Why does the wiring diagram contradict the shop manual on Starter wiring on 48 DeSoto?

[MarcDeSoto]

As you know from my previous post on my starter, when i installed it and connected the remote start switch to the upper right terminal, the wires on my remote start switch got hot and the starter didn't crank.  When I took it in the electric shop, they said I was connecting the switch to ground!  But it always worked before when I connected it there!  And I just checked the shop manual covering 46-50 DeSoto and it shows the push button start switch connecting there.  Check my video of the blown up wiring diagram that I made.  But on the blow up of the starter in the manual, it shows the upper left terminal on the solenoid as being the solenoid switch.  The wiring diagram shows that terminal going to generator!  Did DeSoto change the solenoid wiring during production of the S-11?  

 

 

[Sam Buchanan]

Who knows....just connect it so it works. 

[Dodgeb4ya]

The way to correctly hot wire your starter to work...

***Upper small left stud jumper to block (ground). Normally connects to the "ARM" stud on the generator.

***Upper right outer small stud connects to starter button or your starter remote button.

This is the way I have cranked over many many 1941 -50 Chrysler and DeSoto's.

All those square box solenoids are wired and operate the same...all of them....yes all.

 

[Dodgeb4ya]

If it doesn't work ..the solenoid has been electrically wired different internally.

Do what ya gotta do....connect so it cranks like Sam said..

[MarcDeSoto]

That's what I thought and that's the way I always connected it in the past.  But after they rebuilt my solenoid switch, I connected the remote starter swtich as you say and got short circuited!  The wires got smokin hot and no cranking!  Did you see the blowup of the solenoid above.  It contradicts the wiring diagram with the solenoid switch on the upper left.  And that's how my solenoid was rebuilt with the switch terminal on the left.  

[Dodgeb4ya]

Your wires 29 and 27 in the wiring schematic are correct.

The starter and solenoid picture you posted is correct too for 1946-48 DeSoto too.

[vintage6t]

IMO I don't think the manual shows anything regarding wiring. It is simply showing the the "solenoid switch" unit/assembly.  Similar to all the other parts in the diagram.

[MarcDeSoto]

Yes, now I see that.  It's just pointing to the whole solenoid as the switch.  I guess now I should just reverse what goes to those two terminals, with the generator now going to the upper right terminal.  

Edited March 25, 2023 by MarcDeSoto

[vintage6t]

 I could be wrong about this but I think the side of the soleniod the goes to the generator is the ground. But it's only the ground when the engine is not running. Once the generator starts producing voltage that generator terminal probably goes to 6 volts. That would prevent you from engaging the starter when the engine is running because there would no longer be a path to ground.

[harmony]

3 hours ago, vintage6t said:

 I could be wrong about this but I think the side of the soleniod the goes to the generator is the ground. But it's only the ground when the engine is not running. Once the generator starts producing voltage that generator terminal probably goes to 6 volts. That would prevent you from engaging the starter when the engine is running because there would no longer be a path to ground.

Quite correct.  I just went though this whole process with the solenoid on my spare engine. ( In a fairly recent thread) I couldn't figure out why it wouldn't work as a bench test.  The reason was that I had to manually ground that post. because I wasn't connected to the Generator on the bench. 

[joecoozie]

When you brought it back to the shop and they showed you the starter "working" on the bench, did you watch and take note how they connected the wiring to get the starter to spin?

It seems like, from what you describe, the internal wiring on the solenoid may be reversed?????

[MarcDeSoto]

Yes, the specialist who rebuilt my solenoid reversed the wiring for those two upper terminals.  I don't know if it would be an easy job to reverse the reversal, but the starter works now.  The battery cable still goes to the big lower right terminal.  

[Dodgeb4ya]

In the solenoid starter picture...

The "Solenoid Switch"arrow points to the grounding inner stud...that doesn't mean that stud is the starter switch terminal.

The arrow should have generally just been pointing to the solenoid box cover.

Indicating here is the solenoid switch assembly.

They should not have reversed the grounding and starter switch terminals. Silly boys.

Edited March 26, 2023 by Dodgeb4ya

[vintage6t]

According to the diagram, technically on the two upper terminals on the starter there is no such thing as "backwards". You can see in the diagram 1 and 2 are isolated from the rest of the relay circuitry. Those terminals are for the internal relay that close the relay points 3. The relay will work the same regardless of which of its internal coil wired are on 1 or 2. My point is that the repair shop can't really wire it internally for positve or negative. It doesn't matter. The internal terminal connections are dictated by the physical layout of the relay and the length of its coil wires.

 

Externally it also doesn't matter if the car's starter wire is on 1 or 2. The ground to the generator will simply just go on the opposite terminal. 

 

Now when you use a remote starter, you better know which terminal is wired though the car's harness to the generator's A terminal and which is to the car's starter switch. One side of the remote starter switch has to go on the same terminal as the car's starter switch. The other side of the remote switch to chassis ground. Otherwise if the remote is connected to the gen A terminal, instead of the car's starter switch side, of the soleniod you'll get a direct short to ground when you push the remote button.

Edited March 26, 2023 by vintage6t

[MarcDeSoto]

I have never connected one wire of my remote starter switch to ground.  One wire goes to the NEG battery post and the other to the solenoid switch.  Will it really work that way?  

[Sniper]

2 hours ago, MarcDeSoto said:

I have never connected one wire of my remote starter switch to ground.  One wire goes to the NEG battery post and the other to the solenoid switch.  Will it really work that way?  

 

If that schematic is correct, no.

 

The ground isn't switched the supply is (-6v in your case).

[vintage6t]

3 hours ago, MarcDeSoto said:

I have never connected one wire of my remote starter switch to ground.  One wire goes to the NEG battery post and the other to the solenoid switch.  Will it really work that way?  

You're correct. What I meant to say is if you connect the starter switch to the solenoid terminal that is grounded via generator terminal A and the other side to battery Neg, you'll get a direct short when you press the button. The point is to properly use a remote switch you need to know which side of the soleniod is attached to the car's starter switch and attach it there.

[MarcDeSoto]

Yes, I know all about that short circuit since the guy who rebuilt my solenoid switched terminals on me!  Engine starts right up and is running great right now.  Check out my other recent post.  

[wagoneer]

Okay? So I replaced my generator with an alternator; no A terminal anymore - where does that wire go now? And is that A terminal wire the same post as the the starter wire? And the. The top left post is wired to negative terminal (hot)?! I don’t see that in the Chrysler wiring diagram which is like your desoto wiring diagram.

 

 

my solenoid wasn’t going until I connected top left to engine ground . Do I have mine wired backwards?! 

[DonaldSmith]

You were correct to connect from the top left of thesolenoid (as looking at it from the front) to a ground at the engine.    

Ma Mopar grounded the solenoid through the generator so that when the engine was running the generator's emf or whatever counteracted the ground, to keep the starter from cranking when the engine was running.  

As I recall from when I installed my alternator, I grounded the upper left solenoid post.  I abandoned the red wire that led to the generator A post.  I conected the green wire that went to the F post of the generator to the post of the alternator.  I bypassed the regulator, and connected the other end of the green wire to the black wire that had been connected to the regulator.