anon1m0us

Hi,

My heater in my GX470 2003 is not working! I am freezing. i have coolant. What else could be wrong and before I change any parts, I would like to test/verify if that part is broken.

HELP!!!

mrblister

The obvious would be a fuse or relay. Do you have any function of the controls. Do you have navigation?
If yes does that work. Need more information !!

RCsGX

Bad thermostat? Is your GX temp gauge in the middle?

anon1m0us

I have Nav. and all my controls work.

anon1m0us

"Bad thermostat? Is your GX temp gauge in the middle?"

How do I know if it is a bad thermostat? My temp gauge is in middle and it does not overheat or stay cold. After 10 minutes of driving it is in middle.

mrblister

So recap. Your climate controls work blower speeds operate and temp button allows you to raise or ;lower the heater temp. But you get no heat at all just cold air blowing. If the temp gauge on the dash is half way up you should be able to generate heat. If you drive the car for 30 min does the heater put out any heat? If not you may have a stuck open thermostat that is not allowing enough heated coolant to flow to the heater core, There also could be blockage somewhere else. Most of the time it winds up being a thermostat Keep us informed.

roemer7

Here's a great write-up about heating systems. This might help with a diagnosis.

http://www.agcoauto.com/content/news/p2_articleid/239

mrblister

Good read. Lots of things to check before going to a dealer

IanB2

Is your problem getting and keeping the engine up to temp, or with getting the heat into the cab? You say the HVAC controls work, so it blows air, but the air is cold instead of hot?

Take a second and explain exactly what the problem is.

anon1m0us

Yes, by blower speeds work, I am able to raise and lower temp, but only cold air blows. I can drive the car for 30 hours, no heat is blowing. The Car temp gauge is in middle and still no heat.

My question is, how do I know it is the thermostate without taking apart my whole car?

anon1m0us

My enginer temp is fine, it is in middle of the gauge. The issue is my car only blows cold air. No hot air blows, no matter how long I drive and even when the Enginer temp is in middle.

RCsGX

Not sure if this applies to our GX or not....

https://www.clublexus.com/forums/rx-...sn-t-work.html


Another way to enter diagnostic mode:

mrblister

You can enter the diagnostic mode by holding climate button and recirculate at same time then turn ignition switch to on [ do not start the engine ]

1) Simultaneously press and hold AUTO and recirculated air
switches. 2. Turn ignition on. All indicators will flash 4
times, at one-second intervals. Tone will sound when indicators flash.
2) A/C system will enter self-diagnostic mode. To end
indicator check, press and release OFF switch. Read codes at
temperature display.

The diagnostic will test all of your actuators that open or close for various heat & air controls.


I recently ran mine 2004 gx470 and I got two codes that were # 21 # 24 These are sensor errors you will always get those. ** especially in low light if you run test and its dark in bright sun light it may not give you those codes

You can also after its run through its diagnostic sequence press the temp button up and you can then repeat the test one at a time for every press of the temp button it will advance from 0 to 9

IanB2

I'm guessing you have a blockage in the heater core, might be fixable via flushing theheater core, I'd flush you're entire coolant system at that point though to get all the old stuff out, so it doesn't happen again.

anon1m0us

I ran the DIAG, and it says 00--which is normal