Question about 1999 Ford Expedition

2 Answers

1999 expedition 5.4 cold air from dash vents, hot air from rear vents with a/c on max and all fans wide open. any thoughts?

Posted by on

  • 4 more comments 
  • ian brenner Apr 23, 2010

    thanks pal. just charged the system and moments ago verified system operating pressures, so i will rule out answer two at this time.

    the mix door idea is intriguing... there must be separate mix doors front and rear? is that possible?

  • ian brenner Apr 23, 2010

    i'm having trouble visualizing a problem with the mix door. if there is only one mix door, why would i get 44 degrees temp from one vent and ambient temp from another?

    are there more mix doors on this vehicle?

  • ian brenner Apr 23, 2010

    where is the rear evaporator located?

  • ian brenner Apr 23, 2010

    thanks, i will look. i appreciate your time and effort!

  • ian brenner Apr 25, 2010

    ok, one more time... please answer only if you are an expert.

    the system operates with 2 evaporators; front and rear. front blows cold, rear does not.

    system operating pressures are normal; both high and low pressure sides.

  • ian brenner Apr 30, 2010

    dj_relly is on the ball; DARKLORD1 IS CLUELESS!



2 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Expert
  • 4,070 Answers

Hi! If all the thermostat are set correctly then I suspect the rear evaporator coil. This may be dirty and requires cleaning. Once cleaned I believe that cool air will be blowing, thats for sure not unless the evaporator has a leak. Hope this helps and have a good one!

Posted on Apr 23, 2010

  • dj_relly999
    dj_relly999 Apr 23, 2010

    Hi! Try looking at the rear, a black box could be on cover.


  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Master
  • 2,427 Answers

It seems the air is possibly getting warmed up before it can reach the back vents,, or it could be the air isnt getting cold enough or that the ac / heater door for the back is stuck..

1.) you will need to trace the vent unit back to the blower below the dash,, you will notice its like 1 long tube that every things runs from.. The one to the back is connected to this tube,, enuse it is so and securly.. on the tube is a vent door, make sure its moving,, check your temp and controll settings on the ac control unit and make sure its working..

2.) Check your ac freon (gas) make sure you unit isnt leaking or needs regasing .. this causes this as well.

Posted on Apr 23, 2010

  • Rishi Roshan Ali Apr 23, 2010

    the unit use 3 seperate hoses ,, 1 for the front,, one to send to the back and another for the back.. They just fit into one another without any fasteners,, chances are oon of them just slipped out,, and yes there 2 mix doors,, not so much for cooling but more so for heating!!

  • Rishi Roshan Ali Apr 26, 2010

    then the rear evaporator isnt working.. the evaporator is what colds the air.. The unit doesnt have a shared colding system but two individaul ones controlled by the same unit.. chect the rear evaporator to see if its getting power,, you can do this with a multi meter on the contact wires (where the wires connect) ,, once its getting power it means that something is wrong with the evaporator.. if it isnt getting power ,, the rear evaporator has a seperate fuse.. the fuse is located under the hood in the fuse box,, under the fuse box cover is a diagram showing where each fuse is and what it controls..



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

2003 ford expedition i just got it a week ago and the front heat works great but the back vents only blow cold air. How do i fix this?

With the car parked and engine idling, turn the ventilation control between windshield defroster and "open air ducts" to front and rear vents. Listen to pinpoint where the valves are that open and closes the air ducts. It sounds like the air duct to rear vents are blocked, and the cold air in rear air duct is coming from "outside ventilation." The air vent to allow hot air to the rear vent is stuck in "open ventilation" mode, like when you're driving in spring or summer months.

Nov 29, 2013 | Cars & Trucks

1 Answer

1999 ford expedition I am getting almost no heat in front or back. I have flushed out heatercore. I have change thermostat. When the engine is at 2.5 to 3,000 RPMs I get heat. No heat when it is idling....

Try the heater controles.There is a possibilaty with this expedition that the heater doors are not opening properly.When motor is at low RPM the vacum the motor pulls is low to.This vacum is what controls the doors and vent.You can pull vacum lines on and off ONE at a time and listen for the doors to open.There is also a good possibilaty the vent door contol switch at the dash could be bad.You would need a vacum gauge to test it though.

Dec 15, 2010 | 1999 Ford Expedition

1 Answer

Fan motor does not blow hot or cold air when turned on

your fan motor is located on firewall behind engine towards middle of car under a cover gain acess turn fan on inside car lightly tap back of motor if fan starts running you have a bad fan motor i assume you have already checked your fuses

Mar 16, 2010 | 1999 Cadillac Eldorado

1 Answer

My 99 Eddie Bauer Expedition blows cold air when

the heater is a long plastic box and the mixer door is inside of the box. The stepping motor controls the door.

Apr 15, 2017 | 1999 Ford Expedition

1 Answer

This car has the automatic temperature control system

The hot/cold switch is probably have a blend door box that opens to let the cold air in and closes to let the hot air in.From what you are saying this part is no responding to the switch movement.Make sure power is at the switch and power should go through the switch when put on cold air this moves the blend door.Some times the blend door goes bad and has to be replaced its under the dash on the right side.

Aug 10, 2009 | 1999 Mercury Grand Marquis

3 Answers

2004 Ford Expedition XLT, front blend door actuator

Hope I was avle to help, glad you up and going.

May 26, 2009 | 2004 Ford Expedition

1 Answer

Temperature Control not working on 1999 Ford Explorer

Sounds like your temperature actuator is not moving or your temp door is broken. On max a-c ,coolant is shut off to your heater core allowing only cold air in.

Jan 16, 2009 | 1999 Ford Explorer

2 Answers

2002 Lincoln Navigator. Heater is not working, it blows cold air. I had the thermostat changed and it stills blows cold air. There is no water leaks under the dashboard. It takes about 10-15 min for...

try changing the thermostat if thats not it check and see if you have water leaking in the passenger side floor board if so then you need a new heater core

Jan 05, 2009 | 1999 Lincoln Navigator

1 Answer

A/c problem

You either have a bad control, or motor running the air direction door in the front HVAC unit, or a door that is stuck.

The front and rear units are totally separate.

The door directs where the air, cold or hot, should come out, whether it is panel vents, floor, defrost, or any combination of those.

This door and motor are located inside the heater box which usually requires a lot of the vehicle dash assembly to be taken apart to get to these parts.

Aug 28, 2008 | 2000 Ford Expedition

Not finding what you are looking for?
1999 Ford Expedition Logo

Related Topics:

115 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ford Experts


Level 3 Expert

79865 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

5687 Answers

Are you a Ford Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides