headlight problem.. help!??

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barbee6043

barbee6043

barbee 6043
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traded my NO problem mopar for this 72 duster /6 car. took to get inspection, passed, had headlites dim and brights. dimmer switch stuck, soaked with penetrant, but spring is weak.
head to work in dark, got dims, mash dimmer, for bights... no nothin!! put back on dims, got lights .... to work (32 mi) through the sticks.
replace dimmer switch with new one, next mornin, got dims, mash dimmer, no brights, put back on dim, head out, then... NO lights except parkin lights!
just took out headlight switch, looks like new! guess the other guy had problems but forgot to mention it durin trade!?? in MO we call that a horse trade S------!
can anyone tell me which terminal in headlight switch will go to headlights??? or what else to check for?? is there a fusible link for headlights?? any help greatly appreciated.
 
How (what condition) does the switch and harness connector look?

The main headlight ONLY (not tail, park or dash) is supplied to the switch by a wire coming from what is commonly known as the "in harness splice" which is a Great Big splice in the black ammeter wire. This is NOT fused before the switch, and the headlight switch has a built - in breaker.

From the switch, power goes to the dimmer which selects high, low, then out through the bulkhead connector.

The bulkhead connector, dimmer switch and it's connector, headlight switch and it's connector are probably your biggest suspects.
 
the headlight switch is new for sure. i just relaced the dimmer switch. i find no current at dimmer. layin on my back lookin unside down into guts of dash is hard on old guys like me. ( come to think of it, was hard back in "85 when i drug home my first mopar!
sounds like i should have power at dimmer if headklight switch is good???? got a new on to be at parts store in a m but don't want to buy it if thats not the problem. i remember havin problems with wires at firewall connection, usually the main red ho wire goin in. thanks for you help.
 
You REALLY need to do something about your computer. I don't know what classifieds, Craigslist, etc, in your area, but around here 100-150 would get you a useable laptop to get on the www and be able to download stuff

What is the model, etc, of your computer that you don't think works?
 
installed new headlight switch and all works. like you said, still lookin for a short. the new switch has lifetime warrenty, but will be of no help headed to work at 5 a m thru 32 miles of dark, but now sunrise is at about 5 45!! LOL some where on here a guy was telling how to test at lights for a short? maybe i got DRS disease?? don't remember swatttt??!!
 
Pm Rob aka 'crackedback' he makes a relay based headlight wiring add on that is amazingly easy to install and dirt cheap. there is a thread for it in the exterior parts for sale forum
 
Best thing is replace that insufficient factory wiring with a relay set up.
 
It sure sounds like you replaced your bad floor switch with a new bad one. It's just a simple Single Pole Double Throw (SPDT) switch. Power comes into the common terminal from the headlight switch then goes out to either the high or low terminal. You should get output voltage at both (not at the same time) as you cycle the switch.
 
You can bypass the floor switch with a spade-spade jumper. You will have low-beam only, but that will get you to work and back for now. Pull the wires out from under the carpet since they might be frayed and shorting down there.

And thanks to 67Dart273 for translating your questions. I couldn't make sense of what you thumbed into the phone.
 
I've seen a couple of cases where the bulbs were the problem. Right high beam had died and owner didn't notice until left high beam died.
 
all headlights would go out. replaced switch and so far all o k. I realize the relay system is probably great but have other things I need worse. I have a feather duster that's on the road now so other car is spare.
 
The relay setup does not repair the cars original wiring. It only changes the high current source. In other words, If the headlight switch doesn't signal the relay it wont function either. Sometimes the problem isn't in the switch itself but the harness connector attached to it. Look closely inside and outside of that connector. There may be a female terminal in it that is nearly disintegrated. Once a fault like that is corrected the relay setup can prevent its happening again.
 
i did find some plastic that had deteriorated around one of the female connectors in the connector at the switch. course now i got a leaking front seal on trans on the other duster i'm drivin to work! LOL. maybe a relay system will be in the financial cards somewhere in the future!?? or probably get down to just one duster!?? i know fool well i can't afford relay system for both!!!!!
 
