Large-scale Duster electrical issue

[Tylan]

This may be a little large for one post but, I recently got a '74 Plymouth Duster that starts, runs, and moves great; however, none of the dash lights (instrument panel, gear indicator, climate control, radio), turn signals, or brake lights work properly. While I was messing around with the wires and studying my service manual for hours, I've discovered the following:

Headlights are functional.

Reverse lights work.

Hazard lights work on the front and on the dash, but not in the rear.

A previous owner had removed the capacitor, aka flasher, for the turn signals and spliced the red and black wire together (I explored this further by temporarily separating the wires and putting the flasher for the hazards in between the wires. This resulted in the flasher - as well as the ignition coil? - constantly clicking whenever the key was in the run position. Also, before I had done this test, moving the turn signal stalk did nothing, but with the flasher connected to the red and black wire, I could hear another clicking sound from the passenger side whenever I flicked the signal stalk either direction.)

There are two pink wires that turn into one wire through a harness going to the tail lights, the connector of which in the harness was heavily corroded and broke when I disconnected the harness, so I cut the pink wires from the harness and spliced in a new connection.

I tested the brake lamp switch for continuity and there is indeed continuity.

I cleaned up the circuit board on the back of the instrument cluster and there is continuity all across.

There is a white harness near the steering column that has had one thick red wire burn up in it, a previous owner had bypassed the harness by splicing the wire together.

I replaced all 6 fuses and checked the top of the fuse block for major corrosion, nothing bad enough to halt the flow of electricity.

There is a small connector located near the wiper switch (wipers don't work either btw) consisting 4 wires forming into 2 connectors, 2 orange and 2 yellow. This has always been disconnected for as long as I've had the car.

There is another loose connector that has 2 blue wires with white tracers sort of above the harness going to the tail lights.

A T shaped connector with a dark green wire and brown wire is hanging under the glove box.

Sorry for the long post, I seriously appreciate the help!

 

[Tanker]

Those are some seriously rotten looking connections. If you plan to keep that harness I’d start by cleaning all of that up.

 

[Tylan]

Those are some seriously rotten looking connections. If you plan to keep that harness I’d start by cleaning all of that up.

You're probably right about that, but I'm not sure its the source of the problem. They seemed to be clean enough when I probed them with my multimeter.

 

[crewchief]

This may be a little large for one post but, I recently got a '74 Plymouth Duster that starts, runs, and moves great; however, none of the dash lights (instrument panel, gear indicator, climate control, radio), turn signals, or brake lights work properly. While I was messing around with the wires and studying my service manual for hours, I've discovered the following:

Headlights are functional.

Reverse lights work.

Hazard lights work on the front and on the dash, but not in the rear.

A previous owner had removed the capacitor, aka flasher, for the turn signals and spliced the red and black wire together (I explored this further by temporarily separating the wires and putting the flasher for the hazards in between the wires. This resulted in the flasher - as well as the ignition coil? - constantly clicking whenever the key was in the run position. Also, before I had done this test, moving the turn signal stalk did nothing, but with the flasher connected to the red and black wire, I could hear another clicking sound from the passenger side whenever I flicked the signal stalk either direction.)

There are two pink wires that turn into one wire through a harness going to the tail lights, the connector of which in the harness was heavily corroded and broke when I disconnected the harness, so I cut the pink wires from the harness and spliced in a new connection.

I tested the brake lamp switch for continuity and there is indeed continuity.

I cleaned up the circuit board on the back of the instrument cluster and there is continuity all across.

There is a white harness near the steering column that has had one thick red wire burn up in it, a previous owner had bypassed the harness by splicing the wire together.

I replaced all 6 fuses and checked the top of the fuse block for major corrosion, nothing bad enough to halt the flow of electricity.

There is a small connector located near the wiper switch (wipers don't work either btw) consisting 4 wires forming into 2 connectors, 2 orange and 2 yellow. This has always been disconnected for as long as I've had the car.

There is another loose connector that has 2 blue wires with white tracers sort of above the harness going to the tail lights.

A T shaped connector with a dark green wire and brown wire is hanging under the glove box.

Sorry for the long post, I seriously appreciate the help!View attachment 1715588306 View attachment 1715588307 View attachment 1715588308 View attachment 1715588310 View attachment 1715588312 View attachment 1715588313 View attachment 1715588314 View attachment 1715588316 View attachment 1715588317 View attachment 1715588327

If that was mine, I would replace it all with new harness. You never know who has been behind the dash doing god know what. You will be far better off with fresh wiring.

 

[Mattax]

You're probably right about that, but I'm not sure its the source of the problem. They seemed to be clean enough when I probed them with my multimeter.

A multimeter isn't sensitive enough to measure resistances that will cause voltage drop when the normal operating current flows through.
So I would still clean that up. There's at least one thread here about ways to clean the terminals in the fusebox.

I do agree that is probably not the cause of the instrument lights not working.
The instrument lights have their own fuse after the headlight switch.
So they work as follows: Power from mainsplice to fusebox. Fusebox to headlight switch B2 terminal. This also powers parking lights. Headlight switch to fusebox 2 or 3 amp fuse. From there to instrument and radio lighting.

Brake lights and turn signals both work through the turn signal switch. So suspect switch or the column connector.

I'm also going to suggest doing a search for a thread on Chrysler terminals and also one for open barrel crimpers. Those packard and molex terminals are really better than the closed barrel ones from the parts stores or Harbor Frieght. They make a better connection and provide better support for the wire.

Last but not least, the flasher unit is a bimetal that heats up and opens. Replacements are pretty readily available. The hazzard flasher is seperate. Different years wire the hazzard flasher and switch slightly differently, so I can't generalize on its connections.

