lt-Did you run it on heat after you clamped the hose until there was no more heat (get rid of all the heat in the heater core once the hose was clamped)? Then try your air (hose still clamped) while driving? IF you did those things, you have to borrow or buy a set of gauges to check the pressure. If the pressures are ok, I still say it's in the doors. With the 93 degrees that you reported with the air on there is no way the compressor can be functioning normally and the pressures correct and HEAT not getting into the ducting that should be producing COLD air. That vehicle is definitely capable of it!

 

lt- I would say the temp's you've listed are pretty accurate (40 to 46) That thing should freeze you out, especially at 76 F outside. You have dual air if you have rear controls and therefore also have dual heat. Make certain there is NO circulation through the heater hose system. And that the heat that was in the heater is all drawn off.

 

Code,

Maybe I clamped the wrong hose. Which hose is the one I need to clamp?

 

I'm not sure either one is the heater hose, but they looked the right size. However, I'm not used to a heater hose having a crimped connector. My heater hose on my 2005 F-150 Regular Cab has a typical hose clamp. However, if those hoses are hot (meaning they are the same temp as your big fat radiator hose going to the radiator) then it may indeed be the heater hose. I'm not sure what the tee connector is for in your picture unless maybe you have rear heat & A/C controls. If, in fact, you successfully clamped the correct hose and your vent temps do not read about ~43 deg then you have other issues. If your vehicle has rear A/C then most likely you have a T-valve that is sticking and need replacement or perhaps you have condensables in the system and need a complete flush and evac.

I think you have done all you can do without the proper equipment.

 

lt- I think that probably is the heater hose, they do use crimped clamps an dual systems. From what I can tell I would first check as the other poster said, and from the temp of the hose once the vehicle is warmed up, if that is it, clamp it off on the lower leg of the tee. That way your shutting it off to both front and back. Follow my earlier directions and make sure the fan is run on heat until no more heat comes out once it's been clamped off. Then go for a ride and see what the air is doing and you'll know where you have to go from there. Good luck and keep us informed.
P.S. I don't know where the heater hose comes off the block with the hot water but I would clamp it close to the block if you can and then there is no question. Make sure it's the outgoing hose and not the return hose.

 

I have had pretty much the same problem the last couple of weeks. The AC blows somewhat colder than the outside air - but not much. I went and got a freezer thermometer and was surprised to see 90 degree temps - with max air.

I took it to the dealer - they replaced the accumulator (thanks to this forum I had them check the blend door). The replacement worked GREAT that night... next morning on my way to work - zip. I should add the accumulater was $150 but putting it in was $250.

I took it back - they said it was 40 degrees and fine. The next day I drove it straight to the dealership from work at lunchtime. It was blowing 80 when I pulled in the service bay... damn - an intermittent problem. They checked the blend door again - just to please me - then spent two days with it. They finally decided it was a leak in the orifice hose. I just picked it up at lunch today - it is colder... but not the winter forest I used to have.

BTW - I'm in North Florida where it regularly touches 100 degrees. AC is not an option down here. I think it's fixed. Fingers are crossed and orifice is covered.

 

Do you mind putting a thermometer to yours to see what temp you are getting now that its fixed? If I could get mine down to 40 degrees that would be super!

Code: When I get the heater hose clamped properly, will no air come out of the vents on heat or will just be air blowing at the outside temperature?

 

It will just be air blowing at outside temp, the blower will work just the same, just not heat to pull off of the heater core once the heat is drained off of the hot water that was in there. Running it (the blower) till the air coming out is room temp. is a must.

 

the Max AC does two things - first, it blocks outside air and recirculates interior air. Second, there is a vacuum operated switch on the heater hose line that closes off the flow of hot water via the vac valve when Max setting is selected. You can see it on the heater hose in the engine bay, just in front of the firewall. Have someone turn to Max while you watch. You will see it move. Make sure it does. If it isn't, you may have hot water in there all the time.

 

UPDATE....

Still cant locate the heater hose.....

I clamped what I thought was the heater hose but there was no changed in temp on heat.

Does anybody have an HVAC schematic for a 99' Expedition?

This is getting ridiculous.

 

Since your vehicle is getting up in years I strongly recommend the following:

http://www.alldatadiy.com/

It provides electrical, mechanical, cooling, computer codes and much more. At $24.95 it is quite a bargain. With this account you will be able to locate the heater hoses with just a few clicks. BTW, this is what many ASE mechanics use.

 

Kinda dissapointed in the schematic on Alldata.

Which one is the heater hose that I need to clamp?



Item Description
1 Green tape
2 Front auxiliary heater inlet line
3 Blue tape
4 Front auxiliary heater inlet line
5 White tape (bracket locations)
6 Orange tape
7 Front auxiliary heater inlet line
8 Rear auxiliary heater inlet line
9 Rear auxiliary evaporator outlet line
10 Rear auxiliary beater inlet line
11 Violet tape
12 Rear auxiliary evaporator outlet line
13 Front auxiliary heater outlet line
14 Red tape
15 Rear auxiliary heater inlet line
16 Rear auxiliary heater outlet line
17 Rear auxiliary evaporator outlet line
18 Rear auxiliary evaporator inlet line
19 Yellow tape
20 Rear auxiliary evaporator inlet line
21 Rear auxiliary evaporator outlet line
22 Rear auxiliary evaporator outlet line
23 Rear auxiliary evaporator inlet line
24 Rear auxiliary evaporator inlet line
25 Rear auxiliary heater outlet line
26 Rear auxiliary heater inlet line
27 Rear auxiliary heater inlet line
28 Rear auxiliary heater outlet line
29 Front auxiliary heater outlet line
30 Front auxiliary heater outlet line

The auxiliary lines are two-piece tubes that are secured to the underbody of the vehicle. New auxiliary line kits are only available with multiple-piece lines for ease of installation.

 

lt- it looks to me like those are all under the floor of the car. You need to stay up under the hood of the car. It shouldn't be to hard to tell where the hot water exits the engine on it's way to heat the interior of the car. Clamp it before it Y's off to the front heater core and the rear heater core. As the one poster said, check to make sure the water flow control valve is working. I have a '04- new body so it's completely different than yours, and has no shut-off from what I understand. It only uses the blend door to control how much heat gets in. I have an '00 F-150 Chilton manual so it should be similar to what you have in the Expy. I'll check it tomorrow.

 

You may need to view a few more diagrams to get the right one. Another good technique is to view a diagram and then locate the parts on the car itself. Below are the ALLDATA diagrams for my F-150 that show where the hoses protrude through the firewall. See if you can find something simliar for your vehicle.

 

Bugman- His is probably going to look a little different than the one illustration because his is dual and that illustration is for single- but your heading him in the right direction. I did look in the '00 Chilton manual that I have and it is totally worthless! I have factory DVD's for '04-up but nothing for back from there. We'll keep trying. I still think it's in blend door or blend door actuator, possibly the valve which my truck doesn't have. At any rate, heat is getting into the system from the heater when it shouldn't.