Short to ground. Please help!

[Walker Westover]

Hello everyone, I have a 1971 Dart I'm slowly restoring. I was attempting to restore the functions of the blinkers(new switch and flasher), when I realized I had a short to ground from the turn signal circuits. Front, rear, left, and right all short to ground. What is odd to me is that the hazard lights function as they should, head lights, dome light all function. No blown fuses aside from the radio. I disconnected the bulkhead connector, did a continuity test from ground to the pins on the firewall side. All of the wires for the blinkers are shorted out. I'm at a loss at this point, and really hoping to not have to take the whole dash apart. I'd appreciate any help at all. Thanks.

 

[67Dart273]

What do you mean "flashers?" And what do you mean "short to ground?" How did you determine this? EG If you checked from the lamps to ground they WILL suggest a short, as just one stop/ turn lamp filament is very low resistance.

If you are saying that the hazards operate and the turn signals do not, they actually use the same lamps, so they can't be shorted, UNLESS something in the switch is shorting them when the switch is centered

We need to know exactly what works and what does not and what lead you to the conclusion

 

[Walker Westover]

What do you mean "flashers?" And what do you mean "short to ground?" How did you determine this? EG If you checked from the lamps to ground they WILL suggest a short, as just one stop/ turn lamp filament is very low resistance.

If you are saying that the hazards operate and the turn signals do not, they actually use the same lamps, so they can't be shorted, UNLESS something in the switch is shorting them when the switch is centered

We need to know exactly what works and what does not and what lead you to the conclusion

Sorry, by flashers I ment hazard lights. I corrected it. If I take the connector apart at the end of turn signal switch. The pins that go to the turn signals read as having continuity to ground. The pins on the switch side of the connector don't have continuity to ground. The only things that I've noticed not working is the radio and turn signals. The wipers, heat, lights, dimmer switch, all work.

 

[67Dart273]

Continuity is normal. As I said the bulb filaments are quite low resistance. Bear in mind you have two flashers--one for hazard, one for turn

 

[Walker Westover]

Continuity is normal. As I said the bulb filaments are quite low resistance. Bear in mind you have two flashers--one for hazard, one for turn

There is also continuity from the power feed wire (the one with the fusible link from the starter relay) to ground. Would that be considered normal? I replaced the flasher behind the ashtray, I was under the impression that was the one for the turn signals.

 

[Walker Westover]

I should also add that the altnator is not hooked up to the ammeter. The connection at the bulkhead was literally melted before I got it.

 

[Mattax]

I should also add that the altnator is not hooked up to the ammeter. The connection at the bulkhead was literally melted before I got it.

My suggestion is to take a step back.
Lets start with the premise - a short to ground.
A serious short to ground in the turn signals or hazzard should cause the flasher unit to open like a circuit breaker. Hazzards were also always fused, turn signals were not. We'll have to look at the shop manual or operators booklet for '71 to know if they were fused that year.
A serious short to ground before the fusebox will cause the engine to stop running (if it was) and the fusible link to melt.
The fusible link is in the battery line - usually right at the bulkhead connector.

Even though the ammeter is labeled alternator it is not in the alternator line. Its in the battery line. It shows the flow of current into or out of the battery. If the battery is discharging when it should be charged, then the alternator is not supplying the power to the run car. In that sense its an alternator gage. A little confusing in terminaology. Just remember it shows Discharge and Charge.

Here's the basic layout.

Some details may be different. For example I think the hazzard flasher is on the same fuse as the brake light switch.
Go to www.mymopar.com and download the service manual.
You may wish to buy a paper copy as well but the digital pdf will get you going.

 

[Mattax]

Mymopar also has the Master Technicians series in pdf and the videos.
Howerver they don't have an index.
Imperial Club has an index.

Master Technician Service Conference - Chrysler's Training for Mechanics

The Imperial Mailing List Online Car Club is dedicated to the preservation, appreciation and restoration of Imperials and Chrysler Imperials of all years, models and body-styles.

www.web.imperialclub.info

There are a couple of pamphlets and videos explaning how the turn signals work and how to troubleshoot them and wiring in general. See for example 1965#2, 1968 #6 and 1967 #7

 

[Walker Westover]

My suggestion is to take a step back.
Lets start with the premise - a short to ground.
A serious short to ground in the turn signals or hazzard should cause the flasher unit to open like a circuit breaker. Hazzards were also always fused, turn signals were not. We'll have to look at the shop manual or operators booklet for '71 to know if they were fused that year.
A serious short to ground before the fusebox will cause the engine to stop running (if it was) and the fusible link to melt.
The fusible link is in the battery line - usually right at the bulkhead connector.

Even though the ammeter is labeled alternator it is not in the alternator line. Its in the battery line. It shows the flow of current into or out of the battery. If the battery is discharging when it should be charged, then the alternator is not supplying the power to the run car. In that sense its an alternator gage. A little confusing in terminaology. Just remember it shows Discharge and Charge.

Here's the basic layout.
View attachment 1716095238
Some details may be different. For example I think the hazzard flasher is on the same fuse as the brake light switch.
Go to www.mymopar.com and download the service manual.
You may wish to buy a paper copy as well but the digital pdf will get you going.

