Wiring Issue Headlamp not working Continued...

[ricker4444]

So, I tested to make sure I had power going into Z. It looks like Y is the hot feed to headlamp and X is like a return. I have power on Z but no power coming out of Y. Does the power from the battery go directly to the bulkhead connector and then come out of Y to feed the headlamp or does it feed the switch first and then power the lamp?

 

[OttawaCharger]

Remember that your headlight has high and low beam. 2 separate circuits. So not a return. Both those are independent. There should be another page that shows the cabin side of the bulkhead. You can continue to trace your circuit inside the cabin.
As for a "Return path" Your ground is your return path in a DC circuit.

 

[67Dart273]

The headlight circuit is dead nuts simple. The headlight switch has TWO power sources. The headlights ONLY are powered from a tap off the "welded splice" in the ammeter circuit, to a built in breaker in the switch. With the light switch full on, it feeds headlights power out of the switch, down to the dimmer. TWO of the terminals of the dimmer are ALWAYS hot with the switch ON. One terminal is power coming from the headlight switch, and the other is that power, selected by the hi/ low function of the dimmer, to feed out through the bulkhead and to the headlights.

The proper description for the dimmer is SPDT or Single Pole, Double Throw. This means it is switching ONE circuit (single pole) and selects which of two outputs which it feeds to (double throw)

IF THE power is getting that far, your cluster bright indicator should light when you actuate the dimmer.

The high and the low beam power, whichever is selected, flows out of the dimmer switch, through the bulkhead connector, and to the lamp harness in the engine bay.

THERE IS NORMALLY ONLY ONE ground for both headlamps, somewhere on / near the radiator support. FIND AND CHECK that ground.

You should be able to probe the two bulkhead connector terminals for the high and low beams and by actuating the dimmer switch, get first one and then the other to power up.

Next move to the lamps. Find the ground, pull out at least on lamp. Bad ground, miss wiring, or even both lamps blown. That HAS happened!!

 

[67Dart273]

If you examine your (darn poor) circuit diagram, notice the top lamp in the drawing, wire L9-18BK. This means wire no. L9, it is no. 18 gauge, and BlacK. Notice the eyelet connector pictured next to the lamp. That is the ground.

L3-18R going to Y of the connector and
L4-18BK going to Z of the connector are the hi and the low power feeds to the lamps, coming from the dimmer switch.

If you get into the service manual, and look up the instrument panel wiring, find the high beam lamp, you will see that it is fed with wire L5, and if you follow that back to the bulkhead connector at Y , you will find L5 and L3 on the same terminal. This means that L3 is the HIGH beam power going to the lamps

The only one left is Z and L4 so that has to be lo beams power

 

[67Dart273]

Last, starting a new thread "cold" is not necessarily a good idea. We have no idea without digging around for the old thread(s) what you have done, whether it's been re-wired, or hacked, or what you have tried, checked and replaced.

 

[ricker4444]

The headlight circuit is dead nuts simple. The headlight switch has TWO power sources. The headlights ONLY are powered from a tap off the "welded splice" in the ammeter circuit, to a built in breaker in the switch. With the light switch full on, it feeds headlights power out of the switch, down to the dimmer. TWO of the terminals of the dimmer are ALWAYS hot with the switch ON. One terminal is power coming from the headlight switch, and the other is that power, selected by the hi/ low function of the dimmer, to feed out through the bulkhead and to the headlights.

The proper description for the dimmer is SPDT or Single Pole, Double Throw. This means it is switching ONE circuit (single pole) and selects which of two outputs which it feeds to (double throw)

IF THE power is getting that far, your cluster bright indicator should light when you actuate the dimmer.

The high and the low beam power, whichever is selected, flows out of the dimmer switch, through the bulkhead connector, and to the lamp harness in the engine bay.

THERE IS NORMALLY ONLY ONE ground for both headlamps, somewhere on / near the radiator support. FIND AND CHECK that ground.

You should be able to probe the two bulkhead connector terminals for the high and low beams and by actuating the dimmer switch, get first one and then the other to power up.

Next move to the lamps. Find the ground, pull out at least on lamp. Bad ground, miss wiring, or even both lamps blown. That HAS happened!!

