Circuit Breaker Problem

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I am happy to report my '68 300 is back home! running great with the rebuilt engine, rebuilt transmission, and new brakes...BUT, I am having some electrical issues.

The brake lights were not working...$6 stoplight switch from the local Napa, problem solved! But that only last a little while. Now I have no tail lights, no head lights, and the windows won't move. It looks like the fuses are all still intact. Could this be a circuit breaker problem?

I have the FSM which tells me where the circuit breaker is behind the left front cowl and I do have a multi meter and will try see what the voltage tells me. I hate to sound dumb, but are these circuit breakers like the ones in my home where I can reset them, or do I have to find new ones? If I have to find new ones, where do I look? Thank you all in advance for your sage advice.

Dean
 
Dean,

No, that circuit breaker is not like household breakers. They are a sealed unit like a relay and typically automatically reset. That circuit breaker may only be for a power seat if your car has that.

The first thing I would do is check the bulkhead connectors on the firewall to make sure that they are not corroded. Good luck.
 
There are a few circuit breakers, depending on how the car is equipped. One breaker is for the windows, one for door locks, one for the top etc. The headlight switch has a circuit breaker built into it.

All automatically reset and there are none that control everything.

An "off the cuff" diagnosis would be to look at the fusible link under the hood first and follow the wire down into the bulkhead connector. One thing that you need to remember is enough current can pass through a fusible link to show on a voltmeter, but not enough current to operate anything else.
 
FURYGT said:
Dean,

No, that circuit breaker is not like household breakers. They are a sealed unit like a relay and typically automatically reset. That circuit breaker may only be for a power seat if your car has that.

The first thing I would do is check the bulkhead connectors on the firewall to make sure that they are not corroded. Good luck.
Click to expand...

Since you have a multimeter, also check to see if you are getting power to the fuse block. You can test the "hot" end of the fuse to the tail lights for power, next span the two metal tabs of the fuse with a test light or a continuity tester. If the test light lights when spanning, the metal fuse holder tabs are corroded and need to be cleaned or the fuse is bad. You could also have a bad light switch. If the internals of the switch are corroded, it might not be completing the circuit. Try removing one of the tail light bulbs and turn on the light switch. Test for voltage. If you get none, you have either a bad fuse, switch or the bulkhead connector is corroded.

The head light circuit is protected by a circuit breaker inside of the light switch. Sometimes these trip and do not reset. If that happens you need a new light switch. The dimmer switch on the floor might also be bad. Turn on the headlights and see if you are getting power to the dimmer switch. If you are not getting power to the dimmer, most likely your light switch is bad. Before replacing the light switch, test the hot input lead to be sure it is getting power to the switch.

As you have multiple electrical system failures, it is also possible that the power strip on the back of the fuse block is corroded so that the individual fuse clips are not making contact or there there is something bad wrong with the input power to the fuse block. Check these things and report back.

Dave
 
My question would be "What does work?" OR is everything "dead"?

The bulkhead connector is a little-considered item that's supposed to be reasonably sealed up, but over time, the terminals can get gunky in there from normal temp swings/condensate.

When I put the MP electronic ignition kit on my '67 Newport, all worked fine. I started it several times and no problem . . . until the 5th start attempt . . . nothing. I checked the voltage to the starter relay, and it was "there". Checked the voltage to the ignition switch (inside) and it was "there". But "no start". I got a new starter relay. No change. Then I looked a little farther at the battery terminals. At first glance, they looked fine, but on closer inspection, there was a thin layer of accumulation I could see between the cable end and the terminal post. I pulled the positive cable end off and it had a thin layer of accumulation. I got a battery post cleaner brush (one of the "What am I going to do with that?" door prizes at another Mopar club's road rallye several years prior) and cleaned the posts and terminal ends. Immediate starts after that, until the red wire on the inside of the bulkhead connector (going to the ign switch) got loose and fell off.

Apparently, the grunge on the post was letting voltage through, but not amps to make things happen?

As the engine and trans and other things were "R&R'd", you might check the wiring harness grounds for the light harness (each side, front and rear), for good measure.

Please keep us posted.

