Toyota Avensis T99

Even if the heater matrix is hot the heater will produce cold air if the air mixing flaps are in the wrong place - perhaps the flaps aren't working?

Replacing the coolant thermostat should ensure the engine is reaching normal operating temperature. Is this so?

One heater hose should be as hot as the top radiator hose when the thermostat is open and the engine is fully hot. The other heater hose should be very slightly less hot.

If one hose is warm and the other is relatively cool, it is likely an air lock is preventing flow and it will need bleeding.
If both hoses are hot, the heater air flaps are set to hot but still there is no hot air it is probable the heater matrix is blocked and will need cleaning or replacing.

Perhaps the Avensis has a brittle cable like in the Highlander.
Please see
http://www.tundrasolutions.com/forums/highlander/32217-heater-quit-sort-of/
It's usually broken solder joints on a cable behind, and feeding, the temperature knob.
I repaired my 2002 Highlander yesterday thanks to this site.

Low coolant has created a bubble in the heating system, some systems need a vacuum pull to fully purge the cooling systems of air pockets OR there is a blend door that is stuck in the heater plenum not allowing the air flow across the heater core, general answers, don't know this car in particular.

this could be several things first make sure it is switching from cold to hot on the tempeture side of the controls may have a bad cable

check heater tap under bonnet and make sure it opens when controls set to hot and engine running

most likely the ac blower switch is bad.aka.tempeture control switch.

My Toyota is a 2007,avensis T180,a got problem with the heating,takes time till is warming up,so i have to drive the car for 2-3 miles to be able to use the heating,which i think is not common,also when i want to increase heating between that time to 22 or more degrees,then acceleration goes up it self with out to touch pedal with the foot.Please any help from somebody who know something about this.

check for clogged cabin air filter, located behind the glove box. See owners manual for directions on how to remove the filter.

had air conditioing serviced and it does not blow cold

if its cold at 1 location all the time its probably got its gas maybe theres a vent not opening or a duct that has come adrift under dash,if its not cold in general you may need to get an AC guy to look at the fault but keep looking if you think something is simple to fix