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MikeC5

12 V system ground on starter switch?

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Can anyone take a look and see if/where the ground on the starter switch goes? The MIM schematic does show a ground and my car had it grounded but it didn't look like original wiring. Also, the wiring harness I bought has everything except a wire for this ground. Coincidence?

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When I took my switch off a couple of years ago, it did not have a ground wire attached. It only had the four wires as shown on pg 70.

Roland

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Mike, I checked my '25 by looking in at the back of the switch from the passenger side engine compartment. The smaller, top terminal on the passenger side has a tiny steel ground strap going over to the small slotted housing screw, shaped like the letter "Z". That terminal also has a pencil sized ground strap which is insulated, going down to the bell housing, about 12 or 14 inches long and fastened there with a 7/16ths" hex screw. If you take out the center wood floorboard strip, the hole for the ground strap should be staring you in the face, in the bell housing. Best regards, Pete.

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Hi Pete. Thank you for the details. Is your car using a positive or negative ground? On my car, the start switch terminal on drivers side (upper) is the one labeled ground. The terminal on passenger side connects up to ammeter/generator. Any chance you can get some photos?

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Mike, I have a lousy view here of my starter switch, in place, viewed from the driver's side engine compartment. I would think this mostly all original car still has the 12 volt positive ground system, I'm still far from getting it running, I still have all the fuel system off. I did connect up my battery charger to the battery cables at the battery box, (12v. pos. ground), and checked the wiring out, all lights work and stop light works. The newer looking "red" wire at starter switch box is that ground cable we were talking about that goes down to the bell housing.

Edited by Pete K.
second photo (see edit history)

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Mike, I edited my last post to include a drawing I made of the back of the switch. I hope you saw it. ---Pete.

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Thank you for the sketch Pete. I'll compare it to mine. I sent an email P-D, thanks!

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Interesting. My switch has the ground and indicator terminals reversed from Pete's sketch. This the diagram Gary sent me.

post-74074-143138969098_thumb.jpg

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Now this is very interesting! I double checked my drawing and it is not only correct, but the printed labeling I wrote on the diagram is actually stamped into the steel backing plate on my starter switch at each of the terminals. I traced all the wires from the switch and all are where they belong. All I can assume is my Dodge has had a "switchectomy" somewhere along the lines with an unknown Dodge Brothers foot switch. I cannot seem to see a model number on the switch body, difficult to find when I'm not sure even where to look for it.

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According to the mechanics information manual there were several version of the starter switch use, with different terminal locations. Here's some extracted text:

"The type 8100-A starting switch and cut-out was used from car 559,652 to car 728,303. It is exactly similar in construction except for a change in the location of the terminals...the battery and generator terminals are changed about, on this type switch, so that the wires do not cross...the terminal is grounded to the switch case, and to the steering column by a metal strap, instead of to the vacuum tank bracket by means of a wire, as in the type 8100 switch.

The type 11865-A switch was used from car 728,303 until the six-volt electrical system was installed on which the 15850 cut-out and 15380 switch is used. The 11865-A switch differs from the two previous types in that the series and shunt windings are not combined, and the contact points are made of metal instead of carbon. The ground terminal has been changed about with the indicator terminal."

Keith

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Thanks Keith, I missed those details in the MIM. I sounds like I'm safe grounding the switch at the (stamped in label) ground terminal.

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