Headlight switch - 75 Duster - Stumped...

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SalC

SalC

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Attached is a picture of my old headlight switch and the new one. I've rewired the entire car using the EZ Wiring harness and everything has been great so far. But I'm stumped on the headlight switch. I ordered a new one and everything looks the same.

My problem is I can't get any power out to the parking lights. I've rung out the power in (12v) to the the headlight output when the switch is pulled out all the way and no problems there, I get output to the headlights and they work. But I don't have any output to the parking lights terminal. Even when the switch is pulled halfway I get no output to the parking lights. Tried to ring it out and no continuity. The old switch is the same way, no continuity to the parking lights terminal so this tells me it's not the new switch that is bad. Tried all the other terminals on both switches and nothing. Am I looking at this incorrectly? Also nothing out to the dash lights either.

I'm stumped!

Duster Headlight Switches.jpg
 
the terminal on an angle ( marked P) is the output for your park lights. The one marked H is for your dash lights
 
eeka440 said:
the terminal on an angle ( marked P) is the output for your park lights. The one marked H is for your dash lights
Click to expand...

I don't think that can be. Terminal P supposedly isn't used and when I ring it out from B1 to P I get no continuity either. The terminal marked H is only on (continuity) when the knob is pulled all the way out, hence it's for the headlights.

Here's a photo I found when searching for the pinout on the internet, it's what I followed to wire the switch but when I check for continuity I only get an output to terminal H (headlights) and nothing else. The only other terminal that did checked out was D which is used for the dome light, that terminal has continuity to ground when the switch knob is turned completely counter clockwise which makes sense.

I have to be doing something wrong because both the new and the old do exactly the same thing and the old one worked before I ripped all the wiring apart.

HeadLightSwitchJumperNotes.JPG
 
Doh! I got it.

Terminal B2 (battery 2) is a separate 12v input, from a fused source. When I check continuity from B2 to R (parking lights) and also B2 to I (dash lights) with the knob pushed in (off) they are open, however when the knob is pulled out to the parking light position and the headlight on position I get continuity from B2 to both R and I.

I wasn't using a separate 12v source for them...

Never mind :)
 
2 separate power supplies instead of a jumper B1->B2, So you could have a catastrophic failure in all the smaller lights and retain the headlights, or vice versa. Smart.
Completely separate circuits/bulbs for brake and rear turn ( turn signal switch cannot interrupt brake lamps ) is smart also. This is very common in newer vehicles but quite rare for the classics.
Anyway... happy motoring.
 
I have an EZ wiring harness and I'm currently wiring my switch also. My P terminal has power in park lights and then shuts off with headlights. Is that used for anything?
 
This post is an EXCELLENT example of why you should run directly to the factory service manual
 
SalC said:
Doh! I got it.

Terminal B2 (battery 2) is a separate 12v input, from a fused source.
Click to expand...

Also, you can hook the parking lights to the tail light terminal and have "full time" marker / tail lights

Another "diddle."

Your dash lights are a "bit of a trick." The are also supplied from B2, so the tail/ park circuit must work so that the dash lamps can work.

Originally, the output of the dash dimmer went TO the fuse panel "inst" fuse on a tan wire, so that is the only fuse that is "after" the switch
 
67Dart273 said:
This post is an EXCELLENT example of why you should run directly to the factory service manual
Click to expand...
I have a 74 Valiant wiring diagram that I was using but the post locations were different. Also I had a 3 speed wiper switch and motor vs the 2 speed shown. I love having the wiring diagram but when there is differences from my vehicle I come search here and have always found the help I need:)
 
Well what are you using?

The closest is the 73 factory manual at MyMopar (which came from the guys here)........and I did a terrible scan of the 76 wiring diagrams which you can download, let me find it............

Free service manuals

73 shop manual

Free service manuals

And the 76 wiring diagrams. All I had was a paper 76 shop manual

Free service manuals

http://www.letsgocomputers.com/docs/76wiringAbody.pdf

In the 76 pdf the light switch diagram is map 47B, page 25 of that pdf

Notice it says "CI35" which is Connector, Interior, 35. That is page 46 of the pdf


...............That might not be much help

In the 73 shop manual, the light switch diagram is map C10 on page 8-156, it is called "CI2" here which is shown on page 8-167, here it is

CI2.jpg


Yeah, see the stupid thing is looking into the face of the connector so it's "mirrored." THIS and the 72 below is looking "down at" your light switch holding in your hand

72headmirror.jpg
 
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Here is the switch out of the 72 manual, I bet it's the same....

72head.jpg
 
Notice the "P" (parking) is not used. Ma hooked the parking lights to the tail light circuit to keep them on. Yellow is the ground for the dome light AKA "twist the knob" to the left

Tan is the output of your dash lamp dimmer

Green is the headlight output going to the dimmer

You already know B1 is main power to headlamps, B2 is "the rest"
 
67Dart273 said:
Notice the "P" (parking) is not used. Ma hooked the parking lights to the tail light circuit to keep them on. Yellow is the ground for the dome light AKA "twist the knob" to the left

Tan is the output of your dash lamp dimmer

Green is the headlight output going to the dimmer

You already know B1 is main power to headlamps, B2 is "the rest"
Click to expand...
How do I find out what feeds B2? I try not to bother you guys but.....
 
