Help with 36 Column Drop Ignition

N

nb141fd

Senior Member
I'm installing a 12 circuit wiring harness on 12 volt, negative ground Flathead powered vehicle. I've come to a stumbling block in wiring my 1936 Column mounted ignition switch. I'm planning to use a dash mounted start button like the one below.
full

On the back of my ignition switch are two posts which I'm confused about wiring. My problem is that I am using a universal Speedway 12 circuit wire harness and don't know which ignition wire goes to which post.
full

My harness instructions are as follows:
full

-My assumption is that the red wire (Ignition Switch Wire) goes to the battery post on the ignition switch and the pink wire (Ignition Switch Coil) goes to the other post, but which post is which?

-The orange wire (Ignition Switch ACC) goes to the Accessory terminal on the switch who's location is unknown to me.

-The brown wire (Ignition Switch IGN) goes to the same terminal as the pink wire.

-I believe that the purple wire (Ignition Switch Start) goes to the start button?

As you can tell I'm not very well versed on automotive electronics so any help you can provide will be very much appreciated.
Tony
 
The switch on your column drop is designed to power the ignition only--it is merely an "on/off" switch. One side is hot and the other side goes to your coil, doesn't matter which side. I wouldn't connect anything else to it--it isn't heavy enough to carry many amps. It shouldn't be the switch for any accessories--they all should be on separate circuit(s).
 
Thanks swedishsteel, I'll wire the red to one post and both pink and brown wires to the other post. Am I right that the purple (Ign Switch Start) goes to the one wire start button which is grounded to the dash?
 
Am I right in assuming that the orange wire (ign switch ACC) can be left out since I don't have any accessories; radio, heater etc...?
 
I suspect the brown wire provides juice to the signals, wipers, fuel pump, etc, which may be in excess of the stock switches capacity if you have those items. I feel the signals alone would be too much load for the stock switch.

I don't remember there being an actual schematic with the Speedway harnesses I dealt with. May take a little circuit testing to see which fuses/circuits the brown and orange wires actually power.

The purple start wire can be used for the grounding start button, if the other end is connected to a grounding starting relay.

I usually use the stock ign switch to switch a power relay to limit the current load on the internal brush and contact of the stock switch.
 
Sounds like The harness is designed for a modern key operated switch which utilized the circuitry listed on the sheet. Have you installed a solenoid?
Ideally you can use your column drop switch to activate a relay.
 
Thanks RichB and CA Victoria. The only thing I’m running on your list are signals. I do have a four post solenoid installed. Your right, the harness while universal, is designed for a GM plug-in module on the column. I pulled the wires from the module and am attempting to wire them to my 36 drop column switch and start button individually. I’ve been searching for a couple of days for someone who has gone through this dilemma while wiring a hot rod and have come up empty.
 
the answer above is right on the money, i have been using my original switch for 10 yrs wired to a relay to power the other systems. paul
 
Thanks Paul, do you happen to have a diagram or reference showing what is wired to the relay? Thanks, Tony
 
There is a thread here about using relays to power the original switch, sorry I dont have it bookmarked. I use a relay in my 34, and have it wired so that when you turn on the ignition, it grounds the relay to energize it.
 
No picture handy:

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


If you want to use the late model starter solenoid you have with the stock grounded start button, it can also be controlled by a relay.

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.
 
Diagrams for above post
 

Attachments

  • IMG20220808065027.jpg
    IMG20220808065027.jpg
    25.4 KB · Views: 26
  • IMG20220808065006.jpg
    IMG20220808065006.jpg
    28 KB · Views: 22
Thanks very much for the help rich b. A couple of questions if you don't mind. It looks like only two wires go to the actual switch terminals; one from the relay pin 86 and the other from a good ground, right? My other question is what relay amp ratings do you recommend?
Thanks again, Tony
 
Would these work?
61xmReZuigL._AC_UY218_.jpg


EHDIS Car Relay 4 Pin 12v 40amp Spst Model No.: JD2912-1H-12VDC 40A 14VDC, Auto Switches & Starters,Pack of 2
 
Not familiar with the brand; but that style relay will work.

Yes, just those two wires on the ign switch; it is only activating the relay which in turn powers the coil (pink) along with the ign on circuits (brown), and acc circuits (orange).

Don't overlook including a proper ballast resistor somewhere in the coil circuit.
 
Thank you gentlemen.

rich b I will use the Orange Ign ACC wire on the start button relay pin 30 if that's OK.

Tim, thank you for your generous offer but I've ordered the two relays shown in the pic.
Thanks again
 
nb141fd said:
Thank you gentlemen.

rich b I will use the Orange Ign ACC wire on the start button relay pin 30 if that's OK.

Tim, thank you for your generous offer but I've ordered the two relays shown in the pic.
Thanks again
Click to expand...

That orange wire won't have any juice in it, it is a wire to feed juice into acc circuits in the fuse panel. Pick out a wire that come from the fuse panel designated for something you are not using. Make note of it on panel ID and fuse appropriately for the start circuit.
 
rich b, I’m going to you use the radio power wire on pin 30 since I won’t be running a radio. I’ll be sure to fuse it. Earlier you mentioned a ballast resistor on the coil circuit; if I’m running a ballast coil would you still recommend adding a ballast resistor? Thanks again I really appreciate your help. Tony
 
You must log in or register to reply here.
Back
Top