My heater is not working?

it sounds like the heater core can be clogged but to be sure lets run down this guide to help fix it

https://www.2carpros.com/articles/car-heater-not-working

Let us know what happens and please upload pictures or videos of the problem.

thanks for the guide I used a garden hose and blow out the core works great now

Nice work, we are here to help, please use 2CarPros anytime.

water pump went bad replaced it after this the truck seemed to not even rise above 120 degrees maybe higher not real sure but never came up to normal operating temp. I replaced the thermostat. truck is now running normal. The problem is I can not get the heater to blow hot air. It blows but not hot. The heater core messed up in 2001 and it was replaced also. Still not sure what the problem is though any help would be greatly appreciated.


N. Stewart

First, try getting the engine warm and then find a bleeder on the system. Purge the system of any air.

Second, check the heater hoses to see if they are both hot.

It could be air in the system, the damper on a plenum could be not opening, or a valve on the heater hose from the thermostat is not opening and is comtrolled by vacuum, electrical or cable.

I Checked the hoses and everything seemed fine. I then checked to see if the heater core was stopped up. I am not sure if this is the correct way to do it but it helped. I got my air compressor and removed the heater core hoses by the firewall. I then put on rubber gloes and some goggles and stood clear and blew through each hole with the air compressor. Well long story short it worked and now we have heat.

Thanks again,

Nathan :D

The problem im having with my 1996 Silverado with 96,000 miles, the other day the heater quit blowing hot air and when i change the control postion the dash or any position it will only blow cold air through the defrost vents, the blower control (hi-lo) still works.
Any help would be greatly appreciated since it is winter and cold ........

look for a broken vacuum hose. this will allow the air flow to be distibuted to the vents, floor, etc. the cold air could result in, the thermostat being stuck open, the blender door not moving, or the heater core being plugged up. let me know, and good luck :)

I have a 1995 chevy 1500 work truck. Yesterday heater stopped working and temp gauge was fluctuating between 210 and 235. Occasionally heat would come back on and temp drop to between 150 - 210. Do I need to replace thermostat?

The thermostat is a good place to start as they are not too expensive and it's not unusual for it to fail with the mileage and age of your truck.
Next time you have the truck up to temp., open the hood and squeeze the upper radiator hose to make sure the system is holding pressure. Radiator caps can fail even sooner than thermostats or sometimes the seal can get contaminants on it from the overflow cycling fluid. At least check for pressure and when the truck is cool check to see if the cap seal is good and the mating surface clean. You might want to go ahead and replace it anyway.
The next thing to look at would be the cooling fan.
With the truck at temp, make sure the fan is coming on. The fan switch or relay could be bad. If you put the A/C on next time it heats up the fan should come on to cool the condenser, if you have 2 fans just the condenser will come on, and it should drop the temp. The condenser fan does not come on with the cooling fan switch, so don't rule it out yet.

Hope this helps and I will keep an eye on the post if you need anything else.

The heater in my 1994 Chevy Silverado 4.3L does not blow very warm air, does it have a heater control valve? if so where is it located?

Hey

This sounds like a blend door actuator has gone bad which is super common on those trucks, here is a guide that will show you how to fix it. Your truck does not have a heater control valve.

https://www.2carpros.com/articles/replace-blend-door-motor

With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.

https://www.2carpros.com/articles/car-heater-not-working

If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator.

The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.

Check out the diagrams (Below)

Please let us know what happens.

Cheers, Ken

My AC works but have no heat on my 1994 chevy silverado Yes I checked the hoses both are heating up, every time I adjust to heat nothing happened? So I came across this guide and it showed me the problem I replaced it and saved $$$ thanks guys!

Nice work, we are here to help, please use 2CarPros anytime.

Cheers, Ken

two nights ago I had great hot air from my heater in my 1993 chevy K1500 then when I got up the next day and started the truck only got cold air from my heater, I checked all the controls on my heater ? AC system and everything works except no hot air. what happened and how to fix . thank you for your time

Hi there,

With engine warmed up and heater on hot, check the heater hoses going to the heater core, if one warm and the other cool, i would be checking the operation of the heater tap, don't just trust the controller, the tap may be fault.

Mark (mhpautos)

I had a small leak in the coolant line that I didn't notice. Refilled coolant and nothing happened. So, while the engine was running, I gave the radiator hose a couple of good squeezes and boom! The heat kicked back on and is running perfectly. Even burns my face a little bit. Thanks guys. Thank God I didn't need to get as technical as some of your solutions.

Hi:

Thank you for the info. I'm glad to know you resolved the problem.

Take care and feel free to come back anytime in the future.

Joe