What kind of ignition system are you running....Points or HEI ?

 

Assuming this is for an LS swap. You need to jumper IGN1 and IGN2 together. As the PCM needs switched power in run and start. This is were you hook you switched 12v to PCM.

 

Good catch :tu

 

yes for a LS swap . so tie both them together ( ign 1 and ign2 ) and it runs to computer ?
and he also needs a acc wire too right ,
so that's 2 wires ?
i am running a new #10 from the battery to switch too the other was a little light
a guy is doing the install i am doing some early wiring for him

thanks

 

You will want to run the starter wire through a netual safety switch too.

He should just need a switch Ign and 12v battery wire.

 

i dont have a neutral safety switch , i might have to look into that ,, i also need a acc wire to the puter ,, i dont know where he is sticking that , we talked about hiding it the best he can ,, i would love to have it under the seat ,, but ,,,

thanks for all the help i cant wait to get this car running , i am now doing the PS and PB , and the dash cluster , then i take it to him

later

 

You can use a neutral safety switch mounted it on the column inside.

You don't need an acc wire to the PCM. All it needs is 12v batt. and IGN to the PCM. Not sure what ACC you talking about. Do you mean switched 12v??

 

i thought it needed a accessories wire ? i didnt know ,, i guess once its powered the pink coming out from pcm is the accessory wire sorry , that wire could power different things ,, but because my accessory wire comes from my switch i'm ok
i will look into neutral safety switch
thanks
i dont think my column has one on it i will check

 

i thought it needed a accessories wire ? i didnt know ,, i guess once its powered the pink coming out from pcm is the accessory wire sorry , that wire could power different things ,, but because my accessory wire comes from my switch i'm ok
i will look into neutral safety switch
thanks

There is no accessories wire for an LS PCM. Accessories mean it can be turned on when key is in accessories positions. For the PCM you don't want that. Just Ign. Now you will want your radio for example on accessories. Jumper IGN1 and 2 to give you IGN power to pink wires during crank and run.

PCM
Pink - 12v+ KEY Power Source to PCM. Hot when Key is in the ON and CRANK positions.

Orange - 12v+ BATTERY Power Source to PCM. Hot at all times.

 

got it
thanks again

 

i think the 4l60 has one dont it ?

 

Yes it has one on the side of the trans attached to the gear shift lever. You potentially could use it.

Or just use this which mounts on the column inside. Were the stock nss goes. https://m.classicchevy.com/chevy-ne...com/chevy-neutral-safety-switch-turboglide-and-turbo-hydra-matic-1955-1957.html
Its like 16 bucks and should still do back up lights as well.

 

If Ign 1 is ignition power to keep it running, and Ign 2 is power to the starter solenoid to engage the starter, you can't just jumper them together or the starter will engage in the run position.

I was under the impression that '55 ignition switches ran 12v to Ign 1 when the switch was in the start position. That may not be correct, though. If not, then you need to use a relay to provide power to the "hot in run & start" PCM circuits when in the start position (that's what I did in the '57, which does not provide 12v to the run circuit when the ignition switch is in the start position).

 

There is a separate dedicated wire that goes to the starter its violet in color on a 55/56 switch. It is on its own terminal so no worries it will just run all the time. On a 55/56 switch there is ign 1 and Ign 2 jumper those two and it will work as needed and delete ballist resistor.

The actual switch