 

[67Dart273]

If you don't do anything else, replace the fuse panel. The same folks who sell harnesses sell "universal" replacement fuse panels

The way to check for poor connections is with voltage drop measurements, not an ohmeter, as Mattox said.

Example........Let's "say" the headlights are dim

The functional path "generally" is this

Battery........starter relay "big stud" (junction)..........fuse link...........through the bulkhead connector (ammeter large red)..........through ammeter.......out on big black.........to under dash welded splice.........to headlights B1 terminal on light switch connector..........through connector..........to light switch.........through switch..........out of switch on headlights power conductor

From there to the dimmer switch.......out on either low or high beam...........through the bulkhead connector............out the headlight harness to the lamp connector.........through the lamp........to ground.

EACH one of those points separated by dotted lines is a point of possible poor connection(s) and they ADD. Let's say with lights on in high beam, let's say there is .2V drop across the headlight switch, and another .1V at the headlight connector leaving the switch, and then let's say there is .3V going through the bulkhead connector.

This adds up .2 + .1 + .3 total if there is nothing els, that is .4V. That means that if you stab a meter probe into the battery POS post, and get a firm connection right at the headlight with the other meter probe you will measure .4V. You can "backtrack" at each point that is easy to access, and "run down" the poor connection.

The other way to do this of course is measure at the battery post, and then at the headlight "to ground." In this case you would see there is .4V difference between battery and the healdlight. Now you would have to move back towards the source point by point and note each reading. it is much easier as you move along to just measure the difference.

It makes things easier to "rig" a long test wire which you can clamp direct to battery POS or NEG depending. You want a small fuse in line, and the wire long enough to reach the far end of the car (checking tail lamps, etc) Put a clamp and boot on each end, you can hook one end to the batt and the other to the meter.

You can buy various banana connectors and alligator clips off egag.

 

[Tylan]

Thank you all so much for your help, got the issue sorted out! Although it turns out I was just a little confused and overcomplicated the whole deal. It was just a bad flasher! (And some corroded connections as well) Also, the picture I have of what I thought where the flasher went was actually wires for the ammeter. ‍*Facepalm* That explains why the flasher I put there to test was constantly ticking with the key in run position. Oh well, gotta learn somehow right?

 

[crewchief]

Nice to see you worked it out. I would still replace that old wiring under the dash. Just a small piece of security, hate to see it burn up on you.

 

[yellow rose]

Thank you all so much for your help, got the issue sorted out! Although it turns out I was just a little confused and overcomplicated the whole deal. It was just a bad flasher! (And some corroded connections as well) Also, the picture I have of what I thought where the flasher went was actually wires for the ammeter. ‍*Facepalm* That explains why the flasher I put there to test was constantly ticking with the key in run position. Oh well, gotta learn somehow right?

So that fixed the instrument lamps? I’ve got a 73 Duster that the instrument lamps don’t work. I replaced all the bulbs, the printed circuit looks BFN and I can’t figure out WTH is going on.

 

[Mattax]

I *think* the turn signal flasher unit in 73 and 74 may still be in a clip near the ashtray. When its in the clip the sound is amplified a bit.
At least on the late 60's cars, the hazzard flasher is left of the lower steering column.

Hazard wiring changes over the years, but somehow it still needs to go to the turn switch to get to all the turn signals and indicators.
Late 60s it also is over riden by the brakes. I dont know if the changes or not.

Ammeter. With a few exceptions ammeter should only be connected in-line as part of the battery charge/feed wire.
Exceptions I can think of are clock, covertible top on the battery side some years.
If your '74 has or had an rear window defrost grid, then it may have the heavy duty wiring option.

 

[Tylan]

So that fixed the instrument lamps? I’ve got a 73 Duster that the instrument lamps don’t work. I replaced all the bulbs, the printed circuit looks BFN and I can’t figure out WTH is going on.

No, replacing the flasher wont help with instrument lamps. What happened to me was I basically just kept messing around with the wires and cleaning up any connections I could find (including dismantling the fuse block), then suddenly, as I turned the headlights on one day, I noticed my dash lights were on! I have no idea exactly how. However, the connection is a bit fragile, sometimes just tapping the lamp switch will turn off the dash lights. Also, for some reason, one of the back lights in the instrument panel is flashing instead of the actual signal bulb for both hazard flashers and turn signals. So in short, my dashlights probably weren't working because of corroded connections, I reccomend going through them and cleaning them up if you haven't already done so.

 

[67Dart273]

What that can be.....

1....The dash dimmer control is a rheostat which involves a mechanical wiper controlled by the knob rubbing against and making contact with a circular wound/ coiled resistance wire. That can get dirty/ corroded or loose. First thing to try is simply vigourously working the dimmer knob left/ right many times to see if it will "scrub" the connection clean

2....The one lamp not working may be loose connection(s) at the bulb socket, which has contact fingers that make when the socket is twisted into place. These and the PC board can get corroded and dirty

3...Last other wierd cluster problems can be caused by poor grounding. Some models have a two piece PC board, but in any case, clean the ground by rotating the mounting screws from PC board to the cluster housing loose/ tighten. Clean up the board contacts area for the lamps and bend and clean the lamp socket fingers and then ADD A GROUNDING pigtail wire which you will bolt to the column support or dash frame. The original ground was the cluster mounting screws, which is poor

While you have the cluster out, flow jumper solder over the PC board to contact fingers for the instrument regulator, which can fail and leave a no-connection, loosen/ and retighten the gauge studs several times.

Inspect the harness connector pins on the PC board and solder them in place. There used to be a good thread on here about repairing those

The politics withing photophucket has forever damaged the internet

67dart273, cluster repair - Google Search

 

[Tylan]

What that can be.....

1....The dