This will enable you to add additional Amplifiers, Fans, or any other device(s) you would like to turn on with IGN.

Mark

EDIT: Pin 87A isn't needed in the insance, it's the Normally closed, (N/C) terminal...

 

What is the center pin (87A) used for?

(btw... please edit your original post to include it.. .then I'll just delete this one to keep it clean)

 

I believe that 87A receives power from 30 when there is no voltage present at 86. Then when 86 receives power, 87A loses power and 87 receives power from 30.

Simple answer - 87A will receive power when the system is off.
I think that's called a double throw relay.

 

so this is for if you have more then one amp? y cant u just link them

 

^ hooking several amps up to the remote turn on lead from a deck is usually OK... but the lead generally won't provide more then a few hundred mV.. so if you also want to run fans, lights, or whatever, you will need to use a relay with a seperate power wire from the batt...

 

oh ok i see. thank u sir

 

I believe that 87A receives power from 30 when there is no voltage present at 86.

 

cool thanks guys.

 

i like the post but wouldn't you want to have terminal 30 going to your electronic device and have the +12 volt going in through terminal 87A? that way your not makeing a loop from terminal 30 to terminal 87 running the chance of shorting out the center terminal?

 

If you did that, your electronic device would be active when the relay is at rest. Then the moment the relay activates, your device connected to 30 would lose power because 87a would no longer be connected to the circuit.

I'm guessing that you haven't seen the guts of one of these relays. 87 and 87a are 2 "options" for 30 to be connected to - 30 and 87A when the realy is at rest (when there is no voltage at 86); and 30 and 87 when voltage is present at 86. The way they work is there is wire that goes up from 30 and is connected to a "bar" that is hinged above points 87 and 87A. There are springs that hold this bar against 87A. So there is continuity between 87A and 30 when the relay is at rest. When the relay activates, it activates an electro-magnet that pulls the bar away from 87 and makes the bar have contact with 87. Now 30 and 87 have continuity.

Because this bar is hinged between both 87A and 87 there is never a point when 87 and 87a can have continuity with each other or short each other out.

I hope this helps.