As soon as the key gets turned on I get a pretty loud clicking under the dash of our 2004 Expedition. Turn the truck and any heat or ac off and it stops. As soon as the heat or ac is turned on...click, click, click.
Guess a blend door motor or something similar.
Sounds like it is pretty high up towards the topside of the dash.
Any way to determine exactly what is needed?
Guessing that there must be something that switches hot/cold and another defrost/vents/feet.
Wondering which one and how big of a job etc...

I also looked at a 2002 Explorer the other day thinking about buying and it did same.
Similar fixes?

THANKS ahead of time !!!

 

This is one way:

HeaterTreater

Video section will illustrate the repair for you.

 

This is a '07 but it's similar for the '04.

 

Hard to get much better reply than that!
Thanks
I will have to determine which actuator is the trouble maker than.

 

I'm sure it is precisely that.

 

I only looked at it quick last night.
Seemed like no matter where I selected for floor/defrost/vent
or what I set the temp at, hot/cold, AC on or off.
It kept clicking as soon as I turned anything on.
I could turn the truck off with everything set to off and it would not start clicking until I turned heat or ac on.
Then click away until key off again.
Not sure if that indicates anything or not.
I will plan on getting a blend actuator then before I tear into it and just get another one if it turns out differently.
THANKS for all the help ! ! !

Any OBDII / ELM327 gurus here?
I got issues with a couple of my adapters too
None connect to vehicle ecus...
just in case anyone has tips or tricks for those too.
I posted my issues with those in another section this morning too.

Appreciate the HVAC help ! AWESOME !!

 

The chinese ones are a bit hit and miss, and I've seen in some forums that some of these chinese ones are lacking specific safety circuits and can cause damage to the ECU. I have no idea how real that risk of damage is, but I bought this one and it works really well. High quality and fast reading speed.

OBDLink? MX Bluetooth | OBDLink? ? OBD Solutions

 

Those look to be a bit nicer than the ones I have.
Each was about $8 Ebay and Amazon.
Hope there hasn't been anything wrecked on the ECUs.
I don't think so at this point.
Took me a minute to find the price and ordering info for the MX scanner.
$100 is more than the $8 I have spent on each of these, but if they work that would be LOTS better than what I have now.
THANKS

 

Yeah, it does cost more than the cheap China clones, the bonus is that they're properly designed with all safety circuits inside, they have a superior processing chip inside which enables faster polling on the datalink, and it supports the Ford MS CAN network. FORScan can access the MS CAN bus with the OBDLink MX adapter. It's available for Windows and iPhones, soon coming for Android:

What's new

 

You might want to just unplug it first to confirm the blend door motor is the problem.

 

Thanks for everyone's help and advice.
Getting closer to fixing both my issues.
1st, tore the dash and radio out of the Expedition.
Turned the key on and switched heat/AC one.
Dialing from hot to cold or vise versa got the clicking going.
Did not remove or replace the actuator yet, but was able to put my hand on it and tell that was the issue.
Had to run daughter to lacrosse practice so buttoned everything up quick like.
Going to p/u an actuator and hope the door is not bound up.

2nd, somehow someway, my ELM327 scanner decided to link to the Fusion's ECU.
Was able to read and clear my low temp code.
I could also watch the phone readout and saw what seem to be OK temps.
Grabbed my infrared laser thermometer and will try to verify what gage, reading on the phone app, and ecu show. Wondering if only one temp sender for both gage and ecu, or 2 separate...at least I can start trying to figure out if I need a thermostat or sending unit, or wiring issue I guess could be possible too.

BUT, thanks for all the HELP(S) !!!!

 

No problem, try FORScan if you didn't already, it's really great! Specially from a Windows computer, it gives you an awesome tool to troubleshoot the system

FORScan

Oh, and if you have an Android phone, they will release an Android version soon. It's in its final beta testing stage, you can download it from the forum if you don't want to wait. It works for me, but of course, it's beta so you're on your own with that.

 

Was not aware of the FORscan.
Guessing that you get a OBDII to usb cable and hook to laptop with that program then?
All I have done so far is Bluetooth to my phone.

 

If the laptop is bluetooth capable, you can use your bluetooth OBD adapter with it. The cheap china clones require a small modification to access the MS CAN network, there are instructions in the forum there. The OBDLink MX at 100 bucks which you saw a couple posts up can do it all out of the box.

 

Thanks for that too.
Never looked at my laptop to see if it is Bluetooth capable or not honestly.
I will have to check when I get home this evening.