Adding Remote Start To An Existing Alarm

I have purchased a standalone RS unit to put into an 03 Grand Caravan with aftermarket alarm installed by a local shop.

The existing alarm is a k-9 classic with 3rd channel output.  If I use the 3rd channel output to trigger the RS, would the alarm go off?

I'm also concerned with the alarm not being able to disarm afte RS since the ignition wire will be energized.

To get around this, would I be alright to use a relay to disconnect the ignition wire from the alarm while remotestarted?

All aftermarket "add-on" remote start units will have whats called an "ignition bypass"  What this does is disconnect the ignition feed to the security system during remote start so it does not false and the remote transmitter works as normal. It is only one wire..not a big deal at all. Now I know DEI products automatically bypass the sensor inputs when using a spare channel to prevent a sensor from triggering..if your system does not have a built in sensor bypass..you can fix that easy with a relay. But first try it because  your sensor may not trigger just from start. If it does take a relay and connect 86 to ignition...85 to ground. Cut the power wire off the sensor and put one side to 30..one to 87a..this will bypass the sensor during remote start only..everything back to normal when the car is off..so simple really. If the system has a neg out during RS..even better..connect that wire to 85..86 to ignition..and 30 and 87a as before to sensor +

Enjoy

Hi master5,

Using the method you just posted, wouldn't the relay be active whenever the engine is running, including while driving the vehicle? It seems like I would be able to lock and unlock the alarm even when the car is running.

Thanks

gcguy...hope that helped.

sorry the other circuit was wrong..been a long week..lol

Take care

Thanks

I just a have a few more questions before tackling this project.

1) Certain functions for this van requires a resister or diode isolate.  Would you just solder a resistor or diode  to it without using anything to protect so it doesn't twist or bend and end up breaking apart?  I know from school that these parts are really thin.

2) Anything that is negative triggered should be safe?  We need to be more cautious of positive triggered inputs?

3) The kit does not include anyting to allow for the powerwire to be attached to the battery. What part do you use to attach it?

The best way to connect diodes and resistors is with solder and shrink tube..just be careful not to overheat ..you can use an alligator clip or small plyers as a heat sink..if you don't have shrink tube you can use a quality electrical tape but regardless make sure you insulate the leads for a safer installation. If you can't solder you can use small ga. butt connectors but pull on the connection to make sure it's solid and insulate and exposed leads. I don't like using connectors for that but it can work if done right. Use zip ties to secure everything so it won't pull apart if stuff gets moved around.

The main reason it is stated to be more cautious with positive outputs is because in a vehicle there is alot of exposed metal and if anything positive touches it..you have a short. But this is not to say you should be careless with negative or any other connections..for a safe and reliable installation every connection should be solid and well insulated.

For most  systems I connect my power connection by soldering to the constant at the ignition harness and fusing it there. However some newer vehicles have lower current constant at the harness..you can tell if it is not at least a 12ga. or larger. Some just prefer to always go to the battery regardless. If you choose to go directly to the battery use at least a 10ga..and fuse it close to the battery. Use a ring terminal to a bolt on the terminal if top post..if side post you should use a post extender. If there is a junction off a heavy gauge wire from the battery already you can connect there as well.