791xv lock problems

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=84858
Printed Date: May 13, 2024 at 1:17 PM

Topic: 791xv lock problems

Posted By: c0ckeyed00
Subject: 791xv lock problems
Date Posted: October 30, 2006 at 3:12 PM

Hello,

I've had this alarm in my 02 Ford F250 for about a year now. Just yesterday, I noticed that when I arm my truck, I hear them try to lock but don't. They make noise, but don't lock. The locks sound sluggish. I can use my power lock switch and they lock and unlock just fine. Any suggestions?

Replies:

Posted By: Big Dog
Date Posted: October 30, 2006 at 3:26 PM

Vehicles with keyless entry, the lock wire is simple negative trigger. A ground problem would cause problems. If you send a ground into the green or blue lock wires exiting the 791 and the locks work, then add relays.

If it's not keyless entry then it's 5 wire reversal and relays should have been used. Sometimes they're incorrectly interpreted as positive trigger by the installer and blow the lock/unlock transistors in the 791.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Posted By: c0ckeyed00
Date Posted: October 31, 2006 at 1:52 AM

so just add a relay to directly ground the lock wire?

thanks for the help

Posted By: Big Dog
Date Posted: October 31, 2006 at 8:55 AM

NO. Not necessarily. Just follow the steps in my previous post because we haven't discovered what was installed nor how it was installed yet. Is it negative trigger or 5 wire reversal? We don't know until you take a look.

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Posted By: c0ckeyed00
Date Posted: October 31, 2006 at 10:00 AM

Oh. haha. It's a negative trigger. Should I look around for a look or bad ground?

Posted By: Big Dog
Date Posted: October 31, 2006 at 10:23 AM

Yup.

Sometimes the ground will have resistance over time and cause a voltage drop to the point where the lock output is not really sending a true ground. In a worse case scenario, you can always add relays to boost the ground out of the security system.

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Prepare your future. It wasn't the lack of stones that killed the stone age.