1948 Chrysler New Yorker will not start with headlights turned on

[48 New Yorker]

My ’48 Chrysler New Yorker has a strange starting problem.  

 

The starter will not engage/crank when the headlight switch is pulled to on position -- I don’t mean slow cranking with lights on — it doesn’t crank at all…  with the lights on, pressing the starter button does not dim the lights.  With starter button depressed and lights on, the starter won’t engage — switch the lights off while depressing the starter button, and it fires right up…the headlight switch in the “on” position acts like a kill switch.

 

When the lights are off, it easily fires right up every time.  Battery is fully charged, battery cables are sized 2/0 (made from welding cables) and the generator has been replaced with a 6 volt alternator with internal voltage regulator — external regulator removed.  

 

Other than the headlight/starting issue, it starts easily and runs great.  Any clues?

[OUTFXD]

Perhaps the extra Power drain from the headlights  prevents the starter Solenoid from reaching appropriate voltage to switch on and  give power to the starter?

 

Also.  if you do replace the starter solenoid,  be sure it is with a 6v solenoid.   I went through three solenoids as the parts number kept being superseded with a parts number for a generic 12v solenoid,  which wont work in a 6v system.

Edited November 7, 2023 by OUTFXD

[plymouthcranbrook]

I expect your question is from idle curiosity as I can’t see a reason to ever try any car with an extra drain on the battery.  I don’t even like the modern cars that the headlights are the first thing turned on when starting.  Maybe someone in the distant past did a work around to stop a family member from doing this after tiring of having to go out on winter morning’s to jump start the car?

Edited November 7, 2023 by plymouthcranbrook

[Ivan_B]

I agree, this sounds like some custom wiring... Did you already have a chance to check your headlight switch wiring against a factory diagram?

[Doug&Deb]

Is it possible that a wire is shorting when the switch is pulled? My Coronet used to stall occasionally when the M6 down shifted and I was able to restart it with the lights on (not a good idea I know) . I’d check the wires to the switch first.

[Los_Control]

I have the feeling your car has been rewired over the years, not still the original cloth wiring the car was born with.

Off the top of my head, I'm thinking that there was some creative wiring done when it was rewired ..... If it was intentional or not, I have no idea.

 

Just using a modern ignition switch as a example. You turn the key on and it powers up the vehicle .... you twist the spring loaded switch further and it sends power to the solenoid using the "trigger wire" ..... Once started, the trigger wire never gets power again until you once again twist the key to start it.

 

The push button that activates the trigger wire on our old vehicles works the same way. ...... For whatever reason, when your headlight switch is turned on, the power is removed from the solenoid. ..... I would have to look at a wiring diagram to see where the power to the solenoid comes from ..... then look at your wiring to see where it is coming from.

 

It should not in anyway be connected with your headlight switch .... I think headlights and solenoid should be on different circuits not related to each other.

[Sniper]

Looking at a 47 Chrysler schematic, the ammeter has three connections on the battery side,  One is to the battery, one is to the ignition switch and the last is to the head light switch.

 

The feed from the ammeter to the ignition switch feeds the starter push button (key in run), which then feeds the starter solenoid and engages the starter when the button is pressed.

 

I do not see how the head lamp switch is int he circuit at all, miswire I suspect, assuming the 48 wiring is the same, I don't have a 48 schematic.

[48 New Yorker]

Lots of reasonable possibilities, which I will pursue. 

 

Plymouthcranbrook, you are correct, the issue is a matter of curiosity....while I'd rather not have the issue, I do enjoy the "detective work" to figure it out...  The wiring is original, and with one exception is stock....(previous owner installed a "rube goldberg" switch on the steering column to activate the backup light....light had been removed when I got it, but the switch remained. 

 

Sniper may be on to something.....in the distant past, I removed the ignition switch and may have mis-wired it on installation...usually don't make those mistakes, but the code stripes are very faded...will have to peel back some tape to trace. 

 

Also considering the effect of replacing the generator and voltage regulator with the alternator and built in regulator.  If I recall, there was a brown wire off of the generator/voltage reg. that prevented the starter from activating if the button was pushed while the car was running to prevent starter grind. 

 

[Hickory]

I also remember that my 49 starter solenoid was grounded through the generator to prevent it cranking while the car qas already running. This was advanced thinking by the Chrysler corporation. You now have an alternator so how has that been rewired. May be related may not.

[Bryan G]

Exactly what Hickory said. You can ground that terminal on the solenoid...when a ground is missing, automotive wiring will do really, really weird stuff! Components will find a ground in the strangest places sometimes. With my car, I had a bad start in the armature of my generator. The car would start fine, unless it happened to have stopped on that bad spot. My short term fix was to run a jumper wire to the cabin so I could ground it. Now I have an alternator and just grounded it permanently.

[48 New Yorker]

I agree with BryanG and Hickory....the search for the ground path thru the headlight switch begins. 

 

Here's my wiring diagram with the modification of the alternator.  Brown grounding wire from Gen has been removed from diagram. Highlighted in correct wire code colors, are the starting and headlight circuits.

Edited November 10, 2023 by 48 New Yorker
correction

[Hickory]

Just to eliminate that type of a problem i would just give the starter solenoid a permanent ground and see if there is a difference 

[48 New Yorker]

Several years ago when I switched out the generator for an alternator, I added several additional grounds between the block, body and frame.  I grounded the brown starter solenoid wire to the block, also ran a ground from the starter housing to the frame.  see photo.  Of course, now I have to be mindful not to accidentally hit the starter button when the engine is running or it will grind.

BTW, I attempted to start it w/headlights on while pressing the hi/low beam switch just to see if it made any difference....it didn't, still didn't crank.

[SteveR]

It sounds like your starter relay is somehow hooked up to your light switch. Using your diagram it looks like it should be hooked up to your ammeter. Does your ammeter move when you pull your light switch?

[48 New Yorker]

 The ammeter did register a discharge when the lights were turned on.

 

Think I found the issue.  While taking the above posted photo, I moved the brown grounding wire from the solenoid back and forth for picture clarity. Now the starter engages with the lights on....perhaps a corroded connection? I'll clean it up and hit it with some dielectric grease.  Thank all.

 

[Sniper]

Thanks for the follow up.

[48 New Yorker]

I'm guessing when the solenoid ground got wonky, it used the headlight switch in the "off" position for the ground....or just gremlins.

[Hickory]

I figured so, i like using star washers on grounds like that. It looks a little rusty maybe something to clean it and protect it. Glad you found it.