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tail lights will turn on and off by themselves with or without key
So first its a 2008 Ford F-150 w/ 5.4 liter triton engine. it does have an auto start.
for the last few months here my bosses ford f150 has had an issue where his tail lights will turn themselves on (for up to 12 hours, or until disconnection of battery) or until they randomly decide to turn themselves off.
this can happen while the vehicle is being driven but more often happens without anyone or the key in the vehicle. so he usually woke up to a dead battery.
as of recently he purchased a battery tender that he mounted into the engine bay so he can start his vehicle every morning.
we have checked/pulled all fuses and relays we can thing to and also multiple fuses and relays in a variety of combinations but none seem to cancel out the constant signal to show as though he is in the truck holding the brake pedal to the floor.
any and all help would be appreciated
for the last few months here my bosses ford f150 has had an issue where his tail lights will turn themselves on (for up to 12 hours, or until disconnection of battery) or until they randomly decide to turn themselves off.
this can happen while the vehicle is being driven but more often happens without anyone or the key in the vehicle. so he usually woke up to a dead battery.
as of recently he purchased a battery tender that he mounted into the engine bay so he can start his vehicle every morning.
we have checked/pulled all fuses and relays we can thing to and also multiple fuses and relays in a variety of combinations but none seem to cancel out the constant signal to show as though he is in the truck holding the brake pedal to the floor.
any and all help would be appreciated
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The parking lights are controlled by the headlight switch as well as the vehicle security module. Are there any codes being set in any module?
if im not mistaken he said recently he had the trailer power wires redone as the previous one worked loose and drug itself away on the pavement
That's one possibility, a solid routine would make easy work of this no matter where the failure is. Get a schematic so that you can see just what is involved in the circuit, and from there decide the most convenient points where the circuit could be separated for testing so that you can first prove what part of the circuit is the source of the issue and then go about finding exactly where. Remember that the vehicle security module does turn the lamps on, making it accessible would make it easy to disconnect as part of the testing. It is located in the left rear corner of the cab with a supercab, or the "B" pillar in a regular cab.