CBODY67
 
Big_John said:
There are a few circuit breakers, depending on how the car is equipped. One breaker is for the windows, one for door locks, one for the top etc. The headlight switch has a circuit breaker built into it.

All automatically reset and there are none that control everything.

An "off the cuff" diagnosis would be to look at the fusible link under the hood first and follow the wire down into the bulkhead connector. One thing that you need to remember is enough current can pass through a fusible link to show on a voltmeter, but not enough current to operate anything else.
Click to expand...

This is a little down the rabbit hole, but a good illustration of things that can happen when "nothing works". In 1972 the dealership I worked at sold two shiny new '72 fury's to a local truck stop as executive cars. A couple of months later one of them came back on the hook with electrical issues, battery dead, won't start. I opened the hood, fusible link obviously burned out "smoked". Installed a new fusible link. Car would turn over but not start. Installed a new point set, they were burnt. Car now started. Charging system did not work. Both the alternator and regulator were also shot. Replaced those items. Car now would now run and start and charge itself. Radio, all lights and blower motor did not work. Power to all items. Replaced radio, all light bulbs (burned out) and also replaced heater blower "open", smelled burnt. Gas gauge and temp gauge both did not work. Replace fried voltage limiter.

Service manager saw the time sheet and parts list. "This can not possibly all be wrong on the same car" was his response. I let him look at the "warranty" parts for himself. Somewhat irate he called the truck stop service manager who was a beer drinking buddy. "So what gives" he asked his friend. Response: "Executive type borrowed a battery charger and extension cord from the service bay. So what was so special about that? It was 24Volt." Enough said. Warranty claim denied. Never did figure out why the battery was dead in the first place, idiot probably left the lights on.

Dave
 
Last edited:
Owning a few 68's I will get right to the point on fixing the concern.
Never mind the circuit breaker in the kickpanel or the circuit breaker in the headlamp switch.
68 Chrysler's had ammeter gauge issues and when they short out,nothing works.
Check continuity at the ammeter gauge.

Run a jumper wire from the BATT stud at alternator to the BATT stud at starter relay. Use 10 gauge wire and 12 gauge fusible link at relay.
This feeds the hot side of the car (including feed for headlights,windows,etc) and takes 50% off the amperage load away from the ammeter gauge.
Ammeter gauges are HOT all the time and only a matter of time they burn out and you will have to walk.
Run another black wire with a fusible link from the BATT stud at alternator and feed it through the fire wall.
Pull the cluster and bolt it to the "discharge" side (black wire) of ammeter gauge.
This feeds the switched side of the car including the ignition switch and any accessories that needs the key on to work.
Now the ammeter gauge is bypassed and is used only as a solid connection point.
Next bypass the bulkhead altogether.
Using another fusible link at starter relay,run another wire from BATT stud at relay and run directly into the car to the red wire at ammeter guage.

You can cut the wire feeding the ammeter under the dash as a short cut but you will have to run another wire to feed the circuit breaker in the kick panel to run the windows and door locks (if equipped).

Three wires that will eliminate three weak points where you will never have trouble again.
Hopes this helps.
Any questions PM me. I am More than happy to help.
 
Last edited:
cbarge said:
Owning a few 68's I will get right to the point on fixing the concern.
Never mind the circuit breaker in the kickpanel or the circuit breaker in the headlamp switch.
68 Chrysler's had ammeter gauge issues and when they short out,nothing works.
Check continuity at the ammeter gauge.

Run a jumper wire from the BATT stud at alternator to the BATT stud at starter relay. Use 10 gauge wire and 12 gauge fusible link at relay.
This feeds the hot side of the car (including feed for headlights,windows,etc) and bypasses the troublesome fusible link at the bulkhead which goes directly to the ammeter gauge. Remember the ammeter gauge is HOT all the time and carries a huge amperage load that guarantees it will fail.
Run another black wire from the BATT stud feed it through the fire wall.
Pull the cluster and bolt it to the "discharge" side (black wire) of ammeter gauge.
This feeds the switched side of the car including the ignition switch and any accessories that needs the key on to work.
Next bypass the bulkhead altogether.
Using another fusible link at starter relay,run another wire from BATT stud at relay and run directly into the car to the red wire at ammeter guage.

