My heater isn't working - 1994 Toyota Corolla

If you mean the blower motor, you would need to check for voltage and ground at the motor then work back to the power source.

eric may be right.I would bet on the blower resistor,but check all fuses-never assume anything.

This is not a heater valve problem, for one thing there isn't any such part in the model. The problem is a defective air temperature control blend door inside the air ducting.

Check the heater hoses that go into the firewall to the heater core, they both should be hot,if only one is hot and the other isn't,then the core is plugged. Remove the hoses at the firewall, buy of hose the same diameter,buy enough length so that you can flush away from the engine compartment, install it on one of the heater core pipes,using a garden hose with a jet sprayer slowly blast water into the hose, until you see clean water coming out from the other pipe. Remove the hose and install it on the other pipe of the heater core and repeat the process,you may have to do it several times to completely unplug it. This is a typical problem with a 3.0, 2 valve taurus,coolant looks brown and rusty. The entire cooling system should be flushed, if it isn't the heater core will plug again.

the plug sometimes melts or the heater switch try to check the plug connection,s

Hello! There are only a few reasons for this awful event to occur in early December...Either Hot water isn't circulating through the heater core, the thermostat isn't opening or the door that directs heat is faulty...Is the temperature gauge showing normal? Next, is the upper radiator hose hot and hard? If the last two answers are yes then hot water is circulating...The unit that controls the doors ...ie...heat or defrost is called an Actuator...Also the lever that opens the heater may be at fault....LETS ELIMINATE...
Is there defroster heat? If no the heater core isn't opening ..If yes then the actuator is the culprit...You can check the heater by feeling of each of the two hoses that come through the firewall into the inside...If they are both hot then the heater core is open and functioning...If one is cold the heater isn't being opened by the temperature control..Or it is simply blocked with gunk....It's a 99 and getting old...I would suspect that IF the upper radiator hose is hot and hard and the temperature gauge is normal all is well with with most components and the next step is; Are both heater hoses hot...Your going to have to narrow this down for me to pinpoint the cause...See diagram below of the door actuator allowing defrost heat to be sent to the heater floor duct...
Send a comment with results and or observations...Remember"your my eyes and my hands"...Guru ...Saailer





I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

You definatly have water inside the car. Pull the carpet back in the front and rear checking for water leaks. The only way frost can develope inside a vehicle is the presents of moisture.
The other possibility is your HVAC drain is plugged and water has built up inside the heater motor area. Have the drain checked and cleaned.

Without more information, I can tell you that you have a problem with your heater core. Check coolant levels and make sure you aren't low on coolant. If that isn't an issue, make sure your heater core isn't bypassed. In Texas, I see them bypassed instead of repaired because it hardly ever gets cold here. You could also have a dirty heater core that isn't allowing the heat transfer. The only other thing it could be is an issue with the temperature blend door/actuator. If it isn't opening properly to allow the warm air from the heater core to enter the ventilation system, you won't get hot air.

Here's a list of possible culprits:

Priority Action Part Type Cause
1 Inspect - Antifreeze Needed - Coolant Level Low.
2 Inspect - Heater Control Valve - Leaking or Faulty Heater Control Valve.
3 Inspect - Thermostat - Thermostat Stuck Open.

First thing to check is your engine coolant level - quick and free.
Since your blower works, my nominee for the offending part would be the Heater Control Valve, which redirects hot coolant into the passenger compartment heater core. Without hot coolant, the blower will just blow cold air, since the heater core isn't getting the needed flow of hot coolant through it.
There may also be a fault in the "Temperature Valve Actuators" (there is a right hand and a left hand version of these - one for each side of the car).
The Right hand Temperature Valve Actuator is AC Delco part #15-72971.
The Left hand Temperature Valve Actuator is AC Delco part #15-72972.
Their pictures are available in the online AC Delco Parts Catalog at:
http://parts-catalog.acdelco.com/catalog/catalog_search.php
Here are your parts search parameters:
Vehicle: 1996 OLDSMOBILE AURORA V8-244ci 4.0L F/I Vin C ID# 17739
Group / Subgroup: Heating/AC / Heater Core and Htr Control Vlv

Check your fuses and relays. Make sure the connections in the back of the lighter are solid, and ensure that your heater core isn't plugged.