A/c blows warm air when car is on motion, but works well on idle

In normal circumstances the heater wouldn't begin blowing warm air until the vehicle has travelled 5 miles - call it 5 minutes. That's because the thermostat only begins to open at around that mileage/time and allows coolant to circulate around the engine. Before that - there just isn't any warm coolant in the heater matrix.

After 10 miles/10 minutes of normal driving the engine will be at its correct operating temperature and the coolant will be hotter - as will the circulating coolant in the heater matrix. That's when the heater blows the hottest air.

If you're sure that the heater has lost efficiency it may be due to air being trapped in the heater matrix/coolant system, or a blockage caused by limescale/engine corrosion within the heater matrix itself.

To remove any trapped air, set the heater to maximum, remove the radiator cap/coolant bottle cap and let the engine tick over for 10 minutes.

If the heater matrix is blocked/partially blocked, drain the coolant system, refill with plain water, set the heater control to open .. and let the engine tick over for 10 minutes. Drain it again.

Refill again with plain water and add a can of 'radiator flush'. Follow the instructions on the can of 'radiator flush'.

Drain again and refill with coolant/water.

If the heater is still inefficient then the only option is to replace it - and that's not an easy job.

Heat is blowing on passenger side, but cold air ... - RepairPal

repairpal.com > Questions > Dodge > Ram 1500 > 2002 Dodge Ram 1500

Dec 7, 2009 - When I turn on the heat, the passenger side is receiving warm/hot air but ... blow hot air on the drivers side and it would get cold right away. about a week ago... I have a 2008 Dodge Ram 2500 SLT. ... Regardless of the settings cold air blows from the left vent and on the floor on driver and passenger sides.

Temperature Blend/Recirculation Doors May Fail and ...

repairpal.com > Problems > Jeep > Grand Cherokee

2008 Jeep Grand Cherokee143,000Visitor. I get cold air on driver side and warm air on the passenger side. Upvote (29) ... right side air is always at the coldest. no heat on the right side and air temp will not change, left side works good. .... Models: · Honda Accord; ·; Toyota Camry; ·; Honda Civic; ·; Acura TL; ·; Toyota Corolla ...

Heating and AC Temperature and Air Delivery Mode Do

You need to fix the coolant leak, then refill and bleed cooling system, then you will get heat and cure overheating problem too

If your vehicle was running while you
changed a fuse, you may have fried the computer.
Try disconnecting the positive(red side) cable on your
battery. Desconnect it for about 5 or 10 seconds
then reconnect it. This will reset everything.
That is, if you didn't fry the system. You might
want to check that fuse you replaced. For future
reference, only change fuses with vehicle off.

Check thermostat .

low heat at idle is farly normal for camry, i had alot of complaints about th that at a toyota dealership where i worked

hi there it sounds like the matrix has gone it is at the back of the centre panel at the bottom when the engine is hot touch the matrix to see if its warm

It sounds like your AC unit could be overheating or even damaged.

AC units have a sensor that will turn them off automatically to prevent damage from overheating. If there is an insufficient amount of air flow, the unit will heat up, and then eventually turn off.

When the car is moving, more air is forced over the unit, likely keeping it cool enough to run, however, when the car come to a stop, it loses that air flow, and quickly heats up. Thus, the AC would work while the vehicle is in motion, and overheat and stop when the car is stopped and idling.

However, the AC unit could be completely blown. The cold air while moving could be just a case of air being forced into the car. Think of a house fan, the fast the wind blows on you, the cooler it gets.... Thus, it could be an illusion that the AC is working when car is in motion, when it really isn't.

Hope this helps.

low fluid level or heater control valve may need replace..check hoses going to heater core...if cold...between heater control valve and heater core..replace control valve

does it have a cold start injector seperate from the other injectors usually on the upper intake somewhere with a fuel line going to it