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I'd like to wire up a circuit that provides 12volt power to the bed only when the doors are unlocked. The first question: does anyone know if/where I can tap into something that I can use to trigger a relay when the doors are unlocked, and then switch off when I lock them. (2007 Double Cab)

If anyone has general suggestions on how to approach this problem, that would be great too!
 

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J.O.A.T, Master of none
'14 Tacoma DC/LB
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2,691 Posts
Well...here's the first possible problem. If you want a relay to be ON only when the doors are unlocked, that means that the relay will be energized all of the time when the doors are unlocked, that may be a drain on the battery if you were parked for a long time, say while you were away for vacation and your truck sits in the garage. A relay coil such as this may draw .02 to .04 amps which isn't much, but may eventually drain it.

I guess you could tap into your lock and unlock pulse with a couple relays. I have done this on a Chevy, a Pontiac, and a GMC for remote door locks.

Dusting off my Electronics training.... here goes....what if you triggered a relay (R1) with the unlock pulse and that relay was wired in a latching configuration. By latching configuration, I mean apply 12V to a set of normally open contacts and the other side ties to the coil of the relay along with the unlock pulse wire. The 12V is sitting there on an open contact, but once you close it (via the unlocking pulse) the 12V feeding thru the contact feeds the coil and it won't let it release. Then you wire another relay (R2) to the lock pulse, the normally closed contacts of that relay (R2) is in series with the relay coil of the other relay (R1). This way when you unlock, the 1st relay (R1) latches and holds, when you lock, the normally closed contacts of R2 in series with the 1st relay coil opens and allows the 1st relay (R1) to reset. After all of this, you feed 12V thru a different normally open contact on R1 feeding your bed power..with a fuse of course.

To further complicate things, some vehicles are positive pulse locks, others are negative or ground pulse locks. I laid this out as if the vehicle is positive pulse. If it's ground pulse, that throws another wrench into it and may require a different wiring configuration.

Maybe a drawn out diagram would help if this doesn't make sense....


Whewwwww....... :hammer:
 
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