I will check these and post once I am done. Thank you for the information!

 

[ricker4444]

The headlight circuit is dead nuts simple. The headlight switch has TWO power sources. The headlights ONLY are powered from a tap off the "welded splice" in the ammeter circuit, to a built in breaker in the switch. With the light switch full on, it feeds headlights power out of the switch, down to the dimmer. TWO of the terminals of the dimmer are ALWAYS hot with the switch ON. One terminal is power coming from the headlight switch, and the other is that power, selected by the hi/ low function of the dimmer, to feed out through the bulkhead and to the headlights.

The proper description for the dimmer is SPDT or Single Pole, Double Throw. This means it is switching ONE circuit (single pole) and selects which of two outputs which it feeds to (double throw)

IF THE power is getting that far, your cluster bright indicator should light when you actuate the dimmer.

The high and the low beam power, whichever is selected, flows out of the dimmer switch, through the bulkhead connector, and to the lamp harness in the engine bay.

THERE IS NORMALLY ONLY ONE ground for both headlamps, somewhere on / near the radiator support. FIND AND CHECK that ground.

You should be able to probe the two bulkhead connector terminals for the high and low beams and by actuating the dimmer switch, get first one and then the other to power up.

Next move to the lamps. Find the ground, pull out at least on lamp. Bad ground, miss wiring, or even both lamps blown. That HAS happened!!

So after testing what seems to be everything I am more frustrated than ever. I have power coming through the bulkhead on only one terminal which is Z. I show power at the ammeter goin in on the red terminal and power going out on the black terminal next to it. There is power on the headlight switch at B1 and B2 before I plug it in. I am not getting any power to the foot dimmer or coming out of X and Y which apparently feed the headlamps. I have zero instrument lights and no headlights.

 

[67Dart273]

If possible, and if you have not, you need to pull the switch out so you can access it. Maybe there is a really poor connection somewhere, just good enough to show power, but goes dead with a load

What all in the car works and what does not ? I assume this is a 67 Barracuda? You did not say or I missed it.

DOES THE hi beam indicator work? That branches off (red) at the interior side of the bulkhead connector

The dimmer is red, hi beams, bk, low, and light green, HL power coming from the light switch. B1 at the light switch is NOT fused (other than the main fuse link) and comes direct from the welded splice in the ammeter circuit

B2 feeds the park / tail circuit and also the inst lamps. That fuse also powers the 4 way flashers. That fuse on the diagram shows as 2nd from one end, next to the small INST fuse.

 

[ricker4444]

If possible, and if you have not, you need to pull the switch out so you can access it. Maybe there is a really poor connection somewhere, just good enough to show power, but goes dead with a load

What all in the car works and what does not ? I assume this is a 67 Barracuda? You did not say or I missed it.

DOES THE hi beam indicator work? That branches off (red) at the interior side of the bulkhead connector

The dimmer is red, hi beams, bk, low, and light green, HL power coming from the light switch. B1 at the light switch is NOT fused (other than the main fuse link) and comes direct from the welded splice in the ammeter circuit

B2 feeds the park / tail circuit and also the inst lamps. That fuse also powers the 4 way flashers. That fuse on the diagram shows as 2nd from one end, next to the small INST fuse.

 

[ricker4444]

I do have a 67 Barracuda Fastback. The hi beam indicator does not work nor does anything in the instrument panel. I do not have headlights. I do have parking lights, turn signals, 4-ways. I also have dome lights but they do not shut off when the door are closed.

 

[67Dart273]

Start by examining the service manual and notice which fuses do what and what works and not, etc. Part of your problem could be clear back at the fuse panel

IS THERE ANY chance that someone had a major problem and bypassed some stuff to get it to run? Maybe it's more basic, maybe in the ammeter /fuse link circuit.

 

[Mattax]

I tested to make sure I had power going into Z.

That's the battery feed/charge line.

It looks like Y is the hot feed to headlamp

It is the feed to the headlight high beam

It looks like Y is the hot feed to headlamp and X is like a return

NO. Its the feed to the low beam.
The headlights have a ground wire going to the radiator support. That's the return.

I have power on Z but no power coming out of Y. Does the power from the battery go directly to the bulkhead connector and then come out of Y to feed the headlamp or does it feed the switch first and then power the lamp?

