I've decided to review and clean / replace much of my electrical system. I have a new battery, new starter solenoid and starter switch.
Per some recommendations on this forum, I also replaced the ground strap (new braided heavy duty to frame). And I replaced all the battery cables to 1 gauge (it was all #2 gauge).
Everything seems ok except that the switch doesn't seem to work properly. I've attached photos of the starter switch, the tangle of electrical beneath the seat, and a drawing of my basic schematic in very non-electrical format.
I have voltage in all the places I think I should. Except when the switch is installed. For instance, power at the battery switch is fine. When I touch the thin wire from the post on the solenoid directly to power at the battery switch, it does it's job - solenoid clicks and starter begins to turn. However, when I put the starter switch in the mix, nothing. I'm not sure what's up with the switch (marked momentary switch on the drawing). But suspect it's the "nut behind the wheel". My switch has one wire to the solenoid and one to ground. It seems to me that there should be some power in the mix, but this is how I'm pretty sure the old switch was wired up. Also matches instructions on the solenoid installation.
I'm hopeful that this is a very simple answer - maybe check the muffler bearings?
Note about the wiring - Some of the "extra" stuff in there is from the switches for the lights / turn signals that are temporarily pulled out.
Connect the momentary switch to a battery source. The solenoid gets its ground from its mounting to the car frame.
Thanks John. I wondered about that. The solenoid is screwed into the wood frame next to the gas tank, so not grounded. However, I did run a dedicated ground wire from the screw holding the base down to the grounding strap bolt on the frame by the battery. Solves the solenoid ground issue.
Would the battery source for the starter switch come directly off the switched hot post on the battery switch?
And for my general knowledge, I was mimicking the previous setup but also following the instructions from the Texas T solenoid installation. (see below)
In your initial post you stated " When I touch the thin wire from the post on the solenoid directly to power at the battery switch, it does it's job - solenoid clicks and starter begins to turn."
This tells us your solenoid requires a battery voltage not ground to operate. There are solenoids that are built to require battery and some are build to use a ground to operate. So just disconnect the ground from the switch and connect the switch to the battery side of the solenoid.
Makes perfect sense - THANKS!
What's forgotten is that's there's 2 types of these solinoids: the 3 terminal (2 lg. 1 sml.)can only be operated by + to the sml.terminal. The mount is the ground. The 4 terminal type (2 lg. 2 sml.) can be operated by + or - . The mount's not grounded and the 2 small terminals are the operating coil. Power one grnd. the other it works or vice versa.
Seeing all that makes me glad 3 of my 4 T's are crank start!
Since that is not an original type starter switch, I will refrain from commenting on the solenoid. However one safety item I would like to discuss. If there are any sparks on any of those wires near the gas tank and fumes from gas, such as overfill at the gas station with spillage, or splash around the filler cap you could have an explosion or fire. If it were mine, I would minimize the possibilities of sparks near the gas tank by moving that switch somewhere else.
Norman is so right, separate your electricity as far as possible from the gas tank. One spark can burn up your car.
If you use a battery switch, use a heavy duty one, not the plastic junk you can buy very cheap.
I should install the switch between the - post of the battery and the ground. Installing the switch that way you cut out all the electricity when you set the switch on OFF. In your drawing you only switch off the starter circuit.
Since a Model T doesn't use a solenoid, why is it that you think it should have one? They work just fine the way Ford made them! All you are doing is adding more stuff to have problems with!