Heater no blowing hot?

welcome to the forum, feel of the heater hoses, see if they get hot. you may also have to check coolant flow through the heater core. It is also possible, the blend doors under the dash aren't working correctly. A faulty thermostat could be another issue?

This guide can help us

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

Please run down this guide and report back.

it was the heater core plugged up on my car BTW

i have a 1998 chevy blazer with a 4.3 v-6. One day i get in and the heater just stopped blowing warm air. The guage still get's up to operating temps but still blows cold air. The blower still blows hard and i replaced the radiator cap and it is always full of coolant.

your blazer might have a bad heating coil. My Uncle had a Blazer of the same year and his did the same thing and it turned out to be the heater coil

I have heat some times and others not at all. We have changed the thermostat and flushed the system twice. The radiator does not get very hot even though the gauge says 190, also the hose's do not get very hot. HELP

Test the water pump:

One way to test for a bad water pump is to squeeze the upper radiator hose when the engine is hot and idling. Careful, because the hose will be HOT! If you do not feel much coolant circulating through the hose when you rev the engine, the pump may be bad. The other cause might be a bad thermostat that is not opening properly (remove and inspect the thermostat), or a clogged radiator.

I have a 1998 chevy blazer 2wd 4.3 engine. Have no heat. We have changed the heater core, thermostat, blend door actuator and still no luck. Both heater core hoses are hot. Can feel the heat inside when glove box is out but not coming thru any vents as hot air. The air is luke warm. Please help. Brooke

probably blend door problem.

your gonna have to remove actuator and manually move door to see it that helps.

did you get right actuator? there are 2, 1 manual and 1 auto climate controls.

my 98 blazer has little or no heat, one of my heater core lines stays cold, if I raise the idle, heat seems to get hotter. do I have a bad water pump.

not necessarily, your themostat could be stuck. I would change the thermostat

I am unsure which one it is. Not sure on how to manually move the door. Where exactly is the door at?

certainly sounds less difficult, i will give that a shot first. thanks

I have a photo of the box it came in but it will not let me upload it with my message.

Yes most defininately

maybe reduce file size or change format?

Hi,
I have a 98 Chevy Blazer, 114,000 miles with a V6 engine. I have no heat. Just installed a new A/C Heater Control Assembly, still not working. Took it back to the mechanic and my radiator was clogged because a previous mechanic had put in a stop leak.
Bought a new radiator. Still no heat. Mechanic suggessted that the water pump might also be clogged because of the Stop Leak that was added.
Can I trust this mechanic?? What's next??
Thanks

If a stop leak was used, run the car to normal temp, then feel the two hoses going into the heater core on the firewall, be carful they should be hot!
If one or both are only warm, the core is plugged with the stop leak too. If they are hot try changing the thermostat!

Hey Merlin2021 you suggessted a new thermostat, I forgot to mention that the mechanic installed a new one already! Any other suggestions would be appreciated.

Thank you,
Gerry

I have a 98 Blazer ZR2 and the floor heat has not worked since have owned it. The same goes for A/C as well. When I turn the climate control selector to floor I hear the doors moveing but it just goes to defrost. Are the doors stuck or is the selector malfunctioning?

does it stay on defrost all the time? do you know if it is automatic temp controls?

[quote:908b700881="seabee26"]Interior problem
1998 Chevy Blazer 6 cyl Four Wheel Drive Automatic 100000 miles
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I have a 98 Blazer ZR2 and the floor heat has not worked since have owned it. The same goes for A/C as well. When I turn the climate control selector to floor I hear the doors moveing but it just goes to defrost. Are the doors stuck or is the selector malfunctioning?[/quote:908b700881]

It has manual climate control and defrost works as well as the air on your face. It just goes right to defrost when I select floor

sounds like a HVAC control unit problem not sending vaccum to the correct actuator. Or you are loosing vaccum at the actuator.

I have the same problem with my 97' blazer! Defrost only for all heat and a/c settings. If it might be the HVAC conrtol unit or the actuator, where are they located on the vehicle, and can you fix them yourself, test, replace, get used at wreckers????????

if your not sure how to test it, i would suggest going to a junk yard and getting a new HVAC control and seeing if it works.