Things that have not been mentioned are the headlight ground connections at front, and crusty fuse terminals in fuse box. These would both be poor connections. Shorts blow fuse, or trigger thermal protector in headlight switch.

Forget the Fuses! The switch circuit breaker provides the protection.
 
I agree with Kit. I don't think relays are essential with stock headlamps. Indeed, we may see LED headlamps in the near future with much less current draw. That said, I put my Dart & Valiant headlamps on relays, but only because I installed a modern relay box and had plenty.
 
KitCarlson said:
crusty fuse terminals in fuse box. . Shorts blow fuse, or trigger thermal protector in headlight switch.
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So do "crusty connections." Bad connections, IE rusty, loose/ corroded fuse spring clips make HEAT, and that effectively lowers the amp rating on the fuse. Same thing with any breaker. You mount a breaker in your engine bay, say, for a trailer brake, and the engine heat causes it to trip early.

In the headlight switch, poor connections in the switch connector, the switch contacts, or the breaker contacts themselves makes heat --which heats up the breaker -- and causes it to trip early.

("Kit" (Dave) may've been tryin' to say that but I didn't get it from his post)
 
BillGrissom said:
I agree with Kit. I don't think relays are essential with stock headlamps. Indeed, we may see LED headlamps in the near future with much less current draw. That said, I put my Dart & Valiant headlamps on relays, but only because I installed a modern relay box and had plenty.
Click to expand...

Most people say that until they see the difference!

There is a HUGE improvement in lighting efficiency with a relay kit using proper gauge wire. Ask the people that run them. Not to mention the other benefit of taking that load off the bulkhead and switch.

The stock wiring causes a lot of voltage drop when in perfect working order.
 
Don't know if this is much help, but...I had a 72 Fury and the headlights would just go out, I would just keep stepping on the dimmer switch and eventually they would come back on, replaced the dimmer switch, thought that fixed it until it did it again, then replaced the headlight switch and it never happened again. I used to carry a spotlight(used a sealed beam like a small headlight)that plugged into the cigarette lighter when the lights went out I would hold the spotlight out the window and continue down the highway.
 
67Dart273 said:
So do "crusty connections." Bad connections, IE rusty, loose/ corroded fuse spring clips make HEAT, and that effectively lowers the amp rating on the fuse. Same thing with any breaker. You mount a breaker in your engine bay, say, for a trailer brake, and the engine heat causes it to trip early.

In the headlight switch, poor connections in the switch connector, the switch contacts, or the breaker contacts themselves makes heat --which heats up the breaker -- and causes it to trip early.

("Kit" (Dave) may've been tryin' to say that but I didn't get it from his post)
Click to expand...
I think you are confusing resistance & current. The amp rating of a fuse or circuit breaker remains constant regardless of resistance in other parts of the circuit. The heat will be at the point of highest resistance. A fuse is just a part of the circuit with designed in resistance that will pop when overheated for overload protection. In theory the fuse should be the highest point of resistance. When current rises over the rated amount the fuse heats up & blows.
If you're pulling a trailer that causes enough engine heat to trip circuit breakers & blow fuses then you have a lot more to worry about! The breaker or fuse probably blows from the added current in the circuit from the trailer lights, brakes etc.
 
Lonewolf3165 said:
I think you are confusing resistance & current. .
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I'm not confusing a damn thing. Resistance at connections builds HEAT. The more the amperage in a circuit builds HEAT

It works exactly as I outlined. A loose/ corroded/ rusty fuse holder clip at a typical vintage fuse makes HEAT and this can be hot enough in a typical 20A fuseholder to heat up and blow that fuse just from the "normal" current of the circuit as well as the ADDED heat from the poor fuse clip connection. This might be ESPECIALLY true if a little more load has been added to the circuit, IE sealed beam halogen headlamps, or towing a trailer, so at least one more pair of stop/ tail lamps plus maybe some clearance lamps.

One huge clue that this might be happening with fuses is that many times you will have "nuisance" fuse failures, and they often will "blow" back "in the cap" where the separation is not visible.

