headlights

[kager67]

Hey guys I have a 77 Newport with 57,xxx miles and I'm having a problem with the headlights randomly quitting. It doesn't matter if its moving or parked. They work fine for the first 10 miles or so and then start going on and off. If I shut them off for a couple miles when I turn them back on they will stay on longer.

All the other lights on the car work perfectly when they quit, no dimming or flickering of dash,marker or brake lights. Acts just like a circuit breaker opening and closing but there isn't one for the headlights is there? I've felt under the dash and fuse panel and nothing feels hot or smells hot in the car. I've replaced the dimmer switch twice with no change. Kinda stumped here. My next thought was to replace the headlight switch but wiggling the switch doesn't make even a flicker in the lights. Car is currently at my buddies just looking for some advice when I get back to it. TIA

 

[Big_John]

There is a circuit breaker built into the headlight switch on your car.

So.... It sounds like you have either a bad circuit breaker (doubt it, but possible) or something in your headlight wiring has too much resistance or is shorting to ground and causing the breaker to trip.

My bet is too much resistance.... The circuit heats up, trips the breaker, cools down, resets the breaker etc.

I would start at the headlights and check all the connections for corrosion and if they are tight, including the grounds. That is the easiest place to get to. From there, the next step is the connector on the firewall. You'll have to figure out which wires they are (a FSM is your friend) and check them for corrosion and tightness. There's a good chance that is where your problem is. From there it's under the dash to the switch. Corrosion may not be an issue there, but it still needs to be tight.

I like to use De-Oxit (google it) to clean up the connections.

 

[Fury440]

I don't remember for '77, but if your dimmer switch is on the floor, check it first. They get full of dirt, water, crud and will short as the car bounces over bumps. That short will pulse the breaker and will heal itself until the next bump. If that's not your problem, look at the bulkhead connector for a dirty corroded terminal that is also subject to random make/break as you drive.

 

[kager67]

Curiosity got the better of me and I went out to check the car out. I didn't have a lot of time but I checked over the connections I could get to quickly and didn't find anything obvious, everything is clean and dry. Do these cars not have a bulkhead connector like the earlier cars do? All I could see was a cluster of wires running through a big grommet in the firewall. I've replaced many wiring harnesses in my other cars (b and e bodies) but this appears to be a different setup. I ran out of time before I could check the headlight switch but I'm leaning towards that being the problem.

 

[65sporty]

My first thought was the headlight switch, because of the circuit breaker like Big_John said.

 

[CBODY67]

On the non-Chrysler product I was driving at the time, I went to a mall to shop. When I came out, it was getting dark. I started the car and pulled the knob for the headlights. Nothing. Pushed and pulled again, no headlights. So I called a wrecker to take me home. It would be daylight when I went to work the next morning, so no headlights needed. Took it in to work and a work order was written. IF I'd tried the high beams, they would have worked, but I didn't. A $10.00 dimmer switch was the culprit. AND, after the tech cycled the dimmer a few times, it always worked, but it was replaced anyway.

Seems like one of the "improvements" of the '74+ C-bodies was a "swing down fuse block"? Possibly the bulkhead connector was replaced by that one item?

CBODY67

 

[commando1]

Do these cars not have a bulkhead connector like the earlier cars do? All I could see was a cluster of wires running through a big grommet in the firewall.

No bulkhead connector starting 74 and up. You are correct that it is all the wiring wrapped up in one humingous harness going thrugh the grommet. What you see coming from the other side of the grommet will amaze and astound you.

 

[kager67]

Thanks for the info guys. When I get back to it and have time to tear into the dash I'll let you know what I find.

 

[CBODY67]

Check that dimmer switch (still on the floor?) first!

CBODY67

 

[kager67]

Cbody67 I appreciate the reply but as I stated in my original post I have tried 2 separate dimmer switches with no change. Wiring down at the dimmer switch is also pristine. You could eat off the floors on this thing it was very well maintained.

 

[Snotty]

I have the same problem with mine. I think mine is the dimmer switch as it started in 2010 when I made a drive up the Kern River Canyon. Coming back at night and using my highbeams, they started to flash on and off. Been doing it ever since. I have a new switch but have not installed it to see if it will make a difference.

 

[CBODY67]

Just wanted to ensure you didn't embark upon an instrument panel expedition and later find you didn't really need to. C-body front floors are reasonably spacious, but still not the most comfortable place to be, from my own experiences.

Have you checked the bulkhead connector wiring terminals for unseen "accumulation" from age and such? Although they are usually "untouched", they can still be subject to decades of hot/cold cycles and degrading from minor condensation over these extended times, from experience.

You might also check Dr. Stern's headlight website. He has a way to run headlights via a relay that can result in more voltage to the stock lights, plus a way to wire a resistor into the later Chrysler wiring harness to us a '68 Chrysler voltage regulator on the newer models that run the voltage regulator through the computer. An interesting website. www.danielsternlighting.com

CBODY67

 

[commando1]

Have you checked the bulkhead connector wiring terminals

No bulkhead connector starting 74

 

[kager67]

Well, just to update a bit. I got the car in my garage and replaced the headlight switch. To test it I put a battery charger on it turned on all the lights. I left it for about 45 minutes while I worked on other things and no problems. Tonight I took it out on the road for a half hour or so and not as much as a flicker. Seems to be fixed. Thanks again for the advice and suggestions.

 

[CBODY67]

When I was digging around in some Chrysler factory service manuals earlier today, I found a rating on the circuit breaker in the headlight switch. 15amps. This was for a 1960 Chrysler, I believe. Not sure how that relates to "watts", which is how the headlights are rated. I think that 55-60 watts, depending upon low beam or high beam?

First time I heard of that circuit breaker was when people were trying to use landing lights for "driving lights". They'd trigger them as "high beams", then they'd go out for no reason . . . the circuit breaker was kicking in and out due to the additional load.

Glad it seems that your issues are over.

CBODY67

 

[Big_John]

When I was digging around in some Chrysler factory service manuals earlier today, I found a rating on the circuit breaker in the headlight switch. 15amps. This was for a 1960 Chrysler, I believe. Not sure how that relates to "watts", which is how the headlights are rated. I think that 55-60 watts, depending upon low beam or high beam?

First time I heard of that circuit breaker was when people were trying to use landing lights for "driving lights". They'd trigger them as "high beams", then they'd go out for no reason . . . the circuit breaker was kicking in and out due to the additional load.

Glad it seems that your issues are over.

CBODY67

To get the amperage, divide the total wattage by the voltage. I=P/V

If the bulbs were 55 watts each and 2 were on, that would total 110 watts. Divide that by 13.5 volts and you end up with 8.15 amps.

Here's an easy Ohms Law calculator.

Ohm's Law calculator