ST185 heater either blows cold or hot. No in-between.

My AllTrac has had an issue with the heater since I bought it. If I have the heater temp turned all the way down it blows cold air, but if I turn it up one notch it goes directly to fiery hot air. There is no in-between. When we are in the car, I ask my wife if she wants to go to Antarctica or Africa.

I've never done any work on heating systems so I'm not really sure where to start. I don't know if it would be the heater core, the heater control valve, or something else? Doing a search for this doesn't really come up with anything.

Anyone have any ideas?

Check valve on the firewall on DS. Ull the cable connected to it. Have some one operate it n watch was happens. Its a startgin point

celica_gtx":82f37t4t said:

Check valve on the firewall on DS. Ull the cable connected to it. Have some one operate it n watch was happens. Its a startgin point

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Thanks. I will check that out this weekend.

Hi.

Did you ever get this problem fixed?!


Sorry to bring up an old thread!

I have exactly the same thing on my 185!



What I know:


Not valve at front controlled by the cable.
Not the control panel inside the car! (Replaced with one that works, and same problem).
All fuses and relays checked! (All of them!!! 1 by 1!!! All are fine! Yes I literally mean wvery single one!!).
All wires look to be intact.

The next thing I am going to try is the "climate control ecu" unit under the dash!

I will post up results as soon as it has been fitted.


My problem was like yours. (About 3 months)
Then it went to just blowing cold air (2 weeks)
Now the fan speed only runs on minimum for the first 3 buttons, and maximum on the last button! (1 week)!!


Also I love you Africa/Antartica comment.
My girlfriend got mad at me for the Antartica weather too!!



I will post results within the next week after I have fitted the new climate control ecu, and hopefully we can get some closure on this issue.



Regards, Antonio.

Hi GUYS!!


It is fixed!!!


It was the Climate Control ECU!
This is not the official name for it as it is known to Toyota as an: "AC AMPLIFIER".


The part number is:
88650-20722
88650-20721

Both part numbers are the same box.

Basically it changed the last digit after toyota stopped making them.

I had the one ending in 1 in my car and changed it for the one ending in 2. All works lovely!!

Also this is a right PAIN IN THE ASS to fit!!!


Awkward space!


It is basically the white box with 3 plugs going to it as you look under the dash towards the centre console.

I have pictures if you like, but they are too big to upload, but I can send them by email.


Also it is on a bracket which is hidden and it has to come out attached to the bracket!!


Otherwise you are going to brake clips and screw holes, then you will be f**ked!


Happy to help if anyone needs it.


I hope this helps one person at least!!



Very happy.


My woman will not be needing her blanket anymore!!