Had headlights, then high beam only, now nothing

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Bill440cars

Old Mopar Man That Likes Old & New Skool
Joined
Apr 14, 2019
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Location
Perryville, Arkansas
So, I knew I had seen a dimmer switch around here, in the stuff, my Dad had. So, I found it, checked it with my ohm meter, seemed good. Put it in and thought my problem was solved, but it wasn't. So, I am still trying to figure out what happened?
Help!
 
Don't trust hi current stuff with an ohmeter. Under load, the contacts can fail

Just trace it out, you have a diagram?

Functional path is from HL switch to dimmer, out the dimmer on low and high beam wires, through the bulkhead, and to the headlights, which are grounded through a common ground. So check that

Backtrack with your meter/ test lamp. Figure out where the HL are in the bulkhead connector, see if you have power there, backtrack to the dimmer
 
Don't trust hi current stuff with an ohmeter. Under load, the contacts can fail

Just trace it out, you have a diagram?

Functional path is from HL switch to dimmer, out the dimmer on low and high beam wires, through the bulkhead, and to the headlights, which are grounded through a common ground. So check that

Backtrack with your meter/ test lamp. Figure out where the HL are in the bulkhead connector, see if you have power there, backtrack to the dimmer

I have a wiring diagram, but it's hard to tell much, as it could stand to be enlarged some, so I can better tell what is what, on this one. But, it is the best I have, would you, by chance, have a more simplified diagram ? Also, I need to know where the headlight relay is, on this one? Gotta go set up my light, it is way past dark thirty here in Arkansas. I appreciate the info that you have offered. I figured, as late as it is, nobody would be on here. All input greatly appreciated
 
Green is feed into dimmer. violet is low, red is high for outputs.
 
check the grounds, must have a good grounding circuit
 
they were working, then they weren't, then only high beam, now nothing. Got dash lights. I'll check the rest, to be sure. I think it is only the headlights, that are effected
Dont rule out bad bulbs till you have tested them. Long shot but maybe you are running to high a voltage an burnt out the low beam then switched to high beam and burnt them out as well.
Mymopar.com has free pdf of wiring diagram that you can enlarge
 
Dont rule out bad bulbs till you have tested them. Long shot but maybe you are running to high a voltage an burnt out the low beam then switched to high beam and burnt them out as well.
Mymopar.com has free pdf of wiring diagram that you can enlarge

I appreciate that. Here's what happened today. I had ordered a headlight switch through O'Reilly's (same Standard P/N and it was supposed to be in today. It wasn't. I had been told that there were 2 of the headlight switches at a Main O'Reilly's in North Little Rock (I'm in Arkansas, in case that was missed). North Little Rock is at least an hour to an hour & a half. So, I decided to make the trip, since it was during the day & go get a switch myself. So, I did that. On my way home, I had to stop by and pick up my Wife from work anyway. Before we got home, I had to also pick up my Daughter, from a friend's home. And, on the way there, there was a series of speed bumps and one snuck up on me. and it jarred the front of the car pretty good. Anyway, we got home & I went to replace the switch & did so. so I had high beam, but no low beam. I started the motor and on high beam, no problem, but on Low beam, there was a heavy discharge & the motor was running a little rough, on low beam. So then, I thought that maybe I had knocked one or both of the low beam elements loose. So, I pulled both headlight bulbs (sealed beams) and checked each one, individually and they checked out great. Also, I have 2 dimmer switches (the original & a spare used one. I get the same issue with both. One thing I did notice and didn't really think anything about it. The new switch has a terminal on the metal cover plate, where the original one didn't. I am sure it would be a ground. Could THAT be causing my problems that I am having now? Also, isn't there a headlight relay, on here somewhere? I will check out that wiring diagram too, Thank you for that. I do need to enlarge it some, the others, are like "Fine Print" to me. Appreciate all the input I can get too, Thank you folks
 
Print out a hand full of the wiring diag. And get some fine line hiliters in varous colors.

