latching circuit

Can anyone draw a sch on how to wire a latching circuit? I need to install 2 switches in my truck to control tc lockup and od shift. I have looked on this site and have learned a lot i am still confused about a few things. For the tc lockup it ises a groind to signal lockup. I want to use a latching circuit to hold lockup using a dpdt momentary switch ontil i push on the brakes. The brake swittch uses a 12vfew signal. I know i have to switch polarity on the brake signal and cam do it with a relay. But here is where i get a bit confused. The od shift is a ground signal as well And i should able to use a dpdt switch to ground the signal. Any help would be great i have been chasing electrical issues with this truck for ovet a year and i need it back bc my qife is expecting our first child and i need it for family transport. Thanks in advance.

Truck is a 98 dodge ram 12v diesel with auto trans.lost all my gauges electronic shft trans wont shift in id or lock also alternator wont charge pcm keeeps getting fried.

Shown is an Omron dual coil latching SPCO, also available in DPCO format: 79C_latch.bmp As long as you observe coil polarity you could have a constant neg (-) and switched pos (+) or vice versa. If you look down on some of these relay posts it will give you the correct part numbers, Farnell or Mouser in the US stock them. Sorry it's 12:15am here and I'm too tired to start Googling for you..Omron latching relays. Up to about 10 amps current handling.

Omron part numbers:- 5amp/12VDC G6BK-1114P-US-DC12 10amp/12VDC G6CU-1114P-US-DC12