First thanks to all who can help.

A couple of weeks ago I was getting ready to wash the truck when the rear brake lights and the truck bed light just came on. They did it a couple of times over a 15 minute period so I opened up the truck and started it and had no problems.

I told the wife and she thought I was full of it.

Today she came home (I work out of town) and she called me up a bit worried that something was going on as the truck lights were on when she came home. She did started the truck and had no issues so I thought I would post to see if any of you folks know what the problem might be.

We are the original owners and the truck is an 04 FX4 SCREW 45k miles with almost all the options but upgraded stereo.

I did try search but was not successful.

 

ground?

you're pushing the unlock button by accident on the key FOB?

 

do these trucks have brake light switches? i remember when i use to work at O'reilly Auto Parts that would happen to some cars, but i dont know if these trucks have them.

 

The Fob was not an issue, when it happened to me I thought that at first and asked the wife and the keys were untouched. Same tonight when she cam home as the truck keys/Fobs were in the house and we live alone.

I thought about the brake switch (if one exists) because I have seen it happen on two classic mustang that we had, however the brake lights would stay on all the time and not off and on.

Man I hope its not an intermitent ground as vehicle wiring is a PITA

Thanks!

 

you might want to have the battery checked. My grandfather has a Lincoln Towncar that the lights would intermitantly turn on and the alarm would go off. He changed the battery and all has been well since. I believe that if the car detects a low voltage from the battery it kind of sends the computer, and with it the electrical system, into a tisy. Just a thought.

 

check the trailer wiring harness. i know my sister and her boyfriend took my jeep out when I was gone one night, got rear ended by a guy, but didnt tell me about it. they knew how pissed I would be. I never let her drive my cars, and I really wouldnt let one of her boyfriends. I came home, saw my brake lights and reverse lights doin weird things. Then I saw the housing by the harness was smashed. Check those wires, they might be causing something.

 

good suggestion. I parked my Durango, went inside the house and came back out 10 minutes later. Put the key in and the thing went bat**** on me. Alarm going off, relays clicking everywhere, headlights flashing, radio randomly on/off.

turns out the battery had suffered an internal failure. still read 12volts at the terminals, but was just bad. did the same thing to my F-150 when i swapped it to test it out.

 

Well the battery is the original and in southern Nevada the batteries seem to have a shortened life regardless of make/model.* That seems like it would be the cheapest route to start with.* I was hoping someone on the forum may have had a similiar issue as every time I hade a question or problems someone else had seen and provided guidence which is way
Its just weird that the only lights that turned on were the brake and bed floodlight.* Thanks again and if I find out something concrete with the battery I will pass it on.

 

cheap as in being free right? I'd just do a quick swap with another battery

definetely let us know the results

 

All vehicles have a brake light switch somewhere... most have them on the brake pedal. Others have a pressure activated switch on the master cylinder (reference the extensive ford recall)

My first thought was the brake light switch... till he said the cargo light also came on... that is not controlled by the brake light switch.

I'd check for shorts in the wiring if the battery replacement does not work.