tedpreme

Hey guys. I recently got an 2008 IS250 w/ nav. I've noticed that it gets really hot when the AC is off. It feels like engine heat escaping into the interior. I was wondering if this is normal. It is almost unbearable to drive without my AC on, even on cool nights.

Is this normal?

dmvp29

I keep the A/C on almost year round except for winter (obviously).

There's no reason why you should have the A/C off in California during the month of July.

tedpreme

Yea. I keep my AC all the time as well but it bothered me that so much heat is getting into the cabin. I was wondering if its normal because I just bought this car used. I want to address all the issues before my warranty period ends.

jgbackes

iTrader: (2)

Nope not normal. My guess is that the Air Mix Control Damper is stuck/broken/disconnected. Check all of your fuses.

RDIS250AWD

iTrader: (7)

minus the winter my AC is always on everytime I turn it off I always end up turning it back on within 2-3 minutes

tedpreme

thanks for the advice. Ill be sure to check out the air mix control damper. I'm just curious if anyone else experience engine heat getting into the cabin when you turn your ac off

KillaIS250

iTrader: (1)

I never turn my A/C off either here in the CA summer just because once you turn it off it takes no time for the sun to start heating you and the cabin up and making you feel hot again

JasonChang

iTrader: (7)

I always scroll down the windows when I'm lower then 40MPH, if I go more than that I'll turn on the AC. The main purpose is for the fuel efficiency. I rather suck the dirts and clean the interior more often than turning on the AC ALL the times and wasting the energy and gas. btw, CA really is hot now!!! my hands become darker then it was.... got burnt by putting on top of the steering wheel most of the time. Lol

UniSlayEX

yeah, I used to wonder the same thing, but that's just how I am.

I keep the A/C between 72-75 and always on auto. If the weather is the same out, I half open all windows and let that breeze in. And if I want the hot sun, I just turn on the seat fan lol.

bob4256

iTrader: (17)

I drive around south FL without the ac on and the windows down. Call me crazy but I dont find it to be THAT hot.

My0gr81

Air damper is set to recirc by default, so the damper is closed, not allowing any external air flow even when the A/C is off. I had mine changed to manual, so I can chose if I want fresh air or recirc and it will remember it when you start the car. Fresh air setting with fan on, gets the air circulating even if AC is off.

viprtwo

iTrader: (15)

how do you change that setting? my car is the same way.. annoying.. since i always use fresh air.

jgbackes

iTrader: (2)

Below is a test you can run on the server motor itself. The terminals (pins) are in the server motor.

INSPECTION AIR MIX SERVOMOTOR

1. Connect the positive (+) lead from the battery to terminal 7 and negative (-) lead to terminal 6, then check that the arm turns to ”COOL” side smoothly.
2. Connect the positive (+) lead from the battery to terminal 6 and negative (-) lead to terminal 7, then check that the arm turns to ”WARM” side smoothly. If operations are not as specified, replace the servomotor.

In the '60s cars I had a valve that controlled the flow of hot water from the engine to the heater core. Now the hot water is always on and air directed over the heater core only when heat is desired. You might be able to pinch the heater's water hose. If that fixes the problem it's almost surely the servo motor.

My0gr81

It's a LPS, needs to be done by the dealer.

My0gr81

This doesn't help anyone since you don't mention what harness terminal 6 and terminal 7 are from.

the simpler way is just switch to fresh air mode and increase fan speed, hear the air flow, then switch to recirc, and you will hear and feel the flow change. Recirc does just that, the hotter it is, the worst you will feel as your own body will add moisture to the air increasing the relative humidity in the cabin. Fresh air will keep the RH down, and bring in a little colder air as it moves through the ventilation system faster when the car is moving forward.