Wierd heater problem

whynot · Post by **whynot** » Sat Dec 07, 2013 12:45 pm

So it has gotten cold here in the pacific northwest this week, down below 20. Not cold for most of the country I know, but enough to cause the heater in the car to have a noticable issue.

When I have the defrost on in any fasion, the air is cool. Even after 20-30 minutes on the highway. Send the air to the floor or the dash vent and it is nice and hot. If I get the car nice and warm and switch to defrost, the inside quickly cools and you can feel a breeze from the back, that I think is just the air flow from the fan.
All the windows and doors are closed and the seals look good.

I know the AC plays a part in defrost mode to remove water. But it should not have this kind of change on the temp. What could be going on?

Also does the air recirc run by cable or vacuum on a 2003 SXT. There is no drag when switching it, so I am hoping that is normal.

NickKo · Post by **NickKo** » Sat Dec 07, 2013 7:15 pm

whynot wrote: Also does the air recirc run by cable or vacuum on a 2003 SXT. There is no drag when switching it, so I am hoping that is normal.

If I Recall Correctly ..... The cabin controls are run by vacuum.

I am guessing that is where the issue is. After the cabin (finally) warms up, your controls get "unstuck" and the defroster starts working normally.

When you say there is 'no drag' when operating the controls.... You should feel a bit of 'resistance' when moving from setting to setting.
Is that what you are getting ?? Or does the knob just move, without any resistance whatsoever ??
If there is no resistance, I would say that there may be an issue, with the cabin controls.

- Nick

whynot · Post by **whynot** » Sat Dec 07, 2013 11:25 pm

There is no drag on the control for fresh air/reirc. The rest I can tell are Woking. But I do not see why there is the lack of heat on defrost, unless maybe the heater core is clogging. I had the timing belt and water pump done when I got the car.

NickKo · Post by **NickKo** » Sat Dec 07, 2013 11:48 pm

Regardless.... If you have the heat 'on' in the red zone, the defroster should be putting out warm air.....Not cold.

The fact that the heater seems to work fine, and direct Hot air at your feet, indicates that the thermostat is working O.K.
My guess is that there is something wrong with the heater controls, causing the defroster to 'mix' the air improperly, when the controls are set to defrost.

I have never had this happen to me in a Neon before (fortunately), so it is something I have never had to diagnose.

I thought someone had recently started a thread on a similar issue with the heater controls, but I don't remember if it was on this site, or on Neons.Org.

- Nick

NickKo · Post by **NickKo** » Sun Dec 08, 2013 10:19 am

I got curious, and did some searching, and found a couple of threads with similar issues.

viewtopic.php?p=717061#717061

viewtopic.php?p=907626#907626

Hopefully, this will help.

- Nick

whynot · Post by **whynot** » Mon Dec 09, 2013 12:12 pm

Thanks, But both of those threads talk about air movement issues. My air moves well, all selections work and the temperature changes. My only issues are that I am not sure if the recirc door is working, but even if it is not, I can live with that.
When I go to defrost, the air comes out of the correct spot, but the air goes cool. Not AC cold, but not hot like it is at the floor.
That is why I am so confused. I can not see a reason for this type of action.

MichNeon · Post by **MichNeon** » Mon Dec 09, 2013 2:01 pm

The problem is not with the recirc. door, that door flips between outside air and recirculating the inside air with no outside air.
The problem most likely is with the blend air door, which directs/ mixes the airflow from the heater core or the evap core to get the desired air temp. Check the actuator, if it is working, the door itself or its pivot might be broken, or may simply be stuck. Or; it may be moving, but not all the way.
Btw, there is one more door, the mode door, it directs airflow to where you want it~ defroster, dash, floor or a variation of them. From your description, it sounds like it is working as it should.

Post by **occasional demons** » Mon Dec 09, 2013 2:42 pm

Agreed, if it was the recirculate, if stuck shut, the windows would remain fogged no matter what. The air still gets plenty hot with the fresh air coming in. The HVAC controls are actually designed to block the recirculate from working when in defrost mode.

whynot · Post by **whynot** » Tue Dec 10, 2013 12:27 am

So from the looks of the thread with the assembly, the blend door is above the gas pedal. I will look under there and see if I can see it. and see if it is moving.
But why only defrost? of floor heat, and vents is gets nice an hot, it is just the defrost that brings the issue.

Sorry I am not understanding it.

I will check it tomorrow. I can feel drag on the temperature control when I turn it. And at the floor I do get a good temperature change.

Post by **occasional demons** » Tue Dec 10, 2013 8:34 am

I would pull the HVAC cover and check the controls/cable(s) possibly something with the defrost mode is interfering with the air blend door. I don't think you can see much from underneath. You can see the cables through the HVAC hole.

viewtopic.php?t=49477

whynot · Post by **whynot** » Tue Dec 10, 2013 7:55 pm

how do I get to that without removing the entire dash like you have done?
Can I see anything by removing just the vents in the center, and maybe use a mirror?

Maybe this is why the previous owner sold the car

r/tguy02 · Post by **r/tguy02** » Tue Dec 10, 2013 8:31 pm

Nope dash has to come out. Def one of the shittier jobs to do on a neon

Post by **occasional demons** » Tue Dec 10, 2013 10:30 pm

That is not my car or pics. I just posted it to give you an idea of what it looks like behind there. You may be able to see a fair amount of what is or isn't happening through the HVAC hole once you take the bezel off like shown in BoKu's write up, that I linked at the bottom of that post.

2GN.ORG

Wierd heater problem

Wierd heater problem

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