I am wiring a Model A coupe with a flathead V8, 12 volt negative ground system. The harness is a universal type (Speedway 12 circuit) with GM style plug-in column ignition. I would like to use a single wire start button like this: With a 1936 Column Drop Ignition Switch: The harness ignition instructions list the following ignition wires and their destinations: If I understand this correctly I would connect the Red Power wire to one post of the switch and both the Pink Coil wire and Brown Ignition wire to the other post. Does that sound correct? Also would I connect the purple Start wire to the start button? The button is grounded to the dash. What would I do with the Orange Accessory wire? There are no ACC terminals on the column drop switch. I am not running any radios, fuel pumps or wipers on this build. I posted on the Ford Barn but couldn't find anyone that had done this before. I was hoping that someone on the Hamb had wired their hot rod in this fashion. Thanks for any help you can offer. Tony
It looks like the purple wire probably goes to the starter solenoid. This wire should go to the ignition on side of the ignition switch, then to your push button. The other side of the button goes to the starter solenoid. Confused enough yet?
I think you will need a two wire start button. Check this thread, to see if it will help you: https://www.jalopyjournal.com/forum/threads/eliminating-51-ford-push-button-start.1244738
That looks like a late 40s to early 50s and beyond Ford door jamb switch That supplies ground when the door opens. Can you show a picture of the backside where the wire or wires connect to? A “ground when open” switch can be made to work with a relay but a two wire switch would be much easier.
Here is a two wire button: https://www.napaonline.com/en/p/ECH...Ps7TNC2qLSSHgqMpYYaAmzEEALw_wcB&gclsrc=aw.ds&
Get a Standard Ignition SS587 starter relay/solenoid. This is the 12 volt version of what the flathead probably used to begin with. Connect a wire between your button and the small terminal on the relay, your starter will operate anytime though, ignition switch on or off. If going automatic run that wire through a neutral safety switch. If you want it to be ignition switch controlled you'll need to get a 2 wire starter button, different starter relay/solenoid also (not the SS587).
Thanks guys, yes I am confused. I have a 4 post 12 volt solenoid in place already. The button I have is an NOS that was used in 30's Fords. It has one wire and is grounded to the dash. If I can't use it then I am open to getting a 2 wire button but I really would like to verify that the one wire is unusable. My main questions have to do with the wiring to the ignition switch terminals. Once I get that squared away I can get onto the button. Thanks
You may find some help here: https://www.jalopyjournal.com/forum...single-wire-momentary-starter-switch.1188922/
I was given this wiring advice from a helpful poster on the Ford Barn: Using a relay: run the red wire to 30 on the relay and add a jumper to 85 run a wire from one terminal on the ign switch to 86 ground the other terminal on the ign switch connect the pink, brown, and orange wires to 87 He also commented that I could use my single wire start button using another relay and wiring it as such: Connect 30 to one of the unused ign or acc circuits on your harness also jump to 85 connect the purple wire to 87 and the other end to the S terminal on the starter solenoid connect the starter button to 86. Wired this way the starter will only work when the key is on.
Do yourself a favor and build your own harness. A lot of nonsense in those universal kits for your application. And you’ll know the whole system which will help with troubleshooting down the road.
On the other hand, the first relay allows him to use the modern harness without overloading the simple brush contact in his stock ign switch and second permits him to use the starter relay he has already mounted as he requested. I shouldn't think the two relays are an overcomplicated approach to achieve his goal. For reference here are a couple sketches of the wiring.