When my starter switch went bust this past week, I decided that as long as I'd have to take things apart to install a new one, I might as well take the opportunity to update the system with a solenoid. -Unfortunately, the solenoid didn't come with directions and I'm not 100% sure how to hook it up.
Below is a photo of my broken starter switch, hooked up as it was when I bought the car.
Brown wire "A" runs to the terminal block under the hood.
Yellow-tipped, Black Wire "B" runs to the rear of the car and I don't know where it terminates.
Black Wire "C" runs to the brake-light switch.
Cable #1 runs to the starter.
Cable #2 runs to the battery-disconnect switch and then to the battery.
Below that is a photo of the solenoid. -
A tiny letter "S" is engraved into the plastic housing behind the terminal I labeled "5." -
A tiny Letter "I" is engraved into the plastic behind the terminal I labeled "6."
What I need is for someone to tell me, by referencing the numbers and letters, how to hook up the cables and wires. -If it matters, my car is a 1915 Touring with a retrofitted, electrical system (and the alternator, starter, battery, headlights, brake-lights and turn-signals are all 12-volt units).
Cables 1 and 2 go to solenoid 3 and 4 respectively although 3 and 4 can be reversed for convenience if necessary. Wires AB andC still go to cable 2 connection. Treminal 5 on the solenoid goes to one side of the starter button and the other side of the starter button goes to Batt + which can be the same terminal as cable 2. You don't need terminal 6 on the solenoid.
Chuck is correct but one detail must be noted. You must also ground the mounting point of the solenoid if you don't bolt it directly to the frame.
I hide a small normally open push button switch on my cars. The floor button is not a good switch unless it is an original one.
You can still use the floor button, but now it will fire the solenoid.
The 4 terminal switch does not have to be grounded by the mounting bracket. The 2 small terminals complete the circuit to close the switch between the 2 large terminals. The 3 wire type Ford solenoid, with a single small terminal and 2 large ones, must be grounded through the mounting bracket because power to the small terminal completes the circuit through the mount/ground. #3 & 4: batt in & starter out. #1 & 2: ground and power. You can either A: permanently ground one small terminal and use power to the other to operate it OR B: permanently power one and use a grounding switch to operate it. Your choice as to how you hook up the small ones. The large ones MIGHT have one side marked Batt.
The OP said the small terminals are marked "I" and "S". On this type solenoid the "S" terminal is for energizing the solenoid and the "I" terminal is +12v. to temporarily bypass the ballast resistor to shoot full voltage to the coil during starting.
Sorry. That 1 & 2 should have read 5 & 6. Repeat: It doesn't matter how you hook up #'s 5 & 6. You must power one and ground the other to activate the coil that operates the solenoid. Ford used this solenoid in conjunction with the neutral safety switch to operate the starter. I believe the neut. safety switch provided the ground and the key provided the power.
What Chuck describes is what I remember from late 50's and on Fords. Not sure how long they continued that ballast resister setup.
When I put a solenoid like that on my speedster, I bolted it to the frame (for the ground) the "S" terminal to my starter switch and left the "I" terminal unused.
The top bolts that hold the steering column on the firewall can hold the sillynoid with a second pair of nuts and lock washers if they are long enough. I did that on my little pickup as I didnt want to burn up the good foot switch with the high current.
I like this system for you cant forget to bring the spark rod all the way up to start, damaging the starter
it can also be done with a micro suith at the spark rod in the engine compartment
The heavy bolts go to starter and battery
A little web search found this for the 12 volt solenoid. http://www.texastparts.com/mm5/manuals/T5014-S12.pdf
Thanks John !
I have 6 v., and with your idea found this...
(courtesy of Texas T)
Call me stupid if you want but I wonder how a solenoid is an up date to a simple system? Don't be to hard on me guys. KGB
I'm somewhat paranoid about the "simple system" starter button failure stuck in the on position and not having a wrench handy to disconnect the battery cable.
Plus, I don't mind folks sitting in my cars, and that heel operated starter switch unfortunately is in a "bad" position.
No, you're not stupid - I'm paranoid....
It really is just a complication but he seems determined.
It simply moves the current load from the original switch to a more positive contact. If you're a little light on engaging the original switch, the contacts will arch and burn. They have on occasion welded themselves together. A solenoid "slams" the contacts, within the solenoid, together in a few milliseconds and reduces the chance for arching.
The load on original switch is reduced from about 300 Amps to about 1 amp.
If you run the wire from #5 through a Packard start button on the dash, that will be a real upgrade.
I can't imagine why anyone would want to defeat the simplicity that made the Model T so famously reliable. If it took a century for the switch to die, that's a pretty good track record. Wouldn't it be better to just replace the switch? I have seen many solenoids die in a short time. When it happens on your T, you will now have to figure out if the problem is the switch or the solenoid.
(Message edited by 404 not found on November 13, 2014)
Well, Dave, the original switch is worn out.
Besides not wanting to put a heavy electric current through the iffy switch, there is the problem of accidentally jabbing the starter-button while the engine is running (there being very little room for my big, clumsy feet). _When that happens, it's pretty rough on the bendix and ring-gear. _Some guys have addressed this problem with button protectors made from empty prescription bottles and such. _That works, I guess, but it's kind of a makeshift, stopgap way of doing things and lacks elegance.
With the solenoid in place, I can hide a little starter kill-switch somewhere and it'll cut the floor-button out of the circuit so it won't matter if I accidentally step on it. _Then, if the car stalls in traffic, a simple flip of the little switch will arm the starter-button. _That solves the problem with style.
Well if stepping on the button is a problem, you gotta do something. That's never happened to me, I don't know why. I guess I should look and see just how close I am to stepping on it by accident.
Ford must have thought it wise to move it, (the starer switch) because when the Model A came out they did move it.
I also like to install a fuse or fusible link in all the circuits drawing current. It's a lot better than your pride and joy going up in smoke and wrecking your day.
To answer your question. I installed a solenoid to protect the original starter switch in my car. That is allot of amperage going through 88 year old (and for most older) contacts. I use the starter switch to trigger the solenoid so I don't damage the original switch from all that current. I also have heard that the reproductions switches aren't that great so I did what I thought best to keep the original switch in use.