No power to rear a/c unit or controls
 

1998 Ford Expedition EB Edition 5.4L 4x4

Hey guys...

Well Im getting a lot closer to getting the Expy ready for her trip to TN thanks to all you fine folks. Spark plugs changed, COPs changed, other misc service stuff etc.

I have a question in regards to the rear AC. I cannot get the unit to function or better yet power on. I have never had a rear AC type vehicle, so not sure if I am trying to turn it on right or not...heck I dont even have an owners manual. I figure it cant be too hard..Ive turned the knobs is all types of combinations but the rear AC doesn't power on.

Any idea where to look? Im guessing the fuse box is a good start...anybody got some pics of its location and what fuses and or possibly relays to start poking around and trying out?

Do you have the front on while you are trying to do this? It needs to be.

Yes sir I do....

I have the front on and start twisting knobs and nothing happens in the rear.

From what I remember about my old expy is that there was a setting on the knob up front that had to be set to rear for the rear controls to work, have you looked at that. Oh, and by the way here's where you can find your owners manual. https://owner.ford.com/servlet/Conte...OwnerGuidePage See page 30 and you'll see what I was referring to.

AWESOME>>>>THANKS A MILLION!!!!!!!

Glad I could help.

Well went and checked the fuses....there was 3 of them if not mistaken (2 minis inside on drivers side ***7/23***and 1 in engine bay ***13***). All checked out good.

It started to rain so calling it off for time being.

Success......

I went back to the rear AC and had the controls turned to the "on" position and was getting nothing. I felt the lines and they were super cold..so I figured, well the blower fan must be dead. I unplugged it, checked the connections for corrosion and there was none. Plugged it back in and for crap and gigs, I gave it a love tap "palm heel strike" and wouldn't you know it...the SOB kicked in and is doing it job again. Gentle persuasion rules again!!!!:D

Well I spoke too soon...rear AC is down again. I know for sure it worked the other day.

I went back with a multi-meter and tried to verify I has power going back there. There is two plugs that I saw (one was 2 wire on what looks to be blower motor and other is 4 wire going into some black box looking thing)

Anywho, I took my multimeter and couldn't get any type of power reading back there. You guys got an idea where I can look? The fuses I mentioned above look good.

Well I dug a bit deeper...looks like the yellow 20 fuse is not getting power per my test light on either side of fuse. I looked up the online user manual another user sent me and it says "power supplied through multi-function switch". Where and what the heck is that? I figure I at least got to get power to that fuse.....would that 20 have anything to do with the rear AC? Sorry Im not too electrical savvvvyy......

Attachment 199446

Oh BTW....I don't have DRL's (I don't think) and my Hi-Beams work fine...as well as instrument cluster

I'm not sure why your looking at fuse #16. I don't think it has anything to do with the HVAC System.

aka the turn signal stalk.

It would be helpful to know for sure if you have the manual climate control system or if you have the EATC (Electronic Automatic Temperature Control) System. And are your rear controls located on the back of the console or up on the roof? (Prolly depends on if you have the sun roof or not.)

I assume your front blower works properly. First check fuse #7 (powers the console blower motor) in the smaller Junction Box under the hood and fuse #13 (powers the auxillary blower motor) in the larger Power Distribution Box under the hood.

Put the front panel function control switch in the "Panel" position.
Put the front auxillary blower switch in the "Rear" position.
Put the *rear* auxillary blower switch in the "High" position.

Does the Auxillary blower motor operate?

Hello again,

I have manual controls...good ole twisty knobs...I was unaware there was anything else out there.

My Expy has the main AC console in the dash, with an overhead control panel for the driver to also adjust if he/she sees fit. Also, there is no control on the floor for the AC for the passengers (vent wise), just stereo stuff, however the 2nd row does have overhead AC controls.

I just checked the fuses under the dash...I had (2) number 5 fuses next to one another so I am picturing both...I apologize but I am dead beat today...hard to think straight much less poke around in the dark ;) Both number 5's light up on the test light.

Hauled taters to under the hood and the big green 30 is lighting up too...

With the instructions you provided...the rear blower is not engaging...no click, thump, pump, bump or poof...she sits dormant.

Attachment 199443


Attachment 199444

Attachment 199445

That helps. :-X22

Oh, okay. NOW I see what you are referring to: Verbage throws me off - I thought you were having trouble with the AC, as in air condictioning. Your having trouble with the HVAC (Heating, Ventilating, and Air Condictioning) controls.

So you have *THREE* HVAC control panels. Main one in the dash, one overhead for the driver to control, and one overhead for the 2nd row to control? Can we get pictures of these, also?

So do you not have a sunroof? And you have power wing vents way in the back?

[quote=DEMIGOD;14003851]I just checked the fuses under the dash...I had (2) number 5 fuses next to
one another so I am picturing bothAttachment 199442


/:-huh
So we will have to determine if the issue is a fuse issue or relay issue.

Hey guys.....

Well here and update. I installed a used power seat track today for the drivers side and decided to dig back in to the "HVAC" issue with the rear system not coming on. To my surprise, I found that if I wiggled the 5A fuse a bit, the rear AC would start blowing through the roof vents. I was like "hmmm" I tested all the fuses last night and got power on both sides of them, so I kind of figured the issue was somewhere else.

However I now have confirmed that when the rear AC isn't blowing I can simply push on and or wiggle that fuse and she starts working as should. I went to two parts stores today and wouldn't you believe it, none of them had a pack of 5A fuses..plenty of combo packs, but didn't want to go that route (I got like 100 misc mini fuses and reg fuses in tool chest).

So, over the next couple days, I will buy some new 5A fuses and install them....heck for all I know those fuses in there (other than the ones I replaced) are 16 years old and may be on the verge of needing replacement.

Thanks again guys!!!!

:-jammin

i have the same program on my 97 expedition, is their a rely for that unit and where isit