Temperature fluctuates a lot

[Gebo]

I can have my temp set on auto 72. During say a 30 minute drive, the air will blow warm and them cold and then warm and then cold...

Where is the thermostat? I was wondering if I am doing something to interfere with its reading the internal temp of the car. What else to check?

 

[Trunk Monkey]

Looks like it's on the blower housing.

 

[NMuzj100]

I would bet the air mixer is not working correctly. This seems to be the most common error in the AC system. Search for the AC diagnostic.

 

[Gebo]

OK, here's what I got. It will go from 1 to 7 testing each component. Stays about one second on "1" and moves to "2" etc. I then pushed a combination of buttons and got these codes to come up in the temperature box on the NAV screen and they each stay one 1 second and scroll through over and over,

17, 19, 21, 26, 37, 47

Interpretation? 2002 LX 470

 

[NMuzj100]

Lotto numbers so you can buy a new 200?

Need someone with a 2002 FSM to peer into the AC diagnostics section.

 

[pjskibm]

So..what did you find out? My 100 is doing something similar.

 

[Gebo]

Still waiting on help. I Keep looking for Repair Manuals on ebay but haven't seen any. It is very frustrating, ain't it?

 

[Gebo]

More information...It has gotten down in the 40's the last few nights. When I get in my '02 and crank it, the front window immediately fogs up. I have to go to NAV and change AC to blow on Defrost. I have 3 other Lexus in my family an none of them do this.

Now, I noticed just while rinsing my LX which has not been driven in 20 hours and has been sitting all day with current outside temp of 63 that the mere rinsing the windshield and hood fogged up the entire windshield. My wife (doing the rinsing) said, "Is it supposed to do that?" I shrugged my shoulders and have brought her question to the experts.

Any ideas?

 

[Trunk Monkey]

The AC should be on automatically with defrost, it removes the humidity and moisture.

 

[Gebo]

It doesn't come on for a few minutes. I have to manually turn it on. The windshield shouldn't fog up in the driveway while we are rinsing a cold car, should it?

 

[Trunk Monkey]

All depends on temperature and humidity, in the car and ambient. If your car has been sitting in the sun the interior would be warm and the cold water on the glass creates condensate inside. Pretty normal science.

 

[Gebo]

All depends on temperature and humidity, in the car and ambient. If your car has been sitting in the sun the interior would be warm and the cold water on the glass creates condensate inside. Pretty normal science.

We washed all 3 sitting in front drive way and only the LX fogged up. I understand your point but I got something else going on. It is not a temperature difference. Some how it is moisture getting in. Hey, it is 63 degrees for crying out loud.

 

[Gebo]

Looking for some circuits

Where is my "rear evap temp sensor," "rear room temp sensor circuit," "solar sensor circuit," "rear air mix dampe position sensor," and finally my "rear air mix damper control sensor motor"?

OR what parts do I have to buy to fix these 5 errors?

 

[Trunk Monkey]

Is this in relation to your temperature fluctuating?

 

[2000UZJ]

If moisture is getting in while rinsing your LX off, you might have a bigger issue. Just saying. I'm pretty sure it's condensation and the LX being 90% glass around the cabin, that's a lot more glass than any other car.


In regards to the thread, does it blow hot while idling (cold or warmed up) ?

 

[Gebo]

If moisture is getting in while rinsing your LX off, you might have a bigger issue. Just saying. I'm pretty sure it's condensation and the LX being 90% glass around the cabin, that's a lot more glass than any other car.


In regards to the thread, does it blow hot while idling (cold or warmed up) ?

Well, the side glass and the rear glass did not fog up. Somehow something is happening in the front cowl area (I think).

I've never noticed any difference in idle temp. Just frustrating wide temp change.

 

[Gebo]

I don't know. Not being smart, but do you think the "rear" stuff could have something to do with it? I've only been in the Driver's seat.

I'm starting to wonder if I am beyond help...

 

[Trunk Monkey]

I'm going to say it is and you can keep all your HVAC issues in one thread for your ease.

Are these CEL codes you're getting or what?

 

[Gebo]

TrunkMonkey,

I don't know what a "CEL" code is. Post #4 in this thread has the codes I pulled from my NAV AC almost 3 weeks ago.

 

[Trunk Monkey]

Check Engine Light. I'd head to an LX dealer with those codes and they should be able to pull up the diagnostic in their online service manuals. I don't know what codes the NAV will pull, I'm only familiar with the OBD2 ECU codes.