Installing rear HVAC on a '99

[spt87a]

Hi,

Just replaced my '99 Expedition Eddie Bauer with 285,000 miles and a lot of kid wear and tear with a '99 Bauer with 60,000 that is about as close to new condition as you will find in 2015.

This "new" one has a slightly different mix of options including a moonroof and lacks the rear, aux. HVAC unit. It does have the small unit on the back of the center console that acts like a booster to blow HVAC from the main, front unit into the 2nd row.

I really liked having the rear aux. unit. Anyone attempted to install that on a vehicle that was lacking it? Generally I know there will be lines for coolant and refrigerant to install with a valve on the A/C to tie it in and a change of fittings to attach the coolant lines. Also the wiring to deal with and controls to add.

What about duct work up in the head liner? Is the head liner with the aux unit any different or does the aux unit just direct air up in the gap between the headliner and roof and then holes are cut to install the diffusers? My old Exp. doesn't have the moonroof so the headliner is different to start with so I can't tell 100% although it appears to have some channels molded into it to for the airflow. Also on fordparts.com they don't seem to list different headliners for rear HVAC vs. no rear HVAC. I've considered just adding it but only having using floor vent to avoid tangling with the ceiling.

How about the compressor, condenser and other A/C components under the hood. Is any of this larger in capacity from the factory when the aux. unit is installed?

As I've dug into this I've just gotten interested as an engineering exercise as much as taking on the project - so any info would be great.

 

[stamp11127]

You may consider heading to a junkyard that has an EB with the rear ac so that you have access to a donor vehicle before tearing into yours.

 

[spt87a]

Update

Actually, I do have a donor - the old '99 - so I need to do some more cross comparison. A big stumbling block is the interior colors are different plus the new one has a moonroof/old one does not. So I can't just swap interior pieces - I'll need second donor with matching colors/moonroof config.

What I have learned so far is that there is a different headliner used with the aux. HVAC unit that has channels for the air flow and the air diffusers. Also, on mine there are no ceiling lights for the second row but that seems to come on the headliners that include the rear aux HVAC.

The drivers side, rear interior panel is also different as it has slots cut for the rear HVAC floor outlet. The center console is different as it has the front controls for the rear HVAC molded into front of the storage bin.

I'll post updates for posterity here as I dig into this further - if anyone else comes across any info that would be great.

 

[Mediamonkey11]

I'm confused what the difference is. Can you post pictures? It sounds as though you're trying to install a whole system into the new one, which seems rather ambitious as they are pretty integrated. To be honest I wasn't aware they came with anything else other than full rear system separately controlled! I know I have a sunroof as well but have the controls mounted in a different spot, as do the rear passengers have a separate control to turn on and adjust their airflow that I can lock out or override via my front mounted rear HVAC control that's mounted just below the radio...

 

[Canadian Expy]

UGH I have rear air and a A/C leak so I wish I didn't have it. Miles of lines to check for the leak plus a ridiculous amount of gas.

Good Luck

 

[mike460]

Actually, I do have a donor - the old '99 - so I need to do some more cross comparison. A big stumbling block is the interior colors are different plus the new one has a moonroof/old one does not. So I can't just swap interior pieces - I'll need second donor with matching colors/moonroof config.

What I have learned so far is that there is a different headliner used with the aux. HVAC unit that has channels for the air flow and the air diffusers. Also, on mine there are no ceiling lights for the second row but that seems to come on the headliners that include the rear aux HVAC.

You could remove both headliners, and use the moonroof headliner as a template to cut the moonroof hole in the rear hvac headline, then recover the rear hvac headliner - the material for that isn't terribly pricey IIRC. I would imagine that the bracketry for the rear hvac controls would already exist, or be removable from the rear hvac truck.

The drivers side, rear interior panel is also different as it has slots cut for the rear HVAC floor outlet. The center console is different as it has the front controls for the rear HVAC molded into front of the storage bin.

You could use your rear hvac interior panel and potentially dye it with SEM interior paint (just clean it really really really well, and then clean it again). It would also probably benefit you to get an assembly manual, a Haynes manual, or something similar. At any rate, best of luck!