Hey I recently had Best Buy install my 791XV alarm with remote start; however, sometimes, when I remote start my car, it trips off the stock alarm. The stock alarm is still fully functional, but I don't know whats the problem because it trips off VERY inconsistently. I'm thinking about completely disabling my stock alarm, but the trunk function would be lost and I dont want to pay an extra 40 bux to install the module to hook it up to the new remote. Thanks for your help guys,

3zeroCL

 

Which best buy did you have it done at? Mine did the same thing. You need to go back and have them hook up the wire from the viper to the fac. alarm that is defeat but don't disarm. After they did that and everything worked fine, even the trunk. However the new problem is the starter pulse length is sometimes not long enough. If the car is cold the engine will not catch but it will when it's warm. An optima did not even fix that, so i think you can increase the starter pulse length, so i will figure that out today.

 

i had it done down in so cal at Best Buy in Irvine. Wow, that's an interesting problem. Have you checked your alternator? Do you think the change in wiring caused the short pulse?

 

No the pulse length is still the fac. setting. It only needs to be 1 second longer. Then i think it would catch everytime.

 

I have the same alarm installed. However I have a manual. I had to have a friend of a friend install it due to liability reasons. My remote will not pop my trunk. The guy told me that he would have to tap into my cars computer. Is this true? It still works on my factory remote. I've been to a shop that installs these alarms on cars with automatic transmissons and he says he could fix me up for 50 bucks. Is this something simple I could do myself. Sorry to whore on this thread....

 

JoeLogic - have you checked your fuel rail or fuel pump or gas level? Dang, i hope you get it fixed. I have no idea what's going on. How does your trunk work? Off the old remote?

CL2.3-Amature - the installer at best buy told me that he would have to charge me 35 bux for a module to install the AUX to my trunk on the new remote and completely disconnect my old alarm which would render it useless (to fix the the alarm going off). Have you had my problem by any chance? Oh and I dont think the computer has anything to do with the trunk. Also the trunk will not open from the remote when the engine is on.

 

I have had 2 problems with this alarm.

1. Random times when I start my car with the remote, and it has been sitting over night, the alarm will go off.

2.Trunk will not pop with Viper alarm.

The shop that told me that they would get my Viper remote working to pop my trunk told me that all they had to do was tap into a wire under my passenger seat. They never said that they had to install a different module. To bypass my factory alarm I had to give the installer a spare key that he could put in this box/module that would bypass my factory alarm which needs to have a key in the ignition to start. What they do is cut the head of the key off so that if someone knows about these modules they cannot break in and use the key to start the car.

 

OK....to answer these questions....
Sounds like my fellow best buy installers in cali are dumbasses...To be able to get the trunk pop to work with any alarm/keyless, an extra relay needs to be purchased (these typically go for $10-15. THe best buy shop will probably tell you it will not be easy to do, due to the fact that the trunk pop is wired directly to the factory alarm. If they were to try and integrate the viper alarm with the factory alarm for the trunk, they would need to use a five-wire diagram for the relay.
However, the easiest way to make the trunk pop to work is to simply cut the trunk pop wire in half. With the half that is going towards the trunk, a positive signal needs to be sent to pop the trunk itself. Off of the viper brain, a negative signal is sent for the trunk pop feature, thus the reason why you will be using a relay. You will be simply reversing the polarity of the signal wire so that instead of being a negative signal to the trunk pop wire, it will be a positive signal thus popping the trunk. Dont believe me? With the wire already cut in half, take the end that goes away from the brain towards the trunk, and using a fuse (very important - don't use anything more than a 3amp fuse), tap that wire to a constant 12volt power source (such as you battery, or your ignition wires under you dash. Very simple.
As for the factory alarm going off - what i did with my alarm is actually ground out the factory alarm disarm wire that comes off of the factory alarm. It should be a blue wire. To be able to test this wire, stick your key into the passenger door, and while using a voltmeter, turn the key to unlock the door. This wire should initially read 12volts, and instantly drop down to 0volts once you turn the key. By doing so, you have effectively disarmed your factory alarm. Therefore, what you need to do is send this blue wire to ground (there's a bolt that holds down the factory alarm - just use this bolt to act as a ground.
As for the explanation as why you factory alarm is going off - many times, if you forget to lock your car, the factory alarm has a built in feature called passive arming, which means it will automatically lock and arm itself within a couple minutes, making sure that your car is safe. When the factory alarm itself is armed and your viper alarm is not armed, and you remote start your car, your factory alarm will go off. That is my best explanation why your factory alarm goes off once in a while when you remote start your car.
As for the problem with CL2.3-Amature's alarm randomly going off - you might want to check to see if your door trigger is still working properly. You can check this by noticing if you dome light turns on when you open your door. If the door trigger is properly working, you might want to take it back to the shop that installed it for you. There's a limited warranty on the brain itself. It might be possible that the brain has gone bad.
Hope this answers a few of your guys questions, or at least informs you a little bit more of our car's crappy factory alarm.

