Interior light mystery ??

[harmony]

My car is a 1948 Chrysler Windsor.  The rear right door activates the dome light in a conventional way with the plunger style push button on the door jamb. The front right door has the same button, but it doesn't activate the dome light even though the voltage goes to it first before it goes to the back door. I've checked for continuity and it's good from the front door switch to the back door switch and then on to the dome light. For whatever reason Chrysler decided to put a switch on the inside of the door post for the drivers side to activate the dome light, instead of the plunger switches on the door jambs. What's that all about?

 

Anyways, there is a switch under the dash and according to an illustration from the owners manual, when the front passenger door is closed and the switch is turned on, it bypasses the plunger switch on the door jamb and gives power to the wire going to the dome light. I tested it and sure enough that's what happens, but the dome light doesn't come on. I'm guessing that that's a way of having an interior light with all the doors closed. Even though that can be achieved by reaching over your shoulder and flipping on the post switch on the drivers side between the front and back door.

 

So since the bulb is working on the dome light and I have continuity everywhere, I can only assume my wiring is ok. Any ideas what's going on or why that switch is there under the dash? (switch is directly above hand brake in the  image)

 

Another somewhat related question is how do I turn on the two flat round lights under the dash at the outside corners? (left of that switch) I've tested the bulbs and they are both ok. But the wiring is too tight up under the dash and hidden to follow the wires. (yellow with black tracer)

[chrysleritis]

That switch is supposed to be wired so that you can dim or turn off the instrument panel lights. In one position, the instrument panel lights are off, in another position, they're dim, and in another position, they're bright. The instrument panel lights come on when you turn on headlights. Those courtesy lights under the dash there may be wired so that the left side is a flasher warning light that the parking brake has been left on, and the right side one should perhaps be connected in the circuit with the dome light. It may also be the case that those wires are not yellow with black trace, (which is more typically a fuel gauge or starter circuit color) but might have originally been red. Have you got the wiring diagram and manual?

 

[Frank Elder]

If your wiring is the original 71 year old loom then you shouldn't assume anything.

 

9 hours ago, harmony said:

 

 

So since the bulb is working on the dome light and I have continuity everywhere, I can only assume my wiring is ok. Any ideas what's going on or why that switch is there under the dash? (switch is directly above hand brake in the  image)

 

 

[greg g]

My car had two underdash courtesy lights. Don't know if they were d ealer option or owner installed.  They were wired hot from the battery side of the ammeter.  A door switch provided a connection to ground with the door open.  There was one bulb in each footwell.  They were independent from the dome light.  My dome light is operated manually by a slide switch on the passenger side door post.  Some where along the way the powered wire between the bulbs lost insulation and went to ground, there was no fuse in the line so the circuit basically melted down before I could find and cut the power wire.  Luckily, no other circuits were involved and nothing caught on fire.  The smell lingered in the car for nearly a year.  

 

If you decide to investigate, wiggle and tug etc disconnect your battery!!!

Edited August 26, 2019 by greg g

[chrysleritis]

[chrysler1941]

2 hours ago, greg g said:

My car had two underdash courtesy lights. Don't know if they were d ealer option or owner installed.  They were wired hot from the battery side of the ammeter.  A door switch provided a connection to ground with the door open.  There was one bulb in each footwell.  They were independent from the dome light.  My dome light is operated manually by a slide switch on the passenger side door post.  Some where along the way the powered wire between the bulbs lost insulation and went to ground, there was no fuse in the line so the circuit basically melted down before I could find and cut the power wire.  Luckily, no other circuits were involved and nothing caught on fire.  The smell lingered in the car for nearly a year.  

 

If you decide to investigate, wiggle and tug etc disconnect your battery!!!

You were lucky. Read about vintage car in another forum that burned down completely when headliner caught fire. 

Therefore one should always fuse dome light hot lead from head light switch, because one cannot rely on +70 years old thermal fuse.

Edited August 26, 2019 by chrysler1941

[Sam Buchanan]

This is why I often read threads that don't appear to apply to my P15. I purchased an inline fuse holder this morning for the courtesy light circuit....I really hadn't considered the consequences of a shorted wire behind the headliner.  ?

[Dodgeb4ya]

"Another somewhat related question is how do I turn on the two flat round lights under the dash at the outside corners? (left of that switch) I've tested the bulbs and they are both ok. But the wiring is too tight up under the dash and hidden to follow the wires. (yellow with black tracer)"

 

That little under dash switch only moves rt or left. No middle position.    It only turns on the passenger side lower under dash courtesy light. That's all that switch  does.

The drivers side under dash light will only blink on and off indicating the Emergency brake handle is pulled out...this happens only when the key is on...it lights up at no other time. It's only a warning light for the e-brake.

There is no dimming of the dash lights.....they are only turned on after the head light switch is pulled out and then the "Panel" light knob pulled out. No bright or dim...just on.

