headlights not working

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Cuda Hunter

Cuda Hunter

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I don't post here often although I scroll through threads daily.
Maybe yal can help me out a little.

67 barracuda.

I had a halo kit put into the car. Worked fine for maybe 100 miles.
Now the lights won't come on. Halo's work fine, parking lights work fine tail lights work fine blinkers work fine.
No fuses are blown. No parasitic draw on battery when the car is off.
checked several grounds and they appear fine, loosened and re tightened.

Battery shows 12.59 not running.
When this happened my battery died and I lost all lights on the ride home. Jumped it and it drove home.
car in off position I get 10.5 amps at rear of altenator. car running I get 20 at rear of altenator.

I unplugged the 3 prong for the headlight and I get nothing from that.
Would this be a headlight switch problem? Even though parking lights and halo's work? Brights switch on floor?
How would I test the headlight switch and what amperage from where should I be getting?
 
I'll snap a few pics of the system. Pretty basic. Plug in system. Has one relay that appears to be for the halo part of the system. Give me a few.
 
Not sure of the brand. As it appears it is only wired into the one set of wires in the picture.
The red/black and green/white combo's come from the relay and control the halo.
The main headlight section is the same lines that would go to a regular headlight 3 prong.

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First thing I'd check is the dimmer switch

The HL switch has two sources of power. One powers tail/ park and dash lights, the other powers ONLY the headlights. That is UNFUSED power from the splice in the black ammeter wire

From the HD switch it goes to the dimmer, than out through the bulkhead on the high and low beam wires and around to the headlights.
 
67Dart273 said:
First thing I'd check is the dimmer switch

The HL switch has two sources of power. One powers tail/ park and dash lights, the other powers ONLY the headlights. That is UNFUSED power from the splice in the black ammeter wire

From the HD switch it goes to the dimmer, than out through the bulkhead on the high and low beam wires and around to the headlights.
Click to expand...

"20v at the back of the alternator"?
 
Cuda Hunter said:
yeah that's what I thought I read. Was surprised. That's at the main stud on the alt.
I figured it was supposed to be at 13 or so from the battery right?
Click to expand...

13.5-14.5 or so I believe.
The voltage regulator keeps the input voltage down to whatever the charging voltage should be, so the output stud shouldn't be more than about 14.5 max.
 
I"m getting 20 at the larger stud on the alternator. would that mean I have yet another bad voltage regulator? That wouldn't be the reason my headlights aren't working would it though?
 
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So on the headlight switch.
engine off, lights off.
Black wire shows 12.20 and two pinks show 12.20
engine off lights turned on I get 11.2 on the double pinks,12 on the black,10 on the brown
engine on lights on I get 12 on the black, 10.5 on the pinks, 10.5 on the brown and 10.5 on the yellow and black combo.

All this with nothing coming through the dimmer switch. I am not getting any readings off the dimmer switch.

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Cuda Hunter said:
I"m getting 20 at the larger stud on the alternator. would that mean I have yet another bad voltage regulator? That wouldn't be the reason my headlights aren't working would it though?
Click to expand...
TWENTY??? You might have a failed master splice, the one I just mentioned. Here is what you do.......

Disconnect battery ground, and disconnect alternator Take an ohmeter and connect one end to the alternator terminal, and the other to the "big stud" on the starter relay. Should be zero ohms. Wiggle the bulkhead connector. If you don't get "anything" it might be in the bulkhead connector, it might be in the master splice that I mentioned above. You MAY have blown up something, headlights? Relays?

Don't you have a service manual? Go download one, for free, at MyMopar You may have to settle for Dodge vs Plymouth, or vice versa

Checking power out of the light switch may not tell you much as you MUST LOAD it as the meter is not a load. You need something like an old stop / tail lamp socket and bulb so you can put a load on the lights circuit under test
 
Ok, so with the ohm meter hooked up do I turn the vehicle to the on position? Or just turn on the headlight switch? What is supplying power while I'm looking for the resistance?
I'm assuming there should be a resistance measurement when this is hooked up like this when I wiggle the bulkhead connection.
Just a little confused, if there is supposed to be zero resistance just sitting like this what does wiggling the bulkhead actually do to supply a measurement?
I'm not electrically inclined as you can tell.
 
Unhook the battery, and no do NOT turn anything on. What we are trying to see, here, is if the "path" from the alternator to the battery is OK, and "I'd guess" it is not. Wiggling the bulkhead connector may give you a clue if the trouble is in there.

So with the alternator black wire (nut and stud) disconnected, connect your ohmeter to that black wire/ eyelet. Then connect the other meter lead to the big stud in the starter relay, or to the battery positive post. AGAIN the battery ground MUST be disconnected.

You are hoping for a very low ohm reading, the lower the better.

Another thing you could do is run the engine at fast idle with everything wired up "normal" and clip your meter to the alternator stud and ground. Wiggle the bulkhead connector and see if you can hear arcing, smell or see smoke, or see the meter reading fluctuate.
 
