dodge caravan aftermarket alarm

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=116567
Printed Date: June 03, 2024 at 9:16 PM

Topic: dodge caravan aftermarket alarm

Posted By: aviator172
Subject: dodge caravan aftermarket alarm
Date Posted: September 27, 2009 at 12:55 PM

Does anyone know the actual VOLTAGE that need to be applied to the BCM for LOCK, UNLOCK, ARM and DISARM?

Not just the resistor values, but the actual voltages?

Also, on the 1999, is it correct to connect ALL 4 aftermarket alarms wires (lock, unlock, arm, disarm) to the SAME wire on the vehicle? (white with dark green stripe).

thx

Replies:

Posted By: Steven Kephart
Date Posted: September 27, 2009 at 1:22 PM

1. When doing resistive door locks, always use relays. That will get you a strong enough signal. You can't just series a resistor with the door lock wires out of the alarm brain.

2. You don't need to use the arm/disarm wires as the factory alarm system arms/disarms with lock/unlock. Just run the lock and unlock wires to their own relays, then have the output of the relay sent through the proper resistors and then to the vehicle wire.

Posted By: aviator172
Date Posted: September 27, 2009 at 3:03 PM

Thanks Stephen,

Through trial and error I find you are spot on. I had been trying to use 4 wires from the aftermarket alarm...

1). Heavy gauge unlock wire (it's from an internal relay in the aftermarket alarm)
2). Heavy gauge Lock wire (also is from an internal relay)
3). Very thin Disarm wire from the aftermarket alarm
4). Very thin Arm wire from the aftermarket alarm

Turns out as you stated, only two wires were actually needed...the two heavy wires that were from the internal relays.

The other part of the problem was that the values listed for the resistors on several popular tech sites that were needed were incorrect and did not work with those values be it for whatever reason. I had to experiment with a few different resistors to get it to work....thereby slightly changing the voltage presented to the BCM module.

At this point I do not "think" I need additional relays as the wires from the aftermarket alarm were already from an internal relay. Please advise if you think this is not correct. The Factory manual for my vehicle states that the relay handles 20A for the door lock/unlock circuits and that is the stated capacity of the internal relays for the aftermarket alarm as well.

Thanks again for everyone's help!

This one has a happy ending....finally posted_image

Posted By: Steven Kephart
Date Posted: September 27, 2009 at 3:44 PM

aviator172 wrote:

The other part of the problem was that the values listed for the resistors on several popular tech sites that were needed were incorrect and did not work with those values be it for whatever reason. I had to experiment with a few different resistors to get it to work....thereby slightly changing the voltage presented to the BCM module.

Here's what Directechs specifies for the values for your vehicle:

"Use relays and set up for negative trigger. Place a 4020 ohm resistor inline on the lock output, and a 665 ohm resistor inline on the unlock output. If you do not have a factory security system use a 1500 ohm for lock and a 250 ohm for unlock."

aviator172 wrote:

At this point I do not "think" I need additional relays as the wires from the aftermarket alarm were already from an internal relay. Please advise if you think this is not correct. The Factory manual for my vehicle states that the relay handles 20A for the door lock/unlock circuits and that is the stated capacity of the internal relays for the aftermarket alarm as well.

Thanks again for everyone's help!

This one has a happy ending....finally

Does it actually say 20a or 20ma? If they use actual high current relays for the lock outputs, then no you won't need external relays. You didn't list an alarm model, so I can't be sure.