The yellow with black tracer wire is the dome light and switch wiring circuit color... A Red always "hot" 6 volt wire feeds from the back of the HL switch to one terminal of each door switch and the under dash switch.

Edited May 13, 2020 by Dodgeb4ya

[chrysler1941]

1 hour ago, Dodgeb4ya said:

"Another somewhat related question is how do I turn on the two flat round lights under the dash at the outside corners? (left of that switch) I've tested the bulbs and they are both ok. But the wiring is too tight up under the dash and hidden to follow the wires. (yellow with black tracer)"

 

That little under dash switch only moves rt or left. No middle position.    It only turns on the passenger side lower under dash courtesy light. That's that switch  does.

The drivers side under dash light will only blink on and off indicating the Emergency brake handle is pulled out...this happens only when the key is on...it lights up at no other time. It's only a warning light for the e-brake.

There is no dimming of the dash lights.....they are only turned on after the head light switch is pulled out and then the "Panel" light knob pulled out. No bright or dim...just on.

The yellow with black tracer is the dome light and switch wiring color... A Red 6 volt always hot wire feeds from the back of the HL switch to one terminal of each door switch and the under dash switch.

It's interesting to see how they changed function of this little switch. On my 41 and later 46-48 it was called Instrument panel light switch, Where you could turn of all instrument, glove box, ignition key light, etc to avoid reflections on darker roads. 

Dome lamp switch was simply turn knob from dash or door switch called Reading light, and wired direct from head light switch.

[chrysler1941]

1 hour ago, Sam Buchanan said:

This is why I often read threads that don't appear to apply to my P15. I purchased an inline fuse holder this morning for the courtesy light circuit....I really hadn't considered the consequences of a shorted wire behind the headliner.  ?

Yes it was a 37 Cadillac burned down. He gave up on vintage cars. Sad story.

 

Although my wiring are new, have also fused stop light switch that is fed from the same head light switch and horn relay and cigar lighter fed from ammeter. They are all hot. One can't install enough fuses.

[greg g]

I have powered my brake lights all three with 55 watt halogen bulbs, from a new wire  with fuse from the battery side of the solenoid.  Takes a lot of load off those circuits that share the ammeter feed. Seems safer to me.

[Sam Buchanan]

4 hours ago, greg g said:

I have powered my brake lights all three with 55 watt halogen bulbs, from a new wire  with fuse from the battery side of the solenoid.  Takes a lot of load off those circuits that share the ammeter feed. Seems safer to me.

 

I have a Signal Stat turn signal switch which has fused power supply. Since the brake lights are powered by the signal switch I'm thinking they are protected now.

Edited August 27, 2019 by Sam Buchanan

[greg g]

My signals and brakes are separate circuits and fixtures.

[harmony]

6 hours ago, Dodgeb4ya said:

"Another somewhat related question is how do I turn on the two flat round lights under the dash at the outside corners? (left of that switch) I've tested the bulbs and they are both ok. But the wiring is too tight up under the dash and hidden to follow the wires. (yellow with black tracer)"

 

That little under dash switch only moves rt or left. No middle position.    It only turns on the passenger side lower under dash courtesy light. That's that switch  does.

The drivers side under dash light will only blink on and off indicating the Emergency brake handle is pulled out...this happens only when the key is on...it lights up at no other time. It's only a warning light for the e-brake.

There is no dimming of the dash lights.....they are only turned on after the head light switch is pulled out and then the "Panel" light knob pulled out. No bright or dim...just on.

The yellow with black tracer is the dome light and switch wiring color... A Red 6 volt always hot wire feeds from the back of the HL switch to one terminal of each door switch and the under dash switch.

So when you say "passenger side lower under dash courtesy light"  I'm assuming you mean the same light as in my photo, only the one on the far right under the dash, same location opposite end of under dash, correct?

To be honest I never looked at that light once I had the key turned on and before I released the hand brake.  I haven't driven the car in the dark yet so perhaps that light might make itself obvious at that time without looking down there.  I'll have a look later on tonight. Like I said I tried to follow the wire coming out of the socket but it's neatly tucked up and only goes a couple inches before it enters the loom. Somewhere along the way I suspect it has to go to a flasher, correct?  Is there a switch coming off the hand brake somewhere?

[harmony]

9 hours ago, chrysleritis said:

Thank you for this wiring diagram.  I have it in my service manual, but thanks anyway,

[harmony]

3 minutes ago, harmony said:

So when you say "passenger side lower under dash courtesy light"  I'm assuming you mean the same light as in my photo, only the one on the far right under the dash, same location opposite end of under dash, correct?

To be honest I never looked at that light once I had the key turned on and before I released the hand brake.  I haven't driven the car in the dark yet so perhaps that light might make itself obvious at that time without looking down there.  I'll have a look later on tonight. Like I said I tried to follow the wire coming out of the socket but it's neatly tucked up and only goes a couple inches before it enters the loom. Somewhere along the way I suspect it has to go to a flasher, correct?  Is there a switch coming off the hand brake somewhere?