Ok, so I couldn't get the ohm reader to work so I hooked up my vantage multimeter .
First I couldn't get anything to work using the starter as it's really tight in there. So I hooked it up to the negative on the battery cable and the black wire for the alternator.
Zero resistance, but when I wiggled the bulk head I got between 2. and 11. I'm assuming amps.
So I took the center section of the bulkhead apart first and found this black wire was fried and separated. I'm again assuming, this is a ground since it's a larger gauge black wire.
It appears that the wire into the bulkhead connector is not fried and long enough to connect these two together again.
Is this what I should be doing? connecting these together again. Or would you think there is further damage? the bulkhead connector does not appear to be burnt or melted.

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No you should not be measuring amps. Shoot a good clean photo of your meter, or at least post the model number of your multimeter

Whatever that mess is in the last photo is for sure hacked up and needs attention.
 
Cuda Hunter said:
I'm assuming amps.
So I took the center section of the bulkhead apart first and found this black wire was fried and separated. I'm again assuming, this is a ground since it's a larger gauge black wire.
Click to expand...

What do you mean "assuming amps?" To read amps you need either a DC clamp for your meter or read the circuit in series. The only grounds in the engine bay are small gauge for lights, and straps for the negative cable. Color does not indicate use always, there's main alternator wires that are med gauge - #14 to #10 that are main current carriers.

Replace that entire mess, the copper will oxidize black at those crimp splices.
 
Well, I inherited that mess. In order to replace that mess I need an entire wiring harness. That is in the plans but at this moment I don't need the car to be undrivable. So I would like to fix the problem at hand.

Would the voltage regulator going bad and allowing 20 amps through the system cause this wire to burn up?
 
the smaller one I can't seem to get a reading out of on any of the ohm settings.
I don't see in the menu on the vantage where to set it to read ohms. So i just put it on multimeter and checked it that way and got zero's until I wiggled the bulk head.
I did say I'm not electrically inclined right. Not afraid, but not exactly sure.

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I cannot tell for sure "I guess" you have the probes correct in the bottom photo. You need to turn the selector switch to "ohms" to the lower right where it says "200" right next to the "diode" symbol

What model is the top one, I cannot tell


Demonic, above, mentioned color of wires. THIS IS IMPORTANT. The alternator output wire is a large BLACK. It most certainly is NOT ground, and IS NOT fuse protected. This same wire goes in through the bulkhead and connects to the ammeter.
 
I had it turned to the 200. Tried it at the 2K also but neither worked. Maybe it's the machine.
The other is a vantage MT2400.
 
The black wire that was burnt up is the same gauge wire as the black wire on the alternator.
Goes through the wire loom and is wrapped up so I have not traced it to see if it's the same one.
 
You can fix all that "mess" much more correctly by cuttin out those butt connectors. "I" would just slide some shrink sleeve over each one and solder the wires together and shrink the sleeves over each one. That's way more acceptable and wouldn't take too long. You obviously must do it to one.
 
Cuda Hunter said:
The black wire that was burnt up is the same gauge wire as the black wire on the alternator.
Click to expand...
That's the alternator output wire. R6 in the diagram.
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It provides all of the power to the car when the alternator is turning fast enough.
basic-charge-circuit-charging-animated-gif.gif

It, and all of the wires connected to the main splice are connected to battery positive. Which means if any of them touch ground the battery will discharge.
If you want to measure continuity with an ohm meter, disconnect the battery.

Volts. Volts are like pressure in a piped water or air system.
A fully charged battery will have just over 12.5 Volts.
The alternator is regulated to have an output 'pressure' around 14 Volts.
Amperes. Amps are flow like gallons per minute in a piped system. The dash gage shows amps in or out of the battery. 40 to 40.

When the headlights are turned on with the engine off, current flows from the battery to the headlight switch. The dash gage should show approximately 10 amps discharge. The battery voltage will drop a little but should still be around 12. Voltage will drop as the current flows through resistance in the circuit.
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At the main splice the current stream splits, some flows to the headlight circuit, some to the parking lights. If you had the door open, some also goes to the dome or courtesy lights. Voltage at the ignition switch, alternator output stud should be the same as at the main splice unless the connection is broken.

While cleaning this mess up, I'd take that halo thing and kick it down the road. The last thing these cars need is additional electric loads, especially on on the headlight circuit. These things were built for 40 W/40 Watt headlamps. For that, the wiring was adaquate - when in good shape.
 
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Cuda Hunter said:
I had it turned to the 200. Tried it at the 2K also but neither worked. Maybe it's the machine.
The other is a vantage MT2400.
Click to expand...

I tried looking up a user manual for the MT2400 with no avail That is a graphing meter. Far more than a simple multimeter
 
I have similar lights in my 67 B'cuda. They are wired though relays to take the load off headlight switch and factory wiring. You might pull those lights and find the wiring crushed against the back of the headlight house. I had to replace the OEM connectors with a offset lower profile connectors.
New Dorman Lamp Socket Light, 84790 for sale online | eBay
 
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