Don't Shut The Door!

I have an issue, my 2003 Ford F150 (4.6, automatic) locks the doors sitting still. You don’t dare leave it running and shut the door cause, it will lock. Happened twice. On top of that, when I use the cruise control, it will work just fine then all-of-a-sudden kick out, then won’t come back on for awhile. When it does this the transmission will shift in and out of overdrive. Now saying this the trans. will also do this without using the cruise. It soes not do it all the time just once in awhile. No check engine lights coming on and have already checked the main body ground. Please help me with this problem, I have 100,900 miles on the truck and this is absolutely the first problem I have had in the past seven years.

Also someone did tell me that there may be a sensor to the rear axle or on the axle that that sends a signal that the vehicle is moving. The truck does have those automatic locks that lock when moving. Could this be the problem?

Read the owner’s manual. There is a procedure to turn off the automatic door lock function. I found it in my manual for my 2000 Ford Explorer, but my wife won’t let me use it. As far as tracking down the cause, I doubt a rear axle sensor is doing it. I think it is a function through the body control module and it’s interactions with the ECM and TCM.

Also, does your ‘OD OFF’ light come on or flash? This is the signal that the TCM is sensing problems with the transmission. I’d definitely use a reputable transmission shop, not the dealer (they farm out transmission work and charge you extra for it), and not a chain. Figure out the transmission issue first before it becomes expensive. When the transmission is acting up like this, it is causing undue wear and tear, and can damage the unit. Fixing this will fix the cruise control and may just fix the locks.

Thanks in advance. No the OD off does not flash. See what gots me is that I can drive the truck weeks without any problems, then sometimes I hit a bump or pothole and it will make the tranny shift out of overdrive. I can be cruising at 70 for hours and then it will start shifting up and down, then be just fine for for another 500 miles. Not sure, but will look into what you have replied. Thanks again.