Last night I drove my '04 expedition xlt about 30 min to pick up the kids, and everything was working great. When I returned to the vehicle 10 min later, and restarted vehicle, I immediately heard a repeated clicking or ticking sound from the area of the 3rd row seats on the passenger side. The noise started before I had adjusted any settings, everything was set the same as when I drove earlier. The noise had a frequency of ~ 1 click per second, and sounded like either a loud electronic relay tripping, or a plastic rotor hittting something.

Upon examination, the noise was coming from the behind the paneling just under the rear window, just where the 3rd row seats are. I removed the top covering junk tray and looked behind the paneling. There appears to be an air intake on the lower moulding, and a fan/compressor? assembly near the top that flows into what appears to be the rear A/C unit (I noticed condensation on the metal piping). This fan unit was clearly the source of the noise.

I noticed an F-150 right next to me in the parking lot, probably within a model year. Since I believe these two are basically the same vehicle, and the pickup doesn't have the same component that is making noise in my SUV, it must be interior/cosmetic/door-related rather than essential to the drivetrain/towing/4wd of the vehicle. It clearly wasn't door or seat related, which left me w/ ventilation. Since I saw the condensation on metal piping, I assumed A/C unit. Does my vehicle have an A/C unit in the rear?

To troubleshoot, I restarted vehicle several times. I tried lowering/raising the rear seats with no effect. I tried turning the rear air fan up, down and to floor mode with no effect. When I reached into and disconnected the electrical connection right on the fan/compressor? at the top - the noise stopped. In the end, I left the unit unplugged and vehicle drove fine, with no warning lights. I haven't had time to pick up a Haynes manual, but will this afternoon.

VEHICLE:
2004 Ford Expedition XLT
4wd, 5.4 V8, power 3rd row seats, towing pkg.

QUESTIONS:
1) Is this probably a fan on a rear A/C unit? Does this SUV have an A/C unit where I described it?
2) Is it fine to drive with that fan device unplugged?
3) Is this a common failure/repair problem that anyone is aware of?
4) Any guesses what this would cost to repair?
5) Is this an easy DIY repair, or does it involve a trip to the dealer?

Thank you very much for any advice.

 

[i]QUESTIONS:
1) Is this probably a fan on a rear A/C unit? Does this SUV have an A/C unit where I described it? Yes
2) Is it fine to drive with that fan device unplugged? Yes
3) Is this a common failure/repair problem that anyone is aware of? Unaware of this problem.
4) Any guesses what this would cost to repair? No it depends if part's are needed.
5) Is this an easy DIY repair, or does it involve a trip to the dealer? Do not know[ul][*] I would see if the fan it self maybe hitting some kind of derbis or paper.[*] It may be the rear compressor circulating freon.[*] If all else fail's and the noise is to much you might want to take it to the dealer.
[/ul]