Why do you need a relay?

Hola,

I just found this site by mistake, and I'm learning so much!  But I have a pretty general question.  I know how to hook up a relay for the trunk release, dome light supervision, or horn honk, but I don't understand why you have to?  And then I don't need one when I hooked up an aftermarket remote starter to an existing alarm.

The wires for the alarm that I'm hooking into are:

• 1.  Channel Two ( - ) output 300mA      :  I'm going to hook up the trunk pop to this
• 2.  Channel Three ( - ) output 300mA   :  I'm going to hook up the wire from the remote starter to this ( so I can use the alarm's remote instead )

I believe the trunk popper I'm installing is a ( - ) pulse as well.  So, I guess I don't understand why you need a relay for the trunk if they're both ( - )....but then you don't need one for the remote start wire?

Thanks!  (I'm learning)

1. You need a relay to boost the signal that the channel 2 output is giving. Most RS or alarm systems (-) output is not strong enough to actually throw the trunk release solenoid over to engage the pull.

2. Make sure that the remote starter that you have or purchasing has a remote starter (-) input activation wire so that you can incorporate the alarm system to control the remote starter.

Yea, for the  ( - ) input activation on the remote starter....I used the blue wire below:  I hope that was correct.   It works, I just hope I didn't need a relay...I don't think I do.

No image, but if it works now without the relay inplace, then you shouldn't have a problem, but make sure that the input activation doesn't require mor ethan 500 ma (-) otherwise, you will want to install a relay for this circuit so there's no long term damage to the module.

No image, but if it works now without the relay inplace, then you shouldn't have a problem, but make sure that the input activation doesn't require mor ethan 500 ma (-) otherwise, you will want to install a relay for this circuit so there's no long term damage to the module.

I tried to get the diagram above to come through....I hope it works for you.  How do I know if it requires more than 500 ma (-).  Like I said, it works, but I wouldn't want to kill the remote start module if it's supposed to have a relay.  Like, if you hooked it up to the trunk pop without a relay, it would probably work, right, but kill the module eventually?

Thanks!

According to the diagram , there is no trunk release wire ( at least none shown ) so I'm not sure what your maximum activation current is. It will say on the installation instruction  you have, look it up and see what it says about this wire.