Heater does not work, Help!

[Catalyst]

Well I started a thread about the same topic about a year, ago, but can't seem to find it, so I'm starting a new one. I've done some searching and found a few things I can check.

Here's the problem.

Heater does not work. Car is an Lxi, hatchback. Car does not blow air out of the vents, when the push-button selector is set to Heat. It makes noise, and there is air coming out of the floor vents, but It never really gets hot. The best I can get is luke-warm air coming out of the floor vents after the car is warm. When I slide the Cold / Warm selector switch, it functions, and moves the little hot water valve next to the middle of the firewall. The AC works great, and the car blows air out of the vents on any other mode than Heat.

Any help will be greatly appreciated.

Thanks!

[labeledsk8r]

you say air doesnt flow out of the vents??? like nothing?? i had a problem when i first bought my car that i couldnt get the blower motor to turn on... it was due to a resistor on the blower box... i will look up the exact name for it... its about a 26 bucks part that plugs into the box.. when they blow the fan wont turn on and blow the heat out... only thing is i doubt it can be that since you say your a/c workd great... i never had a/c but i think that it wouldnt blow for any option

[Catalyst]

you say air doesnt flow out of the vents??? like nothing?? i had a problem when i first bought my car that i couldnt get the blower motor to turn on... it was due to a resistor on the blower box... i will look up the exact name for it... its about a 26 bucks part that plugs into the box.. when they blow the fan wont turn on and blow the heat out... only thing is i doubt it can be that since you say your a/c workd great... i never had a/c but i think that it wouldnt blow for any option

Yep nothing comes out of the vents when switched to Heat, only luke-warm air out of the floor vents. The dash vents work great on any other mode than Heat. I am stumped.

[forrest89sei]

Yep nothing comes out of the vents when switched to Heat, only luke-warm air out of the floor vents. The dash vents work great on any other mode than Heat. I am stumped.

Sounds like a stuck Air door

Check out the 1986 Master Manual (PDF one)

[Catalyst]

Sounds like a stuck Air door

Check out the 1986 Master Manual (PDF one)

Thanks forrest I'll check it out.

[LX-incredible]

When "heat" is selected air should only come out the floor vents. The heat button is the same as a floor button. Look at the jdm buttons, it shows an arrow pointing at the feet... If you have the temp selector to hot, hot air should come out of whatever vent you have it selected for. I would check for water valve operation when the slider is moved. I've gone into further detail (several times) in a few of ahmad89's threads...

[LX-incredible]

Here's one: https://www.3geez.com/forum/showthread.php?t=60708 It even has some movies of how the levers should operate.

[LX-incredible]

Another: https://www.3geez.com/forum/showthrea...t=59810&page=4

[Catalyst]

Ok, Thanks LX-incredible, I'll go through further investigation tomorrow when Its light out.

[Catalyst]

Ok so I wen't and struggled with my heater some more.

Here is was I have established.

- Blower motor seems to function
- AC works perfectly fine.
- Heat slider control levers are connected under the dash, and the one in the middle of the firewall is connected as well.
- Heat control lever (in middle of firewall) moves, and so does the little screw thats attached to the lever, so thats functioning.
- Rec lever moves, functions
- Heat slider does affect air temperature coming out of the floor vents (Tested this with the AC on, slid the lever, and the air goes from Ice cold, to kind of luke warm
-Heater blows air out of the floor vents, but it never gets hot, just kind of luke warm / cold.
-Car gets up to temperature fine, temp gauge functions normally.


Its an 87 LX-i Hatch.

What else can the problem be? It's got me stumped!

[nfs480]

In heat mode the hot air should still come out of the dash vents, they do on mine anyway. Is it just that the air isn't warm, because then i'd vote heater core. Otherwise sounds like something is blocked.

[forrest89sei]

Ok so I wen't and struggled with my heater some more.

Here is was I have established.

- Blower motor seems to function
- AC works perfectly fine.
- Heat slider control levers are connected under the dash, and the one in the middle of the firewall is connected as well.
- Heat control lever (in middle of firewall) moves, and so does the little screw thats attached to the lever, so thats functioning.
- Rec lever moves, functions
- Heat slider does affect air temperature coming out of the floor vents (Tested this with the AC on, slid the lever, and the air goes from Ice cold, to kind of luke warm
-Heater blows air out of the floor vents, but it never gets hot, just kind of luke warm / cold.
-Car gets up to temperature fine, temp gauge functions normally.


Its an 87 LX-i Hatch.

What else can the problem be? It's got me stumped!

Clogged Heater Core? or the valve to the heater core could be bad

[Catalyst]

If It was something clogged in the cooling system, like the heater core, would getting a complete cooling system flush by a radiator shop unclogg the core or whatever is clogged?

Will I have to flush the system even If I attempted to flush the heater core myself?

Is there any easy way to test that heater valve?

[labeledsk8r]

If It was something clogged in the cooling system, like the heater core, would getting a complete cooling system flush by a radiator shop unclogg the core or whatever is clogged?

Will I have to flush the system even If I attempted to flush the heater core myself?

Is there any easy way to test that heater valve?

there are home flush kits i have used that work very well, there semi cheep you can find them at any auto store or walmart i think prestone makes one. its a chemical and you have the heater on for the flush so im guessing it goes threw the core aswell.. might be a cheep try

[Catalyst]

there are home flush kits i have used that work very well, there semi cheep you can find them at any auto store or walmart i think prestone makes one. its a chemical and you have the heater on for the flush so im guessing it goes threw the core aswell.. might be a cheep try

Ok thanks! I will get one of those kits and give it a try.

[labeledsk8r]

Ok thanks! I will get one of those kits and give it a try.

heres what the bottle looks like

i think it ranges from 5-8 bucks for it.. and its all you need... along with water and new coolent... mostly you warm the car up.. drain it... put this in then fill with water.... run 10 minutes... drain it... fill with water, drain it... fill with water again, run for 10 minutes drain... and then fill with your new coolent mix.. its kinda time consumeing but you will be amazed at the crud that comes out

[steveko]

I think it might be the Air Mix Cable out of adjustment or the door that opens up inside.

[Civic Accord Honda]

yeah u might want to flush it my heater was not working that great last year and then i flushed my cooling system this summer and when i turned my heater on this year it was nice and hot