Where are the alarm sensors for 2002 F150? Every so often the horn has a short beep and the interior, bed & parking lights flash when no key is in no one touching the truck? How do I stop this since the theft alarm can't be de-activated?


Asked by Jul 28, 2015 at 03:09 PM about the 2002 Ford F-150 XLT 4WD SB

Question type: Maintenance & Repair

Horn sounds short beep, interior, bed and parking lights flash on then off, usually about
once and hour at night.  I pulled the horn relay so I can't tell if it happens during the day.  
Ford garage said it is connected to the theft alarm and one of several sensors is causing
it.  How can I trace this out and correct it since the alarm can't be de-activated?

3 Answers


You will need a shop manual with a good set of wiring diagrams in it, then you are going to have to manually test each circuit and the switches to find the right one causing the alarm to trigger on it's own. Not going to be a quick fix unless you get lucky. If you are going to attempt this I would test the drivers side first as it tends to get more wear than the other door switches.

1 out of 1 people think this is helpful.

Thanks for your answer. Are there any free shop manuals or wiring diagrams anywhere on line?


When you get right down to it you will be lucky if you can find anything online at all, you best bet is to check out your local library and see if they have a repair manual in the reference section. There are places that you can buy and download a manual but it is not cheap, and of course there is EBay.

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