When I bought it, the altnator was hooked up to the bulkhead as it should be, a heavy gauge black wire. The power line fusible link was melted, I replaced the fusible link and disconnected the altnator, hooked everything else up as it was. No issues with the fusible link since.

 

[Sublime one]

When I bought it, the altnator was hooked up to the bulkhead as it should be, a heavy gauge black wire. The power line fusible link was melted, I replaced the fusible link and disconnected the altnator, hooked everything else up as it was. No issues with the fusible link since.

Pay close attention to @Mattax post. He will save ya! He has forgotten more than most of us know On electrical gremlins issues.

 

[67Dart273]

I would ditch continuity readings almost completely. They can really steer you wrong in a complex circuit. Instead, rig a large wattage lamp in series with the ground cable to troubleshoot. You can connect and disconnect various circuits to find the short

Use a headlamp or a stop/ tail lamp with both filaments parallel'ed. The lamp will keep stuff from burning down.

 

[Mattax]

Some of this is simple.

There is also continuity from the power feed wire (the one with the fusible link from the starter relay) to ground. Would that be considered normal?

Take a look at the diagram above. Trace along the power feed from the battery. With key off, is there a connection to any circuit?
Are any of those items on? For example is the door open? if the door is open the dome light circuit is complete. Close the door, or take the bulb out or the fuse out and its not.

With everything off, there should be no continuity to ground. Infinite resistance if you have a multimeter.
Additionally, read the ammeter!
If there are electrons moving in or out of the battery and through the ammeter, the needle will move. The more electrons flowing the more the needle deflects.
Full deflection in either direction indicates 40 amps and is a major problem. Disconnect the battery. Do not reconnect other than for trouble shooting as described above by 67Dart273. Or you can use the flasher unit as described in the Master Tech booklets and movies.

I replaced the flasher behind the ashtray, I was under the impression that was the one for the turn signals.

Correct.

The power line fusible link was melted, I replaced the fusible link and disconnected the altnator, hooked everything else up as it was. No issues with the fusible link since.

It's possible the short was in the alternator.
Easy check. The output stud of the alternator should be isolated from the alternator housing. ie No continuity from stud to the housings (end shields). Shop manual has some other easy checks.

No blown fuses aside from the radio.

Easy one here.
Go to the diagram and place your finger on the feed to the turn signal flasher. Follow it back.
Q. Where does it take you?
A.____________

Next.
Follow it further back to the key switch.
Those fuses on the Q2 feed are switched 'Accessory'. Items on switched accessory only work with the key in run or accessory positions.

The pins that go to the turn signals read as having continuity to ground. The pins on the switch side of the connector don't have continuity to ground. The only things that I've noticed not working is the radio and turn signals. The wipers, heat, lights, dimmer switch, all work.

You can now make two categories.
Equipment/lights with power feeds that are always hot.
Equipment/lights with power feeds that are only hot through the key switch.

 

[Mattax]

Side note:
Some multimeters have are capable of reading moderate current flow for short periods of time.
They will have a setting for 0-10 amps or something along those lines. They will typically have a fuse on that function.
Use this only when you are absolutely sure the current flow is less than the 10 amps or whatever it can handle.

Current is electrons moving. No movement = no current, therefore zero amperes.
Potential is electrons excited, looking to go somewhere. Voltage indicates energy level available at that location; either compared with ground, or another location if the second probe is someplace other than ground.

When there is a connection allowing a complete circuit the electrons move. Only then is there current flow. By accepted convention we describe this as current flowing from high voltage to the lower voltage.
A short is when the electrons find an easier, lower resistance path to back to ground.
An open is when there is a break in the circuit.

Your immediate problem with the turn signals is that there is a break in the feed line.
The cause may have been a short that caused the fuse to melt.

 

[Walker Westover]

Some of this is simple.

Take a look at the diagram above. Trace along the power feed from the battery. With key off, is there a connection to any circuit?
Are any of those items on? For example is the door open? if the door is open the dome light circuit is complete. Close the door, or take the bulb out or the fuse out and its not.

With everything off, there should be no continuity to ground. Infinite resistance if you have a multimeter.
Additionally, read the ammeter!
If there are electrons moving in or out of the battery and through the ammeter, the needle will move. The more electrons flowing the more the needle deflects.
Full deflection in either direction indicates 40 amps and is a major problem. Disconnect the battery. Do not reconnect other than for trouble shooting as described above by 67Dart273. Or you can use the flasher unit as described in the Master Tech booklets and movies.

Correct.


It's possible the short was in the alternator.
Easy check. The output stud of the alternator should be isolated from the alternator housing. ie No continuity from stud to the housings (end shields). Shop manual has some other easy checks.


Easy one here.
Go to the diagram and place your finger on the feed to the turn signal flasher. Follow it back.
Q. Where does it take you?
A.____________

Next.
Follow it further back to the key switch.
Those fuses on the Q2 feed are switched 'Accessory'. Items on switched accessory only work with the key in run or accessory positions.


You can now make two categories.
Equipment/lights with power feeds that are always hot.
Equipment/lights with power feeds that are only hot through the key switch.

Thank you! I really appreciate the help.