Heater/blower problems related to AC........I think!!

[marvo]

Hi folks

My beautiful 1.8L racing green 04 plate VVT has developed a problem with the heating/blower motor.

In switch postions 1-3 the blower runs at a high speed as if it's permanently on setting 3, on setting 4 it speeds up to max. I initially thought the blower resister was popped but occasionally the switch will work just fine on settings 1-4 with correct speeds but this is a rarity. The heater also has it's moments when it blows warm at first then gets colder or simply blows stone cold from the start. Other times it blows hot air with no temperature problems. There doesn't seem to be a pattern to it!! Switching the AC on and off has no effect on the blower speed but it does affect the idle.

The temperature gauge sits around 50% of scale once the car is warmed up and running which is a tad higher than usual I think.

When this first started I could also smell a faint burning as if a compnent had burnt out which is why I thought the blower resistor had popped but that wouldn't explain the hot/cold air thing.

It all began when I used the air conditioning more than usual over the autumn months.

Any suggestions would be appreciated!

Many thanks in advance,

Marvo (I'm a magician!!)

 

[oldcodger]

Hi,

Think I would agree with you, the problems are not related.

Also agree that the blower resistor could be the problem, it could be partially failing with heat or cold.

This attached page from the 2004 Corolla should be similar to yours and if you have a multimeter you could check it and also if powering the blower direct you could check the current it draws.

As for it getting hot and them cold, are you on rotary dials rather than a digtal contol panel ?

It could be the control wire to the heater box flap loose or the flap itself slipping, that assuming you do not have a problem with an air lock or partially blocked heater matrix.

Seems there is also a relay, so its contact could also be worn out  or it could be the speed switch itself.

When you switch the aircon on it should raise the rpm from tickover around 650 -800  up to about 1200.

hth

 

PS  if you see Flash22 entry at the bottom of this post he links to a Celica 2002 wiring manual -might be of help.

https://www.toyotaownersclub.com/forums/topic/192280-2zz-engine-wiring-diagram/

 

[marvo]

Thank you for the reply, my controls are the rotary type. They seem to be ok. I shall have a look when I get a weather window!