I'm really hoping it's the Tstat. it's an easy fix.

I don't think there's any easy way to test those doors other than doing the tedious work of removing the panels.

 

Okay, finally had the chance to work on the car again. The weathers been really crappy lately, been raining everyday. Anyhow, instead of checking the temp. or if the TSTAT is working, I just decided to replace it. It's a cheap replacement and I figured, the car being a 1999, it's probably due for a change anyways. Ran it for about 20-30 mins to pick up the wife(total 15km drive)....And still, the air temperature blowing from the vents are still not hot enough. The air is a bit warmer than before but not as hot as the temperature that I set it on.

I will flush the coolant this week hoping this will solve the problem. Hay..

I'm running out of areas to inspect, and it's almost 100% pointing out to a blend door problem. Got anymore ideas or areas/parts I can check that might be causing this problem (Lukewarm heat on both front and rear) before I finally tackle the "Dashboard/panel Removal"?

 

You know, I'm having a horrible time with heat in my 2000 too. When I first got the truck, it was blowing at best lukewarm air and the operating temps never got quite to where they should have been.

Replaced the tstat, now the operating temps get to where they're suppose to be. I get really really hot air out of the heater but it comes and goes.

I would have suggested a backflush but you show as both hoses being hot coming from the firewall. I did that last night regardless since both my hoses are hot and very warm/hot for the outlet, of course it didn't help my cause.

I see on here mention of a heater flow valve? I wonder if my 2000 has that? Searching the archives shows no results for it.

The picture you have that shows a tire - where is that exactly? I'm going to check mine too.

 

Mine doesn't even blow hot air at all. It would have been okay if the rear or front works. At least then I can set either one to high setting to heat up the interior. But like I said, either front or rear blows hot air. I don't really know if flushing will work but I'll do it anyways, hoping this will solve it. I'm just going through every single possibility before I disassemble the dashboard.

As for the picture that shows a tire, the tire shown is the spare tire. If you look under the rear passenger side, you'll see 4 tubes/hoses.

 

Same..got it w/ very little to no heat up front and warm air in back after quite awhile of highway time. Something up front moves and I can change from cold air to luke warm air...or if I run fan too fast its like it cools down the core faster than it can get hot. On hose(s) onside hot other luke warm at best scenario. Back Flushing this time around and prob get a new "T" set up?

I dunno..last winter was very difficult..this winter the expy will be warm. But like changing an alt out in "New Edge" cougar, it is quite time consuming to even get in there to inspect the blend door..hell should just change it out then for the hell of it right then regardless of the condition lol?

T Stat, Back Flush and pray that the dash can stay where its at. Is the general feel I get out of the various posts on the issue.

 

Mine goes through cycles, where it's lukewarm, to cold to absolutely blistering hot (hot in a way that it should be when on it's hottest setting) - all while never once changing the temp setting on the auto hvac controls. So I'm pretty sure it's not the blend door.

The coolant temp gauge stays perfect.

If the waterpump was going I would think my gauge would be going up or something. But it stays perfect once warmed up.

I don't think a backflush will help you either unless someone can chime in and tell us the inner workings of the heater core. Are there internal fins that get cruded up but flow through the core can still be good? (coolant unable to get through the fins...)

I have great flow through the core, doing a regular or back flush on just the core.


edit: some other details I forgot to add...

On the way home I turned on the rear heater controls since I never really checked what those vents do while I'm having this problem.

Even when my dash vents blow really hot air for a few moments, the rear vents are always blowing cold.

It seems like if I turn the heater completely off in the front and then turn it on again moments later it'll blow some warm air out of the dash vents for a very short period. I have the auto HVAC controls too.

 

The EATC (E_lectronic A_utomatic T_emperature C_ontrol) module uses an ICT (In-Car T_emperature) sensor to determine how much heated and cooled air to mix to meet the set temperature.

You can put the EATC into self-test mode by simultaniously pressing the OFF and FLOOR buttons, then pressing the AUTOMATIC button. The self-test mode will test the various componets of the EATC (including the ICT sensor) and display any DTCs found. Write the DTCs down!

Push the "blue" button to exit the self-test mode and retain any DTCs.

 

Ok so I start the sequence, a little cursor is moving around in the middle of the screen and then it displays every signal item possible on the display and does nothing elses - sits there with everything displayed. I sat there a second time for 5 minutes after letting it do this for 3 minutes the first time...

I must be missing something?


edit: or does that mean there are no codes?

 

I guess there's a whole bunch of us I guess having a similar or same issues - HEAT.

As for LBROWNE: No disrespect or to offend anybody, but do you mind starting your own thread. I'm trying to get solutions to my problem not solution for someone else' on my own thread. I have a Ford Expedition sitting in my driveway for 3 weeks now bec. the wifey (4 months pregnant) refuses to drive it to work because she couldn't tolerate the cold esp. in the mornings. We are all hoping that every one's heat issues can be resolved by the helped of the gurus or experts here. Good luck to you .

 

**tire screeches..

Guess Im done posting in this thread too...nuthin constructive to add.

Hope you get "your" issue resolved...

 

dbl post FTL

 

The heater controls could have been your issue too but whatever - Good luck. Cheers.

 

1999EBEXP:

I have been working on exactly the same problem you report.

By the looks of your picture (and THANK YOU for that), you have a 4.6 is that possible with EB? I have a 4.6 and it looks exactly like that. There are no heater hoses coming from the top of the front of the engine.

If you look at your picture, and the 2 pipes that lead to the rear heater core... the front-most one...

These have the special connectors on them. You can rotate the hose. When I let my Expy heat up, all the hoses near the front heater core are hot, but at this connector, the pipes are hot on both, but the hose is cold just after the connector on the front-most one.

I suspect that the pipe is clogged at the connector and it is causing a flow issue. Now, that's for the rear and I don't see any other problem for the front, but I get only a touch of heat on low fan and then none on a higher setting, so there isn't enough water going through it. The core isn't clogged on mine (it was tested), so I think the problem is a clog at the connector.

BTW, I have manual heat/AC and on my 99, there is no heater control valve that I can see or find, even though the part is sold at the auto supply.

Can you check those connectors on your vehicle and let me know what you find?

I don't know how difficult it is to get that connector off (I know I have to get a special tool), but I'm thinking of just cutting the hose above it with some margin, using a wire hanger or something else to clear it and then splicing it back with a flush connector.

Please let me know what you find!

Thanks,

Andy


Postscript to lbrowne: You said...
"Mine goes through cycles, where it's lukewarm, to cold to absolutely blistering hot (hot in a way that it should be when on it's hottest setting) - all while never once changing the temp setting on the auto hvac controls. So I'm pretty sure it's not the blend door. "

That is exactly what a broken blend door would do, moreso on low-speed fan. Go check the video for heater-treater. Use google or youtube. Or look through threads for broken blend door. The female splines between the actuator and the blend door are probably broken.

 

Just an update to this thread if anyone is following it. I put a new post up about the solution to my heat problem which was caused by a factory, in-line, flow restrictor in the supply heater hose.

 

How do I find your new post? Sorry, New here but having same problems. Thank you.