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2004 explorer & 791xv problems need help

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=42492
Printed Date: July 13, 2025 at 6:23 PM


Topic: 2004 explorer & 791xv problems need help

Posted By: Integrity
Subject: 2004 explorer & 791xv problems need help
Date Posted: November 08, 2004 at 8:02 AM

I need help I have a 2004 ford explorer xlt & I purchased a viper 791xv. the problem that I am having is sometimes the vehicle starts normally other times the display tells me the car is on i go outside and the car is attempting to turn on but it does not.

I had the same problem with a nissan altima that i had so the delearship told perhaps the alarm module was messed up so they charged me 80 bucks and it still does this and DEI aka directed electronics will not help me out because i am not a dealer.

can someone please either post a solution or the wiring diagram for this alarm install on my car I need help bad I have two little girls that will appreciate the car being warmed up each morning for the winter. Thank you all ahead of time



Replies:

Posted By: daniel2002p
Date Posted: November 08, 2004 at 8:16 AM
which tach wire are you using?

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Posted By: misterjimbo
Date Posted: November 08, 2004 at 8:18 AM
What exactly is the car doing? Is it attempting to crank? There is a factory led in the center of the dash in a transparent black dome. When you try to remote start the car does this light come on for 3 seconds and then go off? Or does it start flashing real fast? If it flashes fast then there is a problem with the bypass for the pats. The main wires you need are ign red /green acc BLACK/ green starter red and I do not remember the constant. You do not have to power up ign 2 or acc 2 for remote start.
If it is not that, it could be a tach concern. Dei has several adjustments for their tachless operations.     

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Posted By: Integrity
Date Posted: November 08, 2004 at 8:31 AM
I have no idea about tach wires or anything I have someone here that knows more about this but he needs the diagrams cause i dunno anything




Posted By: misterjimbo
Date Posted: November 08, 2004 at 10:16 AM
The tach wire from the alarm is purple with a white stripe. On the car you can go to an uncommon wire on the coil

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Posted By: Integrity
Date Posted: November 08, 2004 at 4:58 PM
so this PURPLE / white wire should go to tach wire? oh yeah someone also mentioned that this alarm can control my tailgate to add a relay is that something i can do? cause whats a relay anyway i am clueless to automotive stuff




Posted By: Integrity
Date Posted: November 09, 2004 at 8:13 PM
so i went to the dealer today i was under the impression i was going to get the tach wire installed. little did i know that i was told they do hundreds of alarm install's and they never had the need to use a tach wire because he said these cars no a days are all computerized if you run a tach wire and you have problems where the tach wire shorts you can fry your cars ecu and then you will be out of luck.

he also mentioned he is following directed electronics wiring diagram

so what he tried was he pluged in this pda looking thing into the car alarms module box thing and he ran some diagnostic and then he changed the crank timing to 1.0 he told me to try that and see if it works right so i will be starting the car out everyday as much as possible to see if it does the same problem. is this information useful or are they still bsing with me




Posted By: auex
Date Posted: November 09, 2004 at 8:30 PM
He is lying point blank. I bet he didn't even install a hood pin either. Here is the 791's install manual just so you know what is supposed to be hooked up.

Also the PDA thing you are refferring to is called a bitwriter and has no diagnostic menu's at all, again if he said that he was running diagnostics then he is lying.

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