Start at a bulb and highlight the wire trace along the entire run. Do the same for another cir like flashrrs on another copy, etc.

Dont try to do multiple cirs on one copy, too confusing

(BTW...My wifes family is from McCrory)
 
Print out a hand full of the wiring diag. And get some fine line hiliters in varous colors.

Start at a bulb and highlight the wire trace along the entire run. Do the same for another cir like flashrrs on another copy, etc.

Dont try to do multiple cirs on one copy, too confusing

(BTW...My wifes family is from McCrory)
Thank you, for the input. I have been taking care of my own vehicles, for a long time and I have never had issues, like this or similar issues like I had with our '08 Town & Country, with their complicated electrical system. Maybe I am just getting too old, to cope, like I have for so long. (I'm 72 & tired.)
 
The new switch has a terminal on the metal cover plate, where the original one didn't. I am sure it would be a ground. Could THAT be causing my problems that I am having now?
I just changed my headlight switch in a 1974 BC my dimmer didnt work. I also had a spare spade terminal on the new switch. Still worked fine. I imagine it's made that way for multiple year fitment. I'm betting bad ground on the radiator support/ firewall on the harness. Or dimmer switch. Both easy to change/check. I rock auto cheapo stuff like this to just have around as spares... literally got a high beam switch for $2. Headlight switch for maybe $5
 
I just changed my headlight switch in a 1974 BC my dimmer didnt work. I also had a spare spade terminal on the new switch. Still worked fine. I imagine it's made that way for multiple year fitment. I'm betting bad ground on the radiator support/ firewall on the harness. Or dimmer switch. Both easy to change/check. I rock auto cheapo stuff like this to just have around as spares... literally got a high beam switch for $2. Headlight switch for maybe $5

Thank you, for the input on the spare terminal. I figured it had to be a ground, with it on the cover plate, which made me wonder if I needed to make a lead and attach it. I agree, with Rock Auto and use them quite a bit, for a lot of things.

Just to be clear, as to what started all of this, what I've done & what the end result was last night, so we all are on the same page, so to speak:

Driving home from town, a few nights ago, suddenly the low beams went out. I quickly went to high beam. just as I got home, the high beam went out too.

Well, I hit the dimmer switch a few times - Nothing!
Turned the headlight switch off & on a few times - Again, Nothing!

I knew I had another dimmer (used) switch. I checked it, with my meter & it
seemed to function like it should. So, I put that one on, tried it & Again, Nothing!

So, from all I had read, on here & when I googled the problem, the majority of
issues pointed to the Headlight Switch.

I looked around, on the forum, as well. And the next thing I knew, it was 1;00AM
and I started on this, around 8 or 9:00. So, I quit and went to bed.

The next day, I started getting into it deeper. Also, I ordered a headlight switch,
because it wasn't expensive & having a spare would be good. From this point on,
I have checked the headlight bulbs - both work, on high & low beams.
I checked the ground wires that are located by the battery & next to the radiator
& cleaned the them.

A question I have asked and I don't remember getting an answer to, "Is there a
headlight relay? If so, where is it & could That be a problem?

Now, yesterday afternoon, after I actually had to go get the headlight switch
from an O'Reilly warehouse (a little over an hour away), I started working on
replacing that headlight switch. So, I get the switch hooked up & in place. I try it
out. I had high beam, but still no low beam. And when I tried the low beam, there was a heavy discharge on the battery. So, I start it up & on "low beam,
there still was a discharge and the motor was missing! I have absolutely NO idea what happened, to give me THAT problem! Now, yesterday afternoon, before I got home, I had to run an errand, where I came across a series of "speedbumps"
& 1 of them snuck up on me. when I went over it, it was pretty hard on the suspension, which makes me wonder if I somehow damaged something, electrical
yet the charging system only acts up, when on low beam! I am totally confused, as to how or why all of this is going on & I don't know IF the speed bump issue has anything to do with it or not. I just need help, if anyone has had anything similar or feels they can shed some light on this. Sorry about the lengthy post. I am just totally frustrated, at this point. input definitely appreciated.
 