The battery feed's the switch first, then the high/low switch, then to the headlights.

There also is a power feed from the alternator. This connects at welded splice in the harness.
Power will go to the switch from either the alternator or the battery. When the car is running, its the alternator because its power is at 14+ Volts rather than 12ish volts.

 

[ricker4444]

Start by examining the service manual and notice which fuses do what and what works and not, etc. Part of your problem could be clear back at the fuse panel

IS THERE ANY chance that someone had a major problem and bypassed some stuff to get it to run? Maybe it's more basic, maybe in the ammeter /fuse link circuit.

Start by examining the service manual and notice which fuses do what and what works and not, etc. Part of your problem could be clear back at the fuse panel

IS THERE ANY chance that someone had a major problem and bypassed some stuff to get it to run? Maybe it's more basic, maybe in the ammeter /fuse link circuit.

All the wiring is new to include the engine compartment and under dash

 

[Mattax]

I show power at the ammeter goin in on the red terminal and power going out on the black terminal next to it.

Black is a connection to the main splice where the battery feed joins the alternator and main feeds.
Both sides should always be hot.

There is power on the headlight switch at B1 and B2 before I plug it in. I am not getting any power to the foot dimmer or coming out of X and Y which apparently feed the headlamps. I have zero instrument lights and no headlights.

This is a clue that there is a poor connection.
Power is connecting, but when something is turned on the voltage drops to near nothing because the electrons can't flow through the resistance.
It's like having a clogged feed in a water line. When the faucet is off, there is full pressure there. But open the faucet wide and there's no pressure and only drop comes out.

I also have dome lights but they do not shut off when the door are closed.

One of the dome light wires is grounding.
The dome light is always hot. They turn on when any switch on the return wire connects with ground.

^ That's a schematic of how it works


Your 67 fastback's main circuits and connections look like this

 

[ricker4444]

All the wiring is new to include the engine compartment and under dash

The only thing on the switch that works is the the parking lamps

 

[67Dart273]

All the wiring is new to include the engine compartment and under dash

In that case you need to not only keep in mind "a problem, aka something broken," but the idea that there might be a wiring error in the new harness

As I said earlier you need to pull the switch out and probe the connections with the switch connected and turned on. This will load the system and if there's a poor connection, cause the voltage drop to show up

Part of this problem could be as simple as a poor connection at a fuse (not the headlamps)

 

[Mattax]

The ammeter will show if current is flowing.
Use that with your voltage readings to help figure out where the jam up is.
If the needle is centered, no current is flowing in or out of the battery.
Extreme positions are 40 amps discharge to 40 amps charge.
(Anything over 25 amps will cause damage if continues for long periods of time, and 40 amps will cause damage quickly.)

Everything below assumes engine off, so power is coming from the battery.
With the dome light on, the needle should show small discharge. maybe 5 amps.
The voltage at the battery positive and at main splice and the fuse box should be exactly the same. If not, there is high resistance in the line.
Because the alternator is not being used, you can take a voltage reading at the alternator's output stud to find the voltage at the main splice.

With the lights on the ammeter should show around 12 amps discharge. 9 amps to the headlights, and 3 to the parking and tail lights. If the dome light is on, then a little more.
The voltage at the battery positive and at main splice, the fuse box, and the headlight switch, should be close to the same. If not, there is resistance in the line.

The dome light, hazard, and parking/tail lights all share the same fuse.
At leasr on my 67, the wires are connected as shown above. The factory tried to avoid big splices and jointed wires together at terminals whenever possible.

 

[67Dart273]

The only thing on the switch that works is the the parking lamps

If that's the case, the lack of cluster lamps means that the problem is either a bad switch, bad cluster dimmer control, something wrong with the INST fuse circuit. All instrument wiring comes off that fuse FROM the dimmer and out on orange wiring

 

[Mattax]

Yup. Lack of power could be as simple as not getting one of the terminals clicked in well at the Z cavity.