You can cut the wire feeding the ammeter under the dash as a short cut but you will have to run another wire to feed the circuit breaker in the kick panel to run the windows and door locks (if equipped).

Three wires that will eliminate three weak points where you will never have trouble again.
Hopes this helps.
Any questions PM me. I am More than happy to help.
Click to expand...


Very good point. If you start the car and the ammeter needle moves to show a normal charge, it is probably ok for the moment. Mods suggested are a good idea in any case.

Dave
 
Just remembered...hot feed for the taillights go through headlight switch.
Brake lights get feed from turn signal switch.
Change headlight switch as a cheap alternative.
Remove kick panel and clean up the connector from dash harness that plugs into rear body harness.
Check for power going in and out of TS switch
 
cbarge said:
Just remembered...hot feed for the taillights go through headlight switch.
Brake lights get feed from turn signal switch.
Change headlight switch as a cheap alternative.
Remove kick panel and clean up the connector from dash harness that plugs into rear body harness.
Check for power going in and out of TS switch
Click to expand...


He has brake lights. See post 1.
 
cbarge said:
Just remembered...hot feed for the taillights go through headlight switch.
Brake lights get feed from turn signal switch.
Change headlight switch as a cheap alternative.
Remove kick panel and clean up the connector from dash harness that plugs into rear body harness.
Check for power going in and out of TS switch
Click to expand...
Yes, but power for the windows doesn't go through that headlight switch.
 
If the headlight switch is FUBAR..then upgrade the lighting system afterwards with this which will take all the load away from the replacement headlamp switch...
https://www.putco.com/heavy-duty-wire-harness-relay
Plug and play no hacking of wiring.
You do have to remove the low beam headlights to install the harness.
Hope this helps.
 
Davea Lux said:
This is a little down the rabbit hole, but a good illustration of things that can happen when "nothing works". In 1972 the dealership I worked at sold two shiny new '72 fury's to a local truck stop as executive cars. A couple of months later one of them came back on the hook with electrical issues, battery dead, won't start. I opened the hood, fusible link obviously burned out "smoked". Installed a new fusible link. Car would turn over but not start. Installed a new point set, they were burnt. Car now started. Charging system did not work. Both the alternator and regulator were also shot. Replaced those items. Car now would now run and start and charge itself. Radio, all lights and blower motor did not work. Power to all items. Replaced radio, all light bulbs (burned out) and also replaced heater blower "open", smelled burnt. Gas gauge and temp gauge both did not work. Replace fried voltage limiter.

Service manager saw the time sheet and parts list. "This can not possibly all be wrong on the same car" was his response. I let him look at the "warranty" parts for himself. Somewhat irate he called the truck stop service manager who was a beer drinking buddy. "So what gives" he asked his friend. Response: "Executive type borrowed a battery charger and extension cord from the service bay. So what was so special about that? It was 24Volt." Enough said. Warranty claim denied. Never did figure out why the battery was dead in the first place, idiot probably left the lights on.

Dave
Click to expand...
Bet he also hooked the charger up backwards.
 
Thank you all for your input.

A couple of clarification points:

The brake lights only worked for a short time. They are out now.

The car does start and run.

I will start with the multi meter at the battery and work my way to the bulk head.

Hopefully something will reveal itself early on. I am a big dude and did not enjoy being under the dash for that stop light switch. Hopefully I can avoid that again as much as possible.

I’ll keep you all posted.
 
OK...Feed to headlamp switch..hot all the time..
Feed to Brake light switch.. hot all the time..
Main red wire from starter relay going into bulkhead with fusible link feeds EVERYTHING inside the car including the both mentioned AND ammeter gauge.
Pretty simple and do not overthink the diagnostic process.
 
SPF Required said:
Hopefully something will reveal itself early on. I am a big dude and did not enjoy being under the dash for that stop light switch. Hopefully I can avoid that again as much as possible.
Click to expand...

Take the front seat out if you are going to be under there for any length of time.
 
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