Heater problem
1998 Chevy Blazer 6 cyl Four Wheel Drive

i have a 1998 chevy blazer one heater hose gets hot the other stays cold is ther a valve or what controls the water flow or what could be wrong we have changed the thermostate

Hi:
It could be the heater control valve or the heater core could be plugged not allowing coolant to circulate.

When driving, the engine temperature rises relatively quickly to around 190 then drops, rises again then drops. All the while, my heater blows cold air. Is the engine thermostat accessible to the average backyard mechanic? I live in Michigan and the temperature is dropping into the 30's at night already. I have not detected any heater core leak, at least not inside the truck. Thanks for any help you can give.

Yes the t-stat is easy to replace. However, before you do that, check something for me. If you are getting no heat at all, first make sure the coolant level is full. Next, with the engine running, hot, and the heater on high, feel both heater core hoses. Both should be hot.

Let me know what you find.
Joe

I have completely scoured the radiator and coolant system looking for problems. I have found none. I am starting to think about the coolant temp sensor is shot. We are not getting any heat inside the vehicle.

Did you check the thermostat and heater core. The coolant temperature sensor's job is to sense the engine temperature and the thermostat controls the temperature

I just changed the blower motor yesterday cause I thought that was the problem but its not I still get no air on 1,2,3, or 4 what could be the reason for this

See my link

Http://shop.advanceautoparts.com/p/bwd-hvac-blower-motor-resistor-ru1027/20972204-p?navigationpath=l1*14922%7cl2*15019%7cl3*15900

Look at the connections to it also, they might be melted/ deformed from excessive heat (which might be the entire problem, and not the resistor). The connectors are probably available too from the auto parts stores

Let us know how things are working out

The medic

Thanks

I have heat on fan speed three now, but my speedometer is now stuck at 180 top speed

i have a 1998 s10 blazer and it has no heat i changed t-stat and flush radiator how do i bipass control valve?

To the best of my knowledge, it doesn't have a heater control valve. If it does, it would be on the supply side heater hose. If nothing is there, then you have a blend door that determines if you get heat. What I need to know is this, have you tried flushing the heater core as well as reveres flushing? Next, with the engine hot, heat on high, do both heater core hoses get hot?

Let me know.

Hey guys. Take a look at the speedometer pointer to see if there's a little stop peg the needle is against. By the late '80s / early '90s everyone went away from the too-reliable cable-driven speedometers and switched to electronic ones driven by a not-so-reliable computer. Turns out they have been rather trouble-free, but what can happen is they get hit with a voltage spike during other electrical repair work. This happens most commonly when connecting a new battery.

The speedometer is driven by a "stepper" motor. It is not a spinning motor with brushes like we normally think of. A stepper motor has four electromagnetic coils that are pulsed with varying voltage and polarity to create a movable magnetic field for the pointer to follow. You can identify these by the fact that they stay where they are when the ignition switch is turned off. They don't go back to "0" until the ignition switch is turned on next time.

The problem with those voltage spikes is if it causes the pointer to go more than halfway to maximum, when the ignition switch is turned on next time, it wants to go back to "0", but it looks for the shortest way to get there, and that will be clockwise. The pointer runs up against the stop pin and can't go any further.

There's three ways to fix this. The hardest method is to disassemble the instrument cluster to the point you can push the pointer counter-clockwise by hand. An easier method is to connect a scanner that can access the instrument cluster, and run the gauge test sequence. Typically that positions every gauge to its 1/4 scale, 1/2 scale, 3/4 scale, full scale, then back to "0". The speedometer will try to follow those steps, and once moving counter-clockwise is the shortest way to the target, the pointer will go there, then follow all the other gauges back down. Some cars can have the gauge test sequence initiated by pressing certain buttons in the right order without the need for a scanner.

The easiest method is to simply drive the vehicle faster than half the maximum speedometer scale. That doesn't mean 90 mph. Speedometer faces never have "0" and the highest number in the same place. Typically 0 to 180 will cover perhaps 270 degrees of sweep. In my minivan the highest reading is 125 mph, and 45 mph is right across from it. "80" is across from "0", so according to my sad story, if the pointer got stuck on the backside of the stop peg, I'd have to go 81 mph, then the shortest way to the target for the pointer would be to go counter-clockwise, then from there it would follow the computer back to its commanded positions.

Sorry that I don't do a good job of describing this fix. It's much easier to do than to explain it.

I have the exact same problem and neither of the hoses get hot.