relay design

Hi, I would greatly appreciate all the help I can get from the members. I have a need for a relay but unsure how to do it. Basically i have and E-brake that will be negative (- ground) when the parking brake is pressed and feed to the radio for other purpose. My goal is to cut this wire and put a relay between the ebrake wire and the radio wire and controll it with an on/off switch to create a bypass. So when I turn on the switch On, it constantly feeds the negative ground to the radio regardless the E-brake position. When I flip the switch to Off mode, it will then no longer create a bypass. Basically it backs t the factory/originall wire. By taking the feed from E-Brake (just as the line never been cutted from the ebrake to radio It will then re-attach the wire from the back of the radio back to the other side of the Ebrake as it was never been cut. Orginal a)     Brake depressed --> E-Brake wire pass the negative feed from E-Brake --> to radio b)     Brake not depress --> E-Brake wire not passing anything --> to radio Goal E-Brake is not depress and the [switch is ON] --> [Relay Module] --> Relay need to feed constant negative ground --> to radio Regardless E-Brake possition and the [switch is OFF] --> [Relay Module] --> Passing/taking the feed from E-Brake input(just as the line never been cutted from the ebrake to radio. Basically, back to the factory/original setting a) and B) above) --> to radio thanks all

Why don't you just use a toggle switch inline with the parking brake wire?  I don't see a need for a relay in this case.Kevin Pierson

It was my first choice but unable to do it when combine to disable the VSS line. Without a second relay for Ebrake, I don't see how I'm going to disable the VSS and ground E-brake together with 1 relay and 1 switch.

oh, it is 09 maxima. I like to be able to let me kid watch the video while I'm driving instead of getting another headrest video player. At the moment the only way to watch it via the information center is the vehicle must be stop and the e-brake must be on.

unfortunatly i dont think anyone can help you on this one, check out the forum rules.