Thank you, for the input on the spare terminal. I figured it had to be a ground, with it on the cover plate, which made me wonder if I needed to make a lead and attach it. I agree, with Rock Auto and use them quite a bit, for a lot of things.

Just to be clear, as to what started all of this, what I've done & what the end result was last night, so we all are on the same page, so to speak:

Driving home from town, a few nights ago, suddenly the low beams went out. I quickly went to high beam. just as I got home, the high beam went out too.

Well, I hit the dimmer switch a few times - Nothing!
Turned the headlight switch off & on a few times - Again, Nothing!

I knew I had another dimmer (used) switch. I checked it, with my meter & it
seemed to function like it should. So, I put that one on, tried it & Again, Nothing!

So, from all I had read, on here & when I googled the problem, the majority of
issues pointed to the Headlight Switch.

I looked around, on the forum, as well. And the next thing I knew, it was 1;00AM
and I started on this, around 8 or 9:00. So, I quit and went to bed.

The next day, I started getting into it deeper. Also, I ordered a headlight switch,
because it wasn't expensive & having a spare would be good. From this point on,
I have checked the headlight bulbs - both work, on high & low beams.
I checked the ground wires that are located by the battery & next to the radiator
& cleaned the them.

A question I have asked and I don't remember getting an answer to, "Is there a
headlight relay? If so, where is it & could That be a problem?

Now, yesterday afternoon, after I actually had to go get the headlight switch
from an O'Reilly warehouse (a little over an hour away), I started working on
replacing that headlight switch. So, I get the switch hooked up & in place. I try it
out. I had high beam, but still no low beam. And when I tried the low beam, there was a heavy discharge on the battery. So, I start it up & on "low beam,
there still was a discharge and the motor was missing! I have absolutely NO idea what happened, to give me THAT problem! Now, yesterday afternoon, before I got home, I had to run an errand, where I came across a series of "speedbumps"
& 1 of them snuck up on me. when I went over it, it was pretty hard on the suspension, which makes me wonder if I somehow damaged something, electrical
yet the charging system only acts up, when on low beam! I am totally confused, as to how or why all of this is going on & I don't know IF the speed bump issue has anything to do with it or not. I just need help, if anyone has had anything similar or feels they can shed some light on this. Sorry about the lengthy post. I am just totally frustrated, at this point. input definitely appreciated.
 
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The headlights, and the headlights only - not the parking lights, are protected by a circuit breaker inside the headlight switch.
Did you check the bulbs?

Dont rule out bad bulbs till you have tested them. Long shot but maybe you are running to high a voltage an burnt out the low beam then switched to high beam and burnt them out as well.
^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^
Start at the headlights and work back.
Take the lamps out, and do a check to see if the bulbs are burned out. Ohmmeter, test lamp, hook them to a battery...whatever method works for you.
If they are burned out, then Dana has mentioned one likely cause. If not continue on the main investigation.
Then look over the connectors and follow the wires to the ground looking for damage in connections or insulation, as well as signs of heat.
Check the insulation on the feeds carefully. If it chafed through on the headlight buckets, that would be a reasonable cause for the breaker to open. I've had it happen.
Then onto the bulkhead connector - the shop manual for your year will have which cavity has the high and low beam wires. On the inside do the same back to the hi/lo switch.
 
The headlights, and the headlights only - not the parking lights, are protected by a circuit breaker inside the headlight switch.



^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^
Start at the headlights and work back.
Take the lamps out, and do a check to see if the bulbs are burned out. Ohmmeter, test lamp, hook them to a battery...whatever method works for you.
If they are burned out, then Dana has mentioned one likely cause. If not continue on the main investigation.
Then look over the connectors and follow the wires to the ground looking for damage in connections or insulation, as well as signs of heat.
Check the insulation on the feeds carefully. If it chafed through on the headlight buckets, that would be a reasonable cause for the breaker to open. I've had it happen.
Then onto the bulkhead connector - the shop manual for your year will have which cavity has the high and low beam wires. On the inside do the same back to the hi/lo switch.

