Neutral start switch

When using the Ford style firewall solenoid you can't use the ones that have the "I" and "S" terminals, you have to get the type that has two un-labled terminals and then run the Start wire to one terminal and the other terminal goes to the center pin on the Mopar NSS.

At the Mopar starter you will need to run a jumper wire between the large terminal and the smaller "S" terminal.

No special attachment to the Ford relay other than the fact I have all the wiring under the hood done. I'll look into the un-labeled Ford relay since it would be a simple swap out.

Thanks everyone for the help.

Wow, thanks John.

Just a few questions. I am using the old starter button. I assume the wire from the start switch replaces the wire from the starter button to the Ford relay. Also, it was hard to read, does the wire going to the starter solenoid go to the start wire (small wire) or the battery cable wire (I am guessing the small wire)?

Can I get this at NAPA?

learning some thing here,,,

OK, we're interchanging the word "relay" with the word "solenoid"....the ISO relay in my drawing will be added to the start circuit and energizes the existing Ford solenoid. The ISO relay is available from many sources, just ask for a "30 Amp ISO Relay"....most come with the connector and short pigtail wires.

The solenoid I'm referring to is the existing Ford firewall solenoid; the existing wire that now goes from the Start button to the solenoid "S" terminal is interrupted by the ISO relay in my schematic I.E. the existing wire goes to terminal 86 and jumpers across to 87. The wire from ISO terminal 30 goes to the "S" terminal on the existing solenoid and terminal 85 goes to the center pin on the NSS. This way the starter will only be powered in Park and Neutral by a ground from the NSS.

As before, in order to use the Ford solenoid with the Mopar starter you will need a jumper between the two terminals on the Mopar starter; this is assuming you are powering the Mopar starter large terminal from the Ford solenoid large output terminal.

But if you are hooking the battery positive cable directly to the starter and using the Ford solenoid only as a relay, no jumper is needed and the output side of the solenoid would go to the small "S" terminal on the Mopar starter.

Confused yet?

I got it John. I only have to mount the new ISO relay under the dash, interrupt the start wire from the starter button to the S terminal on the Ford relay and wire it to the ISO relay in two spots and then run one new wire down to the neutral start switch. Oh, and add small jumper wire at the starter solenoid since I am using the start terminal on the Ford relay.
Yeah, I was confused about the use of "solenoid". I've always called the thing on the starter that engages the bendix gear a solenoid. Anything else I call a relay. But I have heard many people call the thing on the Ford firewall a solenoid.

Anyway, it's all good. You're the best, thanks for the help. If you get to Florida, I am buying...

essentially, the difference between a solenoid and a relay is the amount of current they handle. They function the same. They both use an electromagnet to engage a set of contacts, in the case of a starter solenoid it will also engage the bendix.

OK, an update and final closure on this issue from me. Went to NAPA today and gave them John's spec's for the relay. Few minutes in the books and counter guy has part number and they have it in stock. $13 later, I am out the door. When I get the relay home I thinking I've seen this before. Went digging through my electrical parts and sure enough, I already had one. Spare horn relay. Guess I have a backup for my start wire up now too.

Hooked it up per John's diagram and it was golden. Starter button cranks motor in park and neutral only. Didn't need the jumper wire at the starter solenoid since my battery cable goes direct to the starter. Small wire on MOPAR starter goes back to output side of Ford relay (solenoid) on the firewall.

Just want to say thanks to everyone, esp. John for the help.


Here's a pic of the wired engine....

On edit: The NAPA part number was AR272 in case anyone needs to do this in future.

great to hear it all worked out for you