The headlight breaker suffers from the same exact fate, and so do added breakers mounted TOO CLOSE to engine heat. Engine heat de-rates the breaker from the label rating.
 
67Dart273 said:
I'm not confusing a damn thing. Resistance at connections builds HEAT. The more the amperage in a circuit builds HEAT

It works exactly as I outlined. A loose/ corroded/ rusty fuse holder clip at a typical vintage fuse makes HEAT and this can be hot enough in a typical 20A fuseholder to heat up and blow that fuse just from the "normal" current of the circuit as well as the ADDED heat from the poor fuse clip connection. This might be ESPECIALLY true if a little more load has been added to the circuit, IE sealed beam halogen headlamps, or towing a trailer, so at least one more pair of stop/ tail lamps plus maybe some clearance lamps.

The headlight breaker suffers from the same exact fate, and so do added breakers mounted TOO CLOSE to engine heat. Engine heat de-rates the breaker from the label rating.
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Settle down dude!! I agree with you that poor/loose/corroded connections cause resistance & therefore heat. But added resistance in a circuit reduces current(amperage). The trailer scenario creates additional load because it's a parallel circuit added & due to the added demand for power(wattage):sign7: causes the amperage to increase. The fuse (assuming the circuit is good w/ no additional resistance from poor connections etc) is the weak link in the system with the highest resistance & blows, or in reality melts inside itself. A poor connection at a headlamp or a switch isn't going to cause a fuse to blow. Poor connections don't increase current. You can actually have more heat at the point of highest resistance but actually have less current flowing in the circuit.
 
Lonewolf3165 said:
A poor connection at a headlamp or a switch isn't going to cause a fuse to blow. Poor connections don't increase current. You can actually have more heat at the point of highest resistance but actually have less current flowing in the circuit.
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I don't dispute this, but that is not what I SAID, and I think you are confusing the issue.

When I mentioned the light switch I was referring specifically to the built in breaker. A bad connection at the harness connector, at the switch contacts, or in the breaker contacts themselves builds HEAT. I never said a thing about CURRENT. The HEAT generated by the bad connections can and does thermally conduct to the breaker, and this added HEAT caused by the bad connection(s) can cause the breaker to trip. The breaker is not tripping from too much current, it is tripping from the added heat.

The only factor concerning CURRENT in this type situation is that the HEAT from the bad connection thermally heats the breaker or the fuse, and DERATES the rated current of the device. Thus the device blows/ trips at a LOWER amperage than it's rated.

I have found this mechanism of failure in countless situations, typically older "rigs" with added snowplows, trailer brakes, trailer lights, etc. But it ALSO occurs in completely stock vehicles, typically one which has suffered some driver compartment water leakage, and therefore corrosion/ rust in the harness connectors/ switches/ etc.

After having spent a few years working on (locally) typical heat pump/ electric backup combos, you find this problem in electric furnaces commonly. The question becomes "which came first" the bad connection, or the heat which caused the connection to be damaged?

Very, very common to find damaged connectors, thermal protectors, and thermal control relays, and this is one reason I'm so "down" on Mopar bulkhead connectors, because those flat spade quick connects fail even at the 20A or so that a typical furnace element draws

These things

yuanfang_140251004_s.jpg
 
"It works exactly as I outlined. A loose/ corroded/ rusty fuse holder clip at a typical vintage fuse makes HEAT and this can be hot enough in a typical 20A fuseholder to heat up and blow that fuse just from the "normal" current of the circuit as well as the ADDED heat from the poor fuse clip connection."
Perhaps I mis-read this then. I would think though, the fuse or breaker is more likey to blow from current than the heat transfer of the connections. You would have a lot of melted switch & connector along the way to get it that hot. I 100% agree these old electrical systems are full of poor connections & trouble waiting to happen.
I hope you don't take my comments the wrong way. I've seen many of your comments that I'm sure help an awful lot of members with their electrical woes. Usually after reading them I agree & don't bother commenting because you say pretty much what I'd add anyway. It's all in the spirit of helping out.
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