Heater temperature issue is250c

[Shaunomercy]

Hi everyone.

Discovered an issue today with the heater.

Put it to hi and it blows very hot. Set heater for 29 and it's blowing nigh on cold.

In short it's either bloody hot or cold with no temp variation between hot and cold.

Radiator is full of water before anyone suggests that.

 

Any ideas please.

 

Thanks

 

Paul

 

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[m4rkw]

What does the ambient temperature readout say?

Is there a point where it crosses a threshold and becomes hot/cold? You say it's cold at 29, what happens at 30, 31, etc? Is there a gradual warming or is there a single point where it suddenly blows hot?

[Shaunomercy]

30c it blows cold. Hi it blows hot
Paul

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[Herbie]

Is it just a heater or is it climate control?

If it's climate control and, for example, you've set it to 23C but the interior when you get in is, say, 30C, then the climate control will set everything to maximum cold in order to get it down as quickly as possible to the set temperature. Equally so the other way too.

[Herbie]

44 minutes ago, Shaunomercy said:

30c it blows cold. Hi it blows hot
Paul

If it's climate control and the interior was more than 30C then it's working as it should.

'Hi' basically turns CC off and just turns heater on maximum.

If interior was more than 30 and you set it to 30, then the CC is working to quickly bring it down to 30.

[Shaunomercy]

I tried it with the roof down Herbie.
Cold all the way upto 30. Once it turns to hi, it cooks you. It is climate control and I've tried turning it off auto too. No difference

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[Herbie]

Sorry then Paul, no idea mate.

[m4rkw]

It'll have a cabin temperature sensor somewhere that's probably malfunctioning, either that or wiring to it. If the reading from that sensor is too high the car probably thinks it's constantly 40+ degrees so will always blow cold unless you select HI which bypasses the temperature check and just says "make as hot as possible".

[Alfalfa]

Sheck the temp sensor, maybe the cable is disconected. Happened to me.

[m4rkw]

http://europe.toylexparts.com/lexus/242520/ale20l-aeflxw/494w/009/4/8715/877782d

Not sure if that's the exact right model but it's probably close enough.

[Shaunomercy]

http://europe.toylexparts.com/lexus/242520/ale20l-aeflxw/494w/009/4/8715/877782d
Not sure if that's the exact right model but it's probably close enough.

Is this easily accessible ? If it's the cabin ambient sensor ? Any advise would be appreciated
Thx Paul

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[m4rkw]

I'm not 100% sure but I think it's probably 88625K on that diagram (interior thermistor), in the dash somewhere. Look on youtube maybe there are guides showing you how to get to it.

[m4rkw]

This may be helpful: 

 

[Alfalfa]

2 hours ago, Shaunomercy said:

Is this easily accessible ? If it's the cabin ambient sensor ? Any advise would be appreciated
Thx Paul

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It was easy on my old is200, probably more or less the same on the 250, same location. But i dont think there was a tube on the Is200, only electrick conection.

[Beamish]

 

Hi Paul,

In the ISC the sensor is located just to the left of the traction control/gearbox settings switches at the left of the steering column. You can see the horizontal grill in the dash panel. I imagine it should not be too difficult to access from below.   

The original part number for my car, which is a July 2009 registered IS250C, is 88625-47021 and should not be very expensive from Lexus but perhaps it would be worth your while checking the electrical connection to the sensor before going down the replacement route.

 

 

Dec.