Any relay can be made into a "latching relay". if by 'latching' you mean, you send it a momentary pulse of 12 volts after which it stays on ALL the time, untill the car shuts down.
a relay has four terminals.
A= input for coil ("trigger")
B = output for coil (ground)
C = main pole (source power)
D = post (throw) one. (object to receive power)
say you have a normally open, single pole, single through.
Sending 12 volts to A makes C contact D, thus outputing current (voltage) to whever you desire. Now comes the trick. Take and put a wire connecting D to A. Thus the relay maintains an active state
Now if it's Normally closed, I'll have to charge you for that one
hope I helped
BB414, TH400, 3.73 posi,
13.1sec @ 105 MPH (TH400 needs clutch pack, Radial T/As = zero traction)
"I've seen sunny days that I thought would never end " J.T.
Picture of me roasting the tires and other guy stuff
Video of me staging (smoke of course)