exactly. the module is mounted under the truck behind a metal shield and it corrodes like a MFer. when the mech showed me mine I was fecking baffled by it. why would you not mount something like that INSIDE or at the very least at a high point in the engine compartment like the other ECM's in there. bad design.
Ford does a lot of odd shit. Example, my 01 F150. The fecking cruise control had me baffled. There is a cruise control stop valve and speed control module on the front of the master cylinder. It was prone to failure, and leaked by, causing the ECM to think the brake pedal was depressed, thus not allowing the cruise to turn on. I put in a brand new one ($19, and five minutes). Nothing. I dig a little deeper into the Ford forums, and discover a recall on that part. I go to the junkyard, and can’t find a recall replacement tagged one in a truck, but I find one in an Expedition for $5.
Nothing. I go to the Library, and borrow the fecking Chilton’s Shop Service Manual. I’ve done everything the service manual says to do.
I go back to the Ford forums, and do another search for cruise control, and on page 18, I find a post about the high stop brake light behind the cab. Turns out, it’s also a cruise control stop. If the bulb burns out, the ECM thinks the brake pedal is depressed and won’t turn on the cruise. Sure enough mine was burned out. Replaced the bulb, and bingo, bango, Bob’s your uncle, cruise control works.
Thwarted by a fecking $2 lightbulb.