In that wiring diagram that chrysleritis posted I see a "hand brake light switch" where would that be on the car?  I also see that one of the wires from that switch goes to the turn signal flasher.  So I guess that answers one of my previous questions.

[harmony]

13 hours ago, Frank Elder said:

If your wiring is the original 71 year old loom then you shouldn't assume anything.

 

 

I'm amazed at the wiring under the dash.  It looks brand new. Nothing at all is disturbed and only a slight bit of dust.

[harmony]

11 hours ago, greg g said:

My car had two underdash courtesy lights. Don't know if they were d ealer option or owner installed.  They were wired hot from the battery side of the ammeter.  A door switch provided a connection to ground with the door open.  There was one bulb in each footwell.  They were independent from the dome light.  My dome light is operated manually by a slide switch on the passenger side door post.  Some where along the way the powered wire between the bulbs lost insulation and went to ground, there was no fuse in the line so the circuit basically melted down before I could find and cut the power wire.  Luckily, no other circuits were involved and nothing caught on fire.  The smell lingered in the car for nearly a year.  

 

If you decide to investigate, wiggle and tug etc disconnect your battery!!!

Good advice.  It's difficult to determine what's fused and what's not and what's live and what's not.

[Dodgeb4ya]

My 48 Chrysler also has mint bright colored wiring too.. will never touch it. It's fine. 

I have installed quite a few new RI and Y&Z harnesses in the 46-48 Chrysler's that needed new wiring to be safe.

E Brake Switch shown 1946-48 Chrysler

Edited August 27, 2019 by Dodgeb4ya

[harmony]

I found that switch on the hand brake.  But it was getting dark here so hopefully tomorrow I'll get out my multimeter and perhaps there is a bad contact or something like that, that is causing that light not to flash when the ignition is on and the brake is applied.

I appreciate all the thoughts and suggestions.

[chrysler1941]

It's good advice to disconnect battery when checking wirings.

 

For measuring, it's easier with power on, so after disconnecting battery cable, I use a small lead with 15A  fuse with alligator clips on both ends . In case of shorts, only fuse burns. 

[christianad1156]

The switch that you mention that is on the drivers side, near the steering wheel that only moves left and right is the map light switch.  The passenger side, round light pointing down is the map light.  The switch controls the map light and nothing else.  The map light can also be turned on when the passenger front door opens with the automatic door jamb switch.  The map light switch does not dim the instrument lights.  The instrument light switch does that.  I believe if you pull it out there are a couple setting or you can twist it.  Its been a little while and unfortunately I'm away from my car right now or else I'd go check.

 

The dome light can be turned on by the rear doors opening with the switches in the rear door jambs.  There should be another switch on the B pillar that controls the dome light manually which matches the wiring diagram "pillar" switch.  

 

The switch that operates the hand brake light is located near the handle for the hand brake.  As the hand brake moves, it pushes on a plunger depending on what position it is.  There are two wires that go that that switch from the dash harness but the switch isn't meant to be controlled by anything other than the hand brake handle.  Its powered through the flasher because it will flash when ignition is turned on but the hand brake engaged.  The hand brake light is the round light on the driver's side.

 

I hope this answers your questions.  I have the drawings for the wiring including colors and size.  The drawings in the shop manual and other's I've found don't actually show the location and physical locations of the wires in the harness like the drawings do.  I also just happen to have a dash harness pulled from a junkyard car sitting in a room waiting for me to put away.  

 

If you ever need wiring for these cars, I recommend you consider RI Wiring.  They make great products to the exact specifications of the originals.  I went to their shop once and the guys spend plenty of time answering my questions and showing me around.  It was real treat for me. 

 

Christian 

[Dodgeb4ya]

There is no way to dim or brighten the 1946 to 48 Chrysler dash lights.

Just pull "Panel" knob out to turn the dash lights on. Push it in to turn them off.

This after first first pulling the "Head" light switch knob out.

Rhode Island as mentioned is the best harness for the 1946-48 Chryslers. They have built so many of them that they have the proper different versions depending on production date and models. Y and Z wiring needs parts of their harnesses cut and redone to make them right.

This up till a year and a half ago. I had this issue on a 1948 NewYorker 3 passenger business coupe resto job.

[Aram]

I have a 1947 Chrysler Windsor. Can’t figure out how to pop the dome light off to check the bulb. Don’t wanna break anything. Any advice?

[christianad1156]

Aram,

 

I hop you got your dome light off by now.  But just in case, to take it off, you just have to pull hard.  I can take a few photos if needed, just let me know.  Its held in place by little metal tabs that go over raised metal "dots."  Not a great description I know but the stainless steel oval and glass just pulls off.  A little wiggling should help.