There s a white wire on the left headlight connector, that is hot & the switch itself is very warm, to the point of being somewhat hot.
 
Also, where is the headlight relay & what does it look like?
{Reminders, if it will help: With the old headlight switch, no headlights
With the new switch, got high beam
Try low beam, & it's like a dead short & pulls car's amp
meter, strongly, to discharge!
and the back end of the light switch gets very warm &
close to being hot.

Still checking things out, by the way. just need whatever info or thoughts, you all might have, that could help me get this done. Much appreciated.
 
There is no relay OEM. The functional path is.........tapped off the black ammeter wire "welded splice"............to the headlight switch....through the switch .........to the dimmer switch........out the dimmer on high and low beam wires...........through the bulkhead connector.............to the headlight harness..........split off to the two lamp connectors.........to ground somwhere on the radiator support
 
The headlights, and the headlights only - not the parking lights, are protected by a circuit breaker inside the headlight switch.



^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^
Start at the headlights and work back.
Take the lamps out, and do a check to see if the bulbs are burned out. Ohmmeter, test lamp, hook them to a battery...whatever method works for you.
If they are burned out, then Dana has mentioned one likely cause. If not continue on the main investigation.
Then look over the connectors and follow the wires to the ground looking for damage in connections or insulation, as well as signs of heat.
Check the insulation on the feeds carefully. If it chafed through on the headlight buckets, that would be a reasonable cause for the breaker to open. I've had it happen.
Then onto the bulkhead connector - the shop manual for your year will have which cavity has the high and low beam wires. On the inside do the same back to the hi/lo switch.

good info above. there are some questionable OEM crimp type splices near your battery tray area, on both sides of the radiator support.

Also, do your turn signals work as they should? If you have a bad ground on the radiator support...the power from the turn signals will illuminate the turn bulb (Key on), but it can't "ground" to activate the flasher. saw that happen once.

again physically test the bulbs too... pretty easy to pull out and test HI and LOW right on the battery with a jumper wire.
 
There is no relay OEM. The functional path is.........tapped off the black ammeter wire "welded splice"............to the headlight switch....through the switch .........to the dimmer switch........out the dimmer on high and low beam wires...........through the bulkhead connector.............to the headlight harness..........split off to the two lamp connectors.........to ground somwhere on the radiator support

I wasn't sure about the relay, the wiring diagram shows one and that is what I was going by. Thanks for clearing that up. Had to back off, for awhile, I wasn't getting anywhere & tomorrow, Wife has to go to work & my oldest Daughter, has a medical procedure & here we are, stuck & fortunately my Wife was able to go with our neighbor, to get a "rental", to take up the slack, until I can get this one back up &/or
we finally get our Town & Country fixed & back to us. Yeah, I know he term "When It Rains, It Pours, Very Well. Again, every bit of help I receive here, is VERY much Appreciated. And, Anytime I can, I'll definitely return the Favor. This has just really thrown me sideways, after dealing with some electrical issues on our Town & Country, as well. And I DON'T like the electrics on the newer Mopars, AT ALL.
 
Still checking things out, by the way.
It has to be methodical. The fact you are struggling with what the meters can tell you is OK. But jumping around is throwing darts blindfolded.
Start at one end, where the trouble was spotted (the headlamps) and work back. Do it in pictures. or do it in writing. Its very hard to help when we have to read between the lines.
Try low beam, & it's like a dead short & pulls car's amp
meter, strongly, to discharge
!
Is it over 20 amps? (meter is 40 amps to 40 amps, center is zero)
If over 30: DANGER DANGER Will Rogers! STOP.
Reading between the lines here, I'm going to make the following assumptions:
Engine is off, key is off, headlights are working.
If so, then yes it is likely a short in the headlight circuit. There's enough resistance it didn't pop the circuit breaker right away. The breaker on stock headlight switch is 15 amps. But if you used a switch for another model, then it could have a 20 amp breaker.
There is no relay OEM. The functional path is.........tapped off the black ammeter wire "welded splice"............to the headlight switch....through the switch .........to the dimmer switch........out the dimmer on high and low beam wires...........through the bulkhead connector.............to the headlight harness..........split off to the two lamp connectors.........to ground somwhere on the radiator support
^^^^^^^This^^^^^^^^^^^^^^^^