 

How much was all this with install? $350 or so?

 

i bought mine from ebay seller for 230$ shipped. im ordering it tomorrow. installing few people who installed them told me they will do it for $100. now im deciding who will do a better job cuz viper 791xv dere is alot shit to do.

 

So I went back to Best Buy and they tried for about 4 hours to fix it. Couldnt fix the problem. I think he may have been grounding the wrong wires since they're 4 light blues and one dark blue. He seemed like he didn't know what he was talking about. After about 2 more times coming in trying to fix it, the supervisor, installed a 5 wire harness that had defeat on it and the system appears to be fine. I guess the original installer took a shortcut and decided I didnt need that extra harness installed. tsk tsk. no shortcuts, follow directions. I just got it back tonight, so we'll see but it seems to be working fine. The system seems to be disarmed before remote start activates. Awesome. Thanks for all the help guys. This ish was really pissing me off and frustrating me.

Funny story, Best Buy told me that alarm installs are the most dreaded cuz they mess with electronics and what not. Best buy installer blew out a car's entire circuit board and it costed Best Buy 24g's to buy him a new car cuz the car was claimed by insurance as totalled. wow...

 

im gettin viper 791xv installed next week. im getting window roll up installed also for extra 65$. u guys think its worth it? also wut other extra mod should i put in with this krazy alarm system? trunk pop up and ????

 

proximity sensor, tilt sensor, backup battery, pizeo interior siren.

 

the stock 791xv doesnt ahve back up battery does it?

 

it took him 4 hours to do that??? WOW. I could have been done with just adding a trunk pop in about 30 minutes for your car. Sorry to hear about that. Yeah, alarms and remote starts can be a slight pain in the ass, but they're not the most dreaded. I think you're just taking your car to a bad Best Buy. Sorry to hear about those problems.

3zeroCL - no alarms ever come with back up batteries...they must be added. Just make sure you purchase a DEI back up battery. Oh, and that 5 wire harness that you're talking about is pretty much just a relay wired up to be a preventive measure. This prevents backfeeding pulses to the factory alarm to ensure the factory alarm doesn't fry. Hope they didn't charge you for the install on that trunk pop.

babyloc86 - you can also add a sunroof modulator too, but those are a pain in the ass. Another thing - since you purchased your alarm online, DEI does not warrant online purchase alarms - they require you to actually purchase the alarm from an authorized dealer. But just to piss you off, i got mine for $145 through employee discount

If you guys have any more problems with your alarms, just hit me up with a PM

 

i met this cool korean guy who also knew my older friends. he works at bestbuy. his gonna get me the alarm for 150$ + tax. so how much does the backup battery cost?
it will be good to put extra siren also right?

 

backup batteries are $35 i think....and yes, very good idea to have an extra siren - have them mount one underneath the dash right next to the alarm brain. That way the theif will be bleeding through the ears if he tries to steal your radio or your car.