Hi TTiF'ers,

The customer complaint was at times air from the panel vents would switch up to the defroster vents. This would often times happen when accelerating on an on ramp. Usually one would find a degraded vacuum hose to the HVAC system by the battery that would usually cause this problem.

When I got the vehicle, the air was constantly being diverted to the defroster vents. I removed the EATC control unit, and found that the vacuum source was present, and that all of the vacuum motors operated properly when tested with a vacuum pump. That pretty much left the EATC as the problem.

The consumer balked at the cost of the EATC from Ford $365, and asked if there was a rebuilt unit available. Searching online I found this thread.

http://www.f150online.com/forums/hvac/381170-eatc-rebuildable.html

It seemed straightforward enough, so I followed the procedure, and I took a picture of the disassembled EATC control head.

[2002 Ford F-150 XL, Photo]

The unit works flawlessly. When I started the truck this morning the air was blowing through the panel vents from the get go. All 4 "O" Rings should be replaced. The 4 solenoids share a common vacuum source, and I would think having only one leaking would degrade the performance of the control head.

HTH,

Danny from California

Files Referenced: