adding a back door trigger

I have a Toyota truck with a custom Camper shell The shell has two hinged doors I like to put triggers on the these doors.There,s no clearance between the shell frame and the door frame for a factory door trigger. I have a NC magnetic button switch. for this to work I think I have convert it to a NO switch with a relay and then connect it to the the same wire with diodes the truck cab doors are wired to. Is there a better way to do this? can someone tell me how to wire the relay Thanks Mark

A house alarm magnetic switch may work also. Or you could get a motion sensor for the cab and sense if someone opens window and tries to get in. Or a mercury style hood tilt switch mounted to the door part that goes up. You can get one of those at a Ford dealer, we normally get those when we install OEM Ford remote starters.The wire I'm test'n isn't doin' what it's supposed to be doin'... I am so glad I printed that tech sheet, with the wrong info.

Do it right the first time... or I might have to fix it for ya