connecting alarm to factory fob

Hi, While I have a genral idea of how things work, I am what most of you will refer to as a newbie, please bare with me. Any ideas will be appreciated. I've racked my brain on this one for two days now. To begin with, I have an 2005 Ford f150, after melting two JL Audio 10w3's and blowing my Eclipse head unit, I am forced to do a reinstall, and while I'm at it I decided upgrade a few things. For the last five years I've been walking around with two fob's on my key chain, one for my truck, the other for my alarm. I like the features that came factory, i.e. approach lights, progressive door locks, and a few others, I also didn't want to get into waking up the GEM module. so to keep these features i believe I have come up with a plan. I intend to take one of my factory fobs, replace the push switches with relays, add a power supply for the fob, and have the alarm lock/unlock fire the factory fob. Now here's my problem, my alarm is a Viper 350hx, it has three wires coming of the harness for the door locks, one wire is not used, the other two wires are dual purposed, (+ lock - unlock) and (-lock + unlock), how do you wire these wires to get the relays to fire the fob relays. I know it might sound silly to ask this, but I had thought about hooking the line to 85 of a relay and 86 to ground, the idea was that when the line fired positive it would trigger the relay, when it would fire negative nothing would happen as it would be a negative to negative connection, was I off in my thinking, thanking everyone in advance, Scott

Not sure what your budget is, but they make alarms that work off the factory remotes. Automate AM1, Audiovox PRO-9233 are common examples.

Thank you for reply, since I paid $200 plus for the alarm and senors back when I bought the alarm and there is nothing wrong with it, I don't really want to replace it. I look at it like like there is always a way to make it do what you want it to do, you just have to massage it a little. I'm just looking for the easy solution. I think my plan keeps me from having to wire a circuit each individual function I want my system to preform. Please remember I'm a rookie when it comes to creating circuitry, please tell me if I'm understanding this correctly. if I use diodes, I would wire the diode positive side to the alarm wire, negative side to the alarm fob. the result would be when the alarm sends a negative pulse to the fob, current would be allowed to pass grounding the circuit, and when the alarm sends a positive pulse, due to the resistance of the diode the pulse would not be allowed to pass and the charge would dissipate. do I need any form of protection for the circuit other than the obvious. and if you had wiring diagram of any sort, that would be a huge help. thanks again, your help is always appreciated. Scott

I feel sure that the simple answer to the original post would have been to install an alarm with a remote that would have taken over from the factory fob.

Gentlemen, let me start by thanking those of you who have offered assistance. I believe that the solution to my problem is as simple as follows, because the factory fob has two push switches that I need to operate, both of which in turn complete two seprate circuts., a DPDT relay will be used to make the connection for the two switches, diodes will be wired to the relays for protection. I will connect one side of the coil to ground and the other to the respective wires. the relay should only trigger when it receives a positive pulse. as far as the power supply for the fob, that should be no problem as I'm sure I have something in my spares box that will work. for those of you that can offer nothing more than an opinion, while I respect that opinion, you have to realize that your really no help at all. yes, I understand that buying a new alarm with all the features I want is possible, but I have a decent working Viper alarm that with a little work will do exactly what I want it to do for about ten dollars, verses one hundred and eighty dollars for modules to do the same thing, all with a lot less wiring and headaches. I have always been told, solution or problem, you can only be part of one, so which one is it going to be?. that in my humble opinion is what is wrong with most forums around today, to many opinions. but thank you for your time. if you really want to scratch your head, I'm thinking about dual proximity sensors on the same truck, one dual zone for the cab, and an instant for the bed, yes I know about the false triggers possible, but maybe a moisture sensor to disable the proximity sensors when it rains will eliminate that. how about a prepaid cell phone to allow me to disable the throttle on the truck in case of theft or carjacking, and a lot further away than fifteen hundred feet offered on most alarms, maybe even connected to call my phone six states away when the alarm triggers. its all possible, yes I'm sure someone thought of it and I can buy an alarm that can do it, but really, you have to admit that it's a lot more fun to figure it out yourself, and doing it yourself gives you a feeling of satisfaction that no one can take away from you. thank you all again, especially the ones of you that actually helped. Scott

Oh and just a thought, reasons things can't be done,cost to much,wife will kill me,might kill my wife,prison time is possible,prison time is a definite,too damn lazy,too damn hot,the man is keeping me down,parts on back order,I'm outta dollars and she won't take an IOU,24 is on,the game/race/24 is on,it might hurt,it's going to hurt,Attention Deficit Disorder, i.e. "if I take part a and connect it to Oh look a duck!", other than these, a few more I'm sure someone else can come up with, there is no reason why with a little imagination and trial and error, you should not be able to accomplish anything you put your mind too.