aftermarket alarm problems

[VENUM INJECTION]

I need some advice. I recently had an aftermarket alarm installed on my 08. It is made by a company called Viper. The first stereo place said they had done work on Viper cars as well as other high end cars and they have been around in my area for about 20 years. So I trusted them. I was moving out of the area, and the day I was to leave and also pick the car up from this audio place the alarm did not work. So they made arrangements to send me to a different audio place at my destination and pay to have them troubleshoot it. This new audio place told me they could not believe how sloppy a job the first place did on installation but fixed the alarm. Now when they brought me back to show me the alarm they asked me why my windows did not roll down. I told them my windows worked fine before I dropped it off. So now I bring it to the viper tech in my new area, and without looking at anything he tells me to tell them to rip it out and go back to stock. This the same tech who says he has never seen an 08. Great!! So now I call my Viper tech back home and he says the two systems may be working against each other and to bring it back to the audio place and have them go over it all again. I know this was a long winded way to say has anyone else had a similar prob. to this? One other point, the windows have power because they move up to seal when the door closes, they just won't roll down when I hit the power window button. Any help would be appreciated. Thanks-Chris

 

[EZ 2B Green]

Well, here's my .02. Based on your story, I would return to stock. The reason being, the guys that are supporting you and/or selling you car alarm stuff do not understand the Viper's electrical system in my opinion. You risk more damage having guys not understanding what they are doing, work on your 90K car.

Here's a likely possibility why your windows are not working properly. Please understand without knowing what these guys did, it is just an educated guess.

Many older automotive electrical systems work by sensing or supplyng a ground or 12 volt power to operate. For example, pressing the power window switch one way (up) provides power to the window motor in one polarity and pressing in the other direction provides power to the window motor in the opposite polarity (down). This is done with simple wire and switches. Modern vehicles like the gen 4 Viper use a body control module (computer) to control everything. Switches in the vehicle for the most part do not apply power or provide a ground to operate any circuits. Instead they provide a signal to the computer and it controls the window, door lock etc...
Since the computer only needs a signal the engineers cleverly used resistors in the wiring harness/switches to save the amount of wiring needed compared to pre-computerized electrical systems. So a 2000 ohm resistance seen by body control module from the power window switch may mean raise the window and a 1000 ohm resistance from the power window switch may mean to lower the window. Now if you don't know what you are doing, and you start tapping into the control wires (which many aftermarket systems require) you can upset the resistance values so that they are out of range (ex. 500 ohms instead of 1000)
and the computer no longer recognizes this as a valid command and does nothing. This is what I suspect happened in your case. There are ways to properly do this but you need someone with above average electrical knowledge to interface to the computer.
In case you are curious, I have been able to interface to my 08's computer without any issues but I have a college degree in electrical engineering/computers. Good luck!

 

[VENUM INJECTION]

I really appreciate your feedback. That makes a lot of sense. I hate that I will possibly have to eat 800 bucks.

 

[steponz]

Had a very similar story... I ended up bringing it to very qualified installer..

They put it back to stock and then did it over again....

Joe

 

[mjorgensen Woodhouse]

The possible frequency interference between the alarm and the electrical system of the BCM may be fighting each other also as above. We have seen this with the installation of some iPod adapters also and the only way to fix it is to change back to stock unless the is a RF type of alarm which I doubt. The factory alarm is a decent system for a factory one and you should really not need the trouble of the aftermarket one anyways. Are there any codes that the Viper Tech pulled up when you last went to him? This may give an indication of what is malfunctioning.

 

[VENUM INJECTION]

The Viper tech wouldn't even check it out. He just said our recommendation is going to be to take it back to Factory specs no matter what. I should have insisted but the tech came off as if he had not seen a viper in a while, so I really didn't want him touching it anyway. The shop that installed it said they would go back over it. I feel like it is more risky at this point to have that shop take it back to spec because of all the wiring that would have to be saudered just right. I am bringing it back this week so we will see. Thanks ya'll.

 

[EZ 2B Green]

I recommend that you invest in a 2008 Viper factory service manual (the hardcopy). It has the complete electrical diagram for the car. It will be invaluable if electrical gremlins continue to crop up. Tell them you are a VCA member and you will receive a discount.

https://techauthority.gltghosting.c...rHome?storeId=10051&langId=-1&catalogId=10051