I am doing an install on my 91 Celsior (LS400) and the instructions say i need a "dedicated ignition circuit" for the power. this is obviously because if i hook it to the constant 12V, the lead will always be hot, even if the car is not running. I believe it needs a dedicated circuit because of the high draw when its on.

my questions are:
1) is there a way to set up a dedicated circuit?
or
2) should i just use a relay from the 12V battery (to power the device) and using an existing ignition to close the relay?


thanks for the help

 

What are you installing?

My not just use true ignition? Black with Orange trace in the ignition switch harness. Don't use the Black/Yellow Ignition 2 though.

 

Installing a Methanol Injection pump. when running it will use a lot of power, and i dont want the circuit i piggyback on to blow.

where is the ignition switch harness?

 

Most of the pumps I just looked up have a 10A draw on them so you should be perfectly fine using the true ignition wire in the Ignition switch harness.
But to be safe you may want to use the accessory wire to trigger a SPDT relay. If Ignition is used then the pump will be coming on during crank. Accessory is Pink/Blue. Run a jumper from Acc to pole 86, ground to pole 85. Run a fused power line to pole 30 and the power connection from the pump goes to pole 87.

Drop the dash and the steering column shroud and the ignition switch harness comes from the key cylinder.

 

the pump is pressure activated so i wouldnt have to worry about the pump coming on during crank.

so can i use the ignition to trigger the relay?

 

Yes, just run it to 86 and wire the rest as indicated before. Don't forget the fuse.

Big Mack