OK look in the factory service manual. You are going to have to buy one, used, repop, on CD, etc. The latest one you can download for free on MyMopar is a 73. There are differences, but that part of the circuit may be the same

I can tell you that ONLY the headlights is fed UNFUSED from the ammeter circuit, and there's a breaker on/ in the light switch itself

The other circuits are all fed off a fuse in the panel

The dimmer controlled dash lights are a trick. They RECEIVE power from the B2 circuit at the switch, through the dimmer control, and out TO the fuse box and TO the inst fuse and then off to the various dash lights
 
Understood. I'm just thinking ( possibly wrong, of course) no power tan wire coming from the headlight switch, that I need a switch? The 20 amp for the taillights is good . Is the breaker in the switch accessible? Much appreciate your knowledge and time!
 
Ironracer. I just posted this in another thread because I got confused with where I saw you most recently tacking on to an older thread. My advice is to start your own thread.
Take your time typing it out, and edit as needed to make it easier on everyone trying to help.

If you want to reference older threads, hover your mouse over the post number, right click on the post number and select copy.
Then paste that in your post.

For example, this is a link to a post I recently made with description and sketch of the headlight switch wiring.
No power lights etc but ignition turns over?

To find out where wires come from or go on the electrical diagrams, look at the code on the wire.
So looking above at the headlight connector, if it was a '72 or a 73, you're asking about the wire connecting at B2.
What's that identified as?

L8 18P

L is Lights related. 8 is the 8th wire they labeled. 18 is 18 gage. P is Pink
If you can look at your connector make sure it looks like the book says. (Sometimes there are goofs or changes since the diagram was drawn.)
Then look on the diagram for where L8 connects.
It almost certainly connects to the hot side of the fusebox. Whether directly or through some other wire, I don't know off hand.
You can look at the '73 book for now and when you get your hands on '74 FSM see if there was a change.

If you have the fusebox down, you can look to see if the 18 ga pink wire goes to the back of the fuse for the park, tail lights. You can't see the wire connection from the fuse side.
 
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Ironracer said:
Understood. I'm just thinking ( possibly wrong, of course) no power tan wire coming from the headlight switch, that I need a switch? The 20 amp for the taillights is good . Is the breaker in the switch accessible? Much appreciate your knowledge and time!
Click to expand...


OK, you "should" have started your own new thread. So, what does NOT work exactly?

Here once again is the breakdown. B1 is headlights ONLY power TO the switch. Do the head lights work? then forget about that part

B2 / park/ tail/ dash lights ARE A SEPARATE SWITCH completely "in the same box"

B2 is powered from a fuse and is hot at all times. Obviously, park is only hot in the park position. On that 74 P should not be used. Both the park and tail come off the tail lamp connection, so they are both on with either "park" position or "full on" position

The tan is the dash light dimmer OUTPUT from the switch and is hot ONLY

with the switch in either park or headlights
with a good fuse supplying B2, so the park/ tail lights must be working
with the dimmer control turned "left" for brighter dash lights

That tan then feeds TO the INST fuse in the fuse panel and from there out to all dash lights
 
Mattax said:
Ironracer. I just posted this in another thread because I got confused with where I saw you most recently tacking on to an older thread. My advice is to start your own thread.
Take your time typing it out, and edit as needed to make it easier on everyone trying to help.

If you want to reference older threads, hover your mouse over the post number, right click on the post number and select copy.
Then paste that in your post.

For example, this is a link to a post I recently made with description and sketch of the headlight switch wiring.
No power lights etc but ignition turns over?

To find out where wires come from or go on the electrical diagrams, look at the code on the wire.
So looking above at the headlight connector, if it was a '72 or a 73, you're asking about the wire connecting at B2.
What's that identified as?

L8 18P

L is Lights related. 8 is the 8th wire they labeled. 18 is 18 gage. P is Pink
If you can look at your connector make sure it looks like the book says. (Sometimes there are goofs or changes since the diagram was drawn.)
Then look on the diagram for where L8 connects.
It almost certainly connects to the hot side of the fusebox. Whether directly or through some other wire, I don't know off hand.
You can look at the '73 book for now and when you get your hands on '74 FSM see if there was a change.

If you have the fusebox down, you can look to see if the 18 ga pink wire goes to the back of the fuse for the park, tail lights. You can't see the wire connection from the fuse side.
Click to expand...
Ok. I prowl through here researching all the time but I try not to bother anyone. Hence the old posts. My apologies
 
No need. It just helps avoid confusion. I tend to skim through stuff and at some point realize "old" and then somehow miss the split between "guy 1" and "guy 2" lol
 
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