 

[Mattax]

May be helpful

See Del's My review of Faxon book, 1967-1969 Dodge & Plymouth Body & Electrical Assembly Manual

hard top wiring diagram


Factory diagram pdferized with layers

Plymouth 67 Service manual Barracuda supplement available here

Service Manuals – MyMopar

mymopar.com

Parking and tail light power comes through the fuse to the B2 terminal on the headlight switch.
Inside the switch instrument lamps and radio lamp power splites off and runs through dimmer control and out to the 2 amp fuse.
Here's a schematic.

 

[ricker4444]

If that's the case, the lack of cluster lamps means that the problem is either a bad switch, bad cluster dimmer control, something wrong with the INST fuse circuit. All instrument wiring comes off that fuse FROM the dimmer and out on orange wiring

When you say “off that fuse from the dimmer” are you saying the dimmer on the headlight switch? I apologize for my lack of knowledge… I am trying to follow you guys the best I can

 

[Mattax]

See my edit to the post above.
'Dimmer'
He's talking about the control that allows us to adjust the brightness of instrument lamps.

 

[Mattax]

If you have working dome lights and parking lights, then the ammeter should be showing 5 to 8 amps discharging from the battery.
Is it ?

If so. Measure the voltage at battery and the voltage at the alternator's BAT terminal with the lights on.
Are they the same?

A more precise way to do it is measure the voltage difference directly.

If there is a voltage difference with 5-10 amps going through, then there is a bad connection between the main splice and the battery.


If there is voltage difference measured the first way, but not the second way, then suspect bad ground connections.


Final note, if the battery is getting run down, charge it on a charger.
Do not use the alternator to charge a battery when the battery is really low.
A low battery will draw a lot of current and as mentioned before, having 25 to 40 amps or more through the charge circuit for more than a brief period of time will damage stuff.

 

[ricker4444]

May be helpful
View attachment 1716333653
See Del's My review of Faxon book, 1967-1969 Dodge & Plymouth Body & Electrical Assembly Manual

hard top wiring diagram


Factory diagram pdferized with layers

Plymouth 67 Service manual Barracuda supplement available here

http://[URL]https://mymopar.com/service-manuals/

[/URL]

Parking and tail light power comes through the fuse to the B2 terminal on the headlight switch.
Inside the switch instrument lamps and radio lamp power splites off and runs through variable and out to the 2 amp fuse.
View attachment 1716333670

In order to trouble shoot the headlights and such do I need to hook up the printed circuit connector (round thing that goes on the pins)? I had pulled the wiring harness back out to go through it. The dash bezel and such are still installed

May be helpful
View attachment 1716333653
See Del's My review of Faxon book, 1967-1969 Dodge & Plymouth Body & Electrical Assembly Manual

hard top wiring diagram


Factory diagram pdferized with layers

Plymouth 67 Service manual Barracuda supplement available here

http://[URL]https://mymopar.com/service-manuals/

[/URL]

Parking and tail light power comes through the fuse to the B2 terminal on the headlight switch.
Inside the switch instrument lamps and radio lamp power splites off and runs through variable and out to the 2 amp fuse.
View attachment 1716333670

 

[Mattax]

No. None of the main feed wires go through the instruments.
The ammeter is mounted to the instrument panel but has its own connections. Electrically it is completely seperate from everything else on the panel.
Follow the wiring diagram like a map. Take your finger and follow the path needed for the electrons to move to the destination and return to ground.

The instrument cluster lamps are fed through the orange wire on the round connector and a wire on the straight connector. Those will be hot (or should be ) when the parking lights are turned on depending on the position of the dimmer. So don't let those ground or you may blow the 2 amp fuse.
The other stuff needs the key switch on as far as I remember.

The schematics that explain how a circuit works leave out some junctions etc. Their purpose is to show how it works so leaves out the details of how it all connects on the actual assembly.

However what is important is that no hot wires are hanging loose.
For example, if the door switch wires are not connected to the door switches, then they could be grounding. That would result in the dome lights being on.
But if a direct hot wire is touching ground, then there will be a short circuit.

edit---
Main feed wires:
Battery to main splice (A, and R6A)
Alternator to main splice (R6)
Power to Headlight Switch B1 terminal, wire L1 Black with stripe
Power direct to Fuse Box, Q2 Red with Stripe
Power to Key Switch, J1 Red


Coming off the fuse box, the pink wires and the red to cigar lighter are always hot if the fuses are installed.