Don't know what year your car is, but if you prefer drawings, schematically its like this.*
Colors and details below are 68 or 69. Check the FSM for specifics for your year and model.
upload_2019-5-20_14-11-2.png


*1976 the concept is similar but the scheme is more involved.
 
Sorry, I guess I was so thrown, by the sudden problems (after having dealt with some problems we had, with a 2008 Town & Country, I got flustered and didn't make very good posts, to include not specifying the vehicle details. my car, is a 1971 Dart Swinger. another bit of info, is that this car was built originally as a 198 Slant 6 Automatic model and Some Where, along the way, someone swapped the Slant 6, for a 318. So, the wiring for the 318, was brought with it & the electronic ignition box & the electronic voltage regulator, along with their wiring, was blended in, with the original pieces. The engine compartment isn't as neatly laid out, as it was, from the factory.

Now, to the problem. Both headlights were on low beam and suddenly they went out. I tried to get them back, by cycling the dimmer switch a few times, but didn't work, so I left it on High Beam & made it on home. Just as I pulled in the driveway, the high beams went out. I cycled the dimmer switch, yet again (not knowing the condition or age of that switch. Again, it didn't work. So, my first thought was that the dimmer switch (being who knows how old) might b the issue and since I had one on hand, I tried it. Didn't help anything. It did occur to me, to check the headlight bulbs & I did just that, checked both beams of both head lights, because I didn't want to be tearing into this, when all along it could be the bulbs, though each beam of both sides, went at the same time.

I have taken the ground loose, by the radiator, cleaned up the area & the terminals & reinstalled them. I have also removed the 3 bulk connectors on the firewall (1 at a time, I looked them over, cleaned & reinstalled them).

Now, I don't have the sealed beams installed, right now. But I turned the headlight switch on & the violet wire gets hot, BUT, there is no voltage there. And that is as far as I have gotten, so far. had to stop & work on getting a rental vehicle & a way to get there. Oops, forgot to include that with the new headlight switch, the high beams work with or without the engine running. Low beams, cause the amp meter to jump quickly, to the left (discharging, of course).
 
Now, I don't have the sealed beams installed, right now. But I turned the headlight switch on & the violet wire gets hot, BUT, there is no voltage there. And that is as far as I have gotten, so far. had to stop & work on getting a rental vehicle & a way to get there. Oops, forgot to include that with the new headlight switch, the high beams work with or without the engine running. Low beams, cause the amp meter to jump quickly, to the left (discharging, of course).
Oops, forgot to include that with the new headlight switch, the high beams work with or without the engine running.
Please take the time to look at what 67Dart273 wrote, or the schematic I posted, or both.
Follow the flow path from each power source to the headlight switch. When the alternator is working, power flows from it. When the alternator is not providing power, it flows from the battery. In both cases it goes through the main splice. High beam, low beam, it doesnt matter.

Low beams, cause the amp meter to jump quickly, to the left (discharging, of course)
Any time the ammeter swings all the way to either side is really bad. That's 40 amps or more! You will damage the system running that much current through the circuits. Stuff will melt, and if there are combustibles near the hot wiring there will be a fire.

Now, I don't have the sealed beams installed, right now. But I turned the headlight switch on & the violet wire gets hot, BUT, there is no voltage there.
Can't comment on voltage, but there is current flowing through there. Its getting back to ground even though there's no lamps in the sockets.
The fact its getting warm means that the voltage is higher on one side of that hot area than the other. How much higher and how much above ground really doesn't matter.
 
OP......check your battery voltage when running at "high fast idle." You may have a problem causing bad over voltage. Is the battery bubbled over?
 
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