet as if you have it on and turned to that setting.

Never had any of these things in any car I've owned before, so I have no idea what the issues might be causing them. Any suggestions?

ChevyGuy29 is offline  
Reply With Quote
Unread 10-06-2012, 06:27 PM   #2
Veteran Member
 
Mr Car Guy's Avatar
 
Join Date: Mar 2008
Location: Surrey, BC, Canada
Posts: 2,052
Rep: 186 Mr Car Guy has a spectacular aura aboutMr Car Guy has a spectacular aura about
Default

Quote:
Originally Posted by ChevyGuy29 View Post
1) If the car has been off for a while, say a few hrs, when you start it up again the air starts out barely blowing at all. As you're driving, it slowly increases and after about 10 min or so, it's back to blowing high again.

2) Something wrong in fan setting. It just always blows high no matter what you set it to.

3) If I'm just sitting there with the car running, not driving, and the air is turned off, the car heats up, but if the air is turned on, it doesn't do it and even cools back down if I turn it on after the car has gotten hot.

4) When it's turned off, all the air comes out down by your feet as if you have it on and turned to that setting.

Never had any of these things in any car I've owned before, so I have no idea what the issues might be causing them. Any suggestions?
I don't know what kind of car you are working on.

1 & 2)
Sounds like a fan resistor problem, or if you have auto climate control the inside temp sensor may be subject to whatever the current inside temp is and thinking it's not needing to change the fan speed. With climate control the fan speed is determined by the temp change needed, less difference in inside temp compared to desired temp means the fan speed is slow. Also some programming is done to prevent the fan from just blowing full speed right away so you aren't over powered on start up.

3) You say the "car" heats up. Do you mean the engine temp or the inside temp? If you mean the engine temp, that is normal for an electric fan cooled engine. If A/C is on then fans are running, you always have air moving to cool not only the A/C condenser, but the rad, so the coolant will not get up to the temp that the electric fans would normally start up at.

4) Do you mean that when you are stopped with the heater controls off you still have air coming in, or when you are driving? While driving with the HVAC controls off you may still have air moving through the heater.
__________________
2003 GMC Envoy 5.3

Mr Car Guy is offline Mr Car Guy's Gallery  
Reply With Quote
Unread 10-06-2012, 08:30 PM   #3
Spah sappin' mah susp!
 
Kenny McCormick's Avatar
 
Join Date: Jan 2009
Location: Earth...I think
Posts: 3,271
Rep: 96 Kenny McCormick will become famous soon enough
Default

1 and 2 could also be indicative of problems with the motor and/or switch. A weak blower motor will take it's dear sweet time to spin up, maybe even requiring a boost from the natural air currents that flow through the ducting from the cowl vent in front of the windshield. 2 could be caused by a bad switch or bad resistor that only works on high/is shorted out. My Nissan had that issue, fan was either off or full blast and that was why.

3 is entirely normal for a car with e-fans. They all do that. It's partially to compensate for the extra load on the engine, AC compressors sap quite a bit of power after all, and partially so the condenser gets airflow. This airflow, due to the condenser being mounted in front of the engine's rad, will aid engine cooling regardless of whether it needs to or not.

4. No idea why it blows out from the floor vents, but if you're moving, a bubble of high pressure air will form at the base of the windshield. Coincidentally this is also where the intake is for the HVAC system. On my F150 the airflow through the system from this pressure alone is equal to the fan being on low when I hit ~40MPH. How strong this flow is depends on the car's aerodynamics and forward speed, but they all do it.
__________________
Tired Iron ain't got no time to wear out...

My rigs:

1985 Ford F150 | 4x2 | 300ci OHV inline six | 4-speed OD manual | 310K | No power brakes | Running 100% - It hasn't driven this good in 15 years!

1984 Ford F150 | 4x2 | 300ci six | granny four | 3.55 rear end | 210K | Brakes shot. Rear drums are doing most of the work. Not fit to drive due to that.
1997 Ford Explorer XLT | 4.0L Vulcan V6 | 5-speed automatic | shift-on-the-fly 4WD | 210,000 miles | Running 95% - Needs brakes on all four corners + bald tires
1989 Ford F150 | 300cid six...again | 5-speed | 4x4 | 160K | Needs brakes done as well. Oi!

Kenny McCormick is offline  
Reply With Quote
Unread 10-06-2012, 11:13 PM   #4
Now accepting bribes.
 
lautinjr's Avatar
 
Join Date: Oct 2007
Location: Currently Las Vegas
Posts: 4,311
Rep: 193 lautinjr has a spectacular aura aboutlautinjr has a spectacular aura about
Default

Your cooling fan isn't kicking in unless the AC is on. Either you have 2 fans and coolant not kicking the cooling fan on, only AC kicking both on. Or could be you have 1 fan and it only kicks in with the AC. We need a year make model.
__________________
Please help reduce our mini van population and wear condoms!

lautinjr is offline lautinjr's Gallery  
Reply With Quote
Unread 10-06-2012, 11:39 PM   #5
Junior Member
 
Join Date: Feb 2012
Posts: 11
Rep: 10 ChevyGuy29 is on a distinguished road
Default

Sorry guys...it's a 93 cutlass supreme. It has 2 fans.

Car Guy, it's the engine that heats up. It's only when I'm stopped and not moving for a little while that it does that. It heats up past the normal temp and gets fairly hot but then slowly cools back down as I drive and get air flowing through again.

Kenny, it blows out from the floor on high. It does the same thing off as when the air is on...it barely blows out at first when you start the car, but then increases as you drive. Doesn't matter how fast I'm going, it still blows out high on the floor as well. It's like when you turn the air off it still looks for a place to blow out and comes out on the floor.

Also, how you mention that a bubble of high pressure will form at the base of the windshield...the air sounds like it's blowing high on defrost at the bottom of the windshield but that's when it's turned off and blowing from the floor. That sound stops when you turn it back on

ChevyGuy29 is offline  
Reply With Quote
Unread 10-07-2012, 01:50 AM   #6
Now accepting bribes.
 
lautinjr's Avatar
 
Join Date: Oct 2007
Location: Currently Las Vegas
Posts: 4,311
Rep: 193 lautinjr has a spectacular aura aboutlautinjr has a spectacular aura about
Default

Cooling fan isn't kicking on by itself, and either both fans come on with AC on or just condensor fan. Culprit will be either, one of the temp sensors, bad relay, Blown fuse, or burnt fan motor. It should have 3 temp sensors only one controls the fan figuring out which one is tricky. Usually when you unplug it the fan will run constantly. Confirm fan motor is good before tracking other issue's. The vent issue is unrelated.
__________________
Please help reduce our mini van population and wear condoms!

lautinjr is offline lautinjr's Gallery  
Reply With Quote
Unread 10-26-2012, 09:12 AM   #7
New Member
 
Join Date: Oct 2012
Posts: 3
Rep: 10 joshtimber is on a distinguished road
Default

I am sure it is temp sensor issue which is not working the way it should be.
__________________

Increase Engine Power

joshtimber is offline  
Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 10:09 AM.

Shogun Interactive Development Copyright 2015 Shogun Interactive Development. All rights reserved.