Hollabakzach23

Good morning friends!!

So some weird demon has been inside my truck the last few days! Every time I lock the truck with my key fob it will honk to show its locked and not five minutes later the panic alarm will sound. I have to go out and lock it and it will honk five times. I have no idea where to even start with this.

I know the dealer can track it on a computer but I wanted to see if it was something I could do myself before taking it in there.

Some information that may help us all find a solution: I bought the truck about 4 months ago and it came with the dealer installed "alarm" and remote start. They both worked fine when I first got the truck other than me having to adjust the antennae that was under the steering column attached to the ignition cylinder.

Now the remote start function quit working about 2 months ago when my keys were stolen from me while I was at work. I had to call a locksmith and he made two brand new keys for me which erased the coding from the old key I had and disabled the remote start function from my old key fob.

That is about all the information I have that would be relative to this issue! Thanks for taking the time to read this and all help is appreciated!

Mechanik

I don't have an answer, but this may help your research. The remote starters usually have a bypass module that, (surprise!), bypasses the key-related security (PATS- passive anti-theft system?) of the Ford. I'm guessing that your key issues have combined with the remote start module and the bypass module to try to drive you crazy. Imagine the "Transformers" movie while you read that.

18_F-150_XLT_Screw

iTrader: (1)

http://machenry.com/documents/Instal...09_04_2009.pdf

Page 86 starts f150. This is what I used to install mine. It has troubleshooting and how to reprogram the bypass back.

Z7What

My 03 had a similar problem with a aftermarket alarm. The shop had to install a diode on the dome light or something.

Wayne

Hollabakzach23

That would be an interesting place to look.

I've read about the pats module ordeal too and I appreciate the manual. I read through the pages you mentioned thank you! Been super busy working this weekend so haven't had much time to mess with it

homer

Z7what hit it right on the nail (at least I'm very sure - assuming they wired to door pins).


If they installed the alarm to the Door pins which is the best way on our truck as the dome light as a delay on it (otherwise the alarm will think the door is open for an additional 45 seconds or so), you need to diode isolate the door pin lines from the Body Control Module (BCM) to the Door pins.


What happens is the BCM goes into a low power sleep mode and pulsates sending ground signals up the door pin line. The alarm misinterprets this as a door open and triggers the alarm. Back in 2007 when I installed my remote start and alarm into my truck I was mystified by this as well and had to deal with it. You can literally put a meter on the door pin line and watch the line pulse to ground with the door closed after approximately 5 minutes or so. There's actually other posts now relating to this too.


What needs to happen is the door pins (individually) need to have a diode between the BCM and door pin to block the BCM from sending the false ground signals up the line. THEN you need to diode isolate between the doors so you don't have the BCM thinking the drivers door is open when the passenger door is open or vice-versa. Depending how many doors you have will depend on how many diode's you require (they're cheap though). So for 2 door trucks, you need 4 diodes: 2 to block the BCM on each door pin, 2 to isolate the doors at the alarm input. For 4 doors, you need 4 to block each door pin, 4 to block at the alarm input. Nothing fancy, just a 4N1001 diode will do this job with no issues. I really prefer using door pins directly because when that door is open, it's open... no dome light delays, none of that stuff. I want the alarm to know that the door is actually open when it is and closed when it is. We're all different though, some people aren't particular like me lol.

If you need help I can draw you up a diagram. It's not hard to resolve but it's likely the issue you're having if they've tied directly to the door pins (which is still the best way in my opinion).

homer

My paint skills aren't the best at all hahahaha, but here's an idea.

Hollabakzach23

Haha wow! I truly appreciate the explanation which was very easy to understand! I've had no time to look into it and wanted to gather up as much information on the topic i could from threads that werent eight years old etc. but I am off tomorrow night and will look into the door pins.

Where would I go about picking up these diodes?

homer

You're in the US but do you have a radio shack there? You'll pay a bit more for them from a radio shack (not much) but that's probably your quickest option. Otherwise if you have an electronics store they'll have them (not best buy or future shop - they don't deal that level of detail).


http://www.radioshack.com/product/in...erValue=Diodes
http://www.radioshack.com/product/in...erValue=Diodes


You can get away with a 1N4001-7... The only difference really is the peak/reverse voltage which you're at 12V so it won't be an issue.


The only other tricky part is you need to follow the door pin wires now. I tied into mine under the floor panels that flow along the doors... If you're going to add the diodes, that might be your easiest place to do it for each pin. If they tied into the door pins they probably already added the diodes at the point where they join (I hope lol), so you'd be able to get away with pulling up your drivers and passenger floor boards and adding the diodes to isolate the BCM there. You just need to find the correct wire colors.

homer

Also make sure you don't put the diode facing the wrong way. The easiest way to know if you did is, after you split the drivers door and add the diode, if it's backwards when you close and open the door the truck dash won't beep and the door ajar light won't come on (for that particular door - assuming all others are closed). Once you do one door, the rest are pretty easy.