Door Locks stop working when hot

[David Schmidt]

I've had a consistent problem for several years on my 2003 Sport Trac. As soon as summer hits (I live in Florida) and the truck gets physically hot just sitting in the parking lot like from 12:00 - 3:00 the automatic door locks don't work. The door key pad works and the key in the lock works but the automatic key fob doesn't.



So going to work ok...going to lunch does not work and than go home at night works fine again. Happens EVERY summer when its hotter than usual. What would cause this? Anyone else experience this?

 

[Jenn D]

It's not very helpful, I know, but I had the same problem when I owned my 2003 ST. I too live in Florida (Orlando). I never figured it out, so I'm kind of curious what others say.

 

[Bob McDonald]

My first thought is that there is a connection failure (when hot) where the RF antenna connects to the receiver circuit of the door lock module. Unfortunately, I have no clue where that physically is on the Trac. I have never experienced that problem myself.

 

[Richard L]

David,

Do you hear anything happening at any door when you hit the "Lock" or "Unlock" button when the vehicle is hot? If you hear a noise it would indicate that you probably have a good electrical connection but the solenoids are not activating. That would be odd for all the solenoids to fail at once? If you don't hear anything, it is not likely the solenoids, and probably a fault of the electronic door lock module.



Another test would be to unlock the vehicle with the key and test the "Lock/UnLock" buttons on the drivers door. If the button works, then you wiring and lock solenoids are working fine, which means it is in the electronic door lock module. The heat may be throwing off the electronics and it is either not getting the radio signal from the remote, or is just failing to function when hot.



I don't know how much the electronic door lock module cost, but it should not be to hard to replace...It's located under the dashboard. I'm sure someone here who has a repair manual/DVD can post a photo to help you identify the module. They may even be able to provide a more positive test procedure.



...Rich

 

[Tommy Masters]

With the module being under the dash I wonder if one of the sun shields that goes in the windshield would help. Seems like the dash would get really hot sitting in the sun, and that module word just bake.

 

[Tommy Masters]

With the module being under the dash I wonder if one of the sun shields that goes in the windshield would help. Seems like the dash would get really hot sitting in the sun, and that module would just bake.

 

[David Schmidt]

yeah..its weird. Only during the summer and only in afternoons. Very annoying. When you hit the key fob - no sounds - no nothing - its as if the key fob has no battery in it but than it works again later when it cools down a bit. I'm in Tampa, FL.



The door keypad works fine and if I jump in the truck and turn the ignition or start the vehicle it "does" work typically.



I wonder if I can find that module and wrap some heat guard material around it or something.

 

[Kevin Palmer]

Is the keypad on your door the wired or wireless type?



This would help to isolate the issue.

 

[Dre L]

Old thread, I know, but has anyone made progress on this issue? I'm in Orlando now and it's the most annoying thing. Basically there's little range all the time but it works within a few feet if the trac is cool. When it's been in the sun, the fob never works, and as it cools down I begin to get some range, especially if I'm using the remote under the steering wheel.



I've chalked it up to thermal expansion, and possibly needing a little solder, but I just don't know where to start fixing such a thing.