viper 791xv doors will not unlock

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=120157
Printed Date: May 08, 2024 at 8:10 PM

Topic: viper 791xv doors will not unlock

Posted By: bigsquid78
Subject: viper 791xv doors will not unlock
Date Posted: February 16, 2010 at 1:13 AM

Hi I have a 1998 ford explorer xlt. I had an viper 791xv installed on it a few years back and has worked perfect till I came home one day and it would not unlock the doors when unlock was pressed. It will disarm the alarm but will not unlock doors. I can use factory remote and doors will unlock. If I hit lock on viper remote it will lock doors and arm system as usual. also when the truck is running in remote start neither remote will unlock the doors. All other features work. any Ideas on what the problem might be?? thanks

Replies:

Posted By: sneakycyber
Date Posted: February 16, 2010 at 1:25 AM

I would check for a loose connection in your door lock wiring with the alarm system. It could also be a fuse, since there is a possibility of reverse polarity some installers use fuses with the relays. As for the locks not working when the explorer is remote started Since the alarm is not working properly it can't unlock the doors and the factory key-less may not work with the engine running.

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Posted By: bigsquid78
Date Posted: February 17, 2010 at 12:20 AM

I looked and found nothing loose. If It was a bad fuse would it still lock the doors??

Posted By: tedmond
Date Posted: February 17, 2010 at 7:00 AM

yes it would work even if a fuse was blown.

meter the output wire on the viper and see if it still works.

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Ted
2nd Year Tier 1 Medical School
Still installing as a hobby...pays for groceries
Compustar Expert

Posted By: t&t tech
Date Posted: February 17, 2010 at 2:02 PM

Highly unlikely it's a fuse! If the setup is reverse polarity, it could be a relay or the feed of the unlock output from the 791xv! The possibility of it being either are nearly equal, since they rarley ever go bad!

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COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF. PSALMS 37:5

Posted By: tedmond
Date Posted: February 17, 2010 at 5:10 PM

woops i have info as this truck as neg locks, not reverse polarity.

thought he was talkin if a fuse on the 12v line of the viper blew, if locks would still work.

but if it is set for reverse polarity, check for any loose connections/blown fuses. With the unlock relay, take the wire that comes from the viper and tap it to ground. if the relay clicks, it means the relay is still good.

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Ted
2nd Year Tier 1 Medical School
Still installing as a hobby...pays for groceries
Compustar Expert