Keyless Remote

[Stocklook]

Sorry if this is an old one,

 

But I opened my remote to clean the contacts, and noticed that the circuit board had 4 terminals or button pads??

 

Is the 3 button Keyless entry the same as the 4 button, same brain but trigger wire not used, and where is the brain,

 

I was thinking about making contact and using a test light to find the trigger wire, but i'm not sure if it is a - or + trigger.

 

I was thinking of using it to honk the horn, For personal amusement.

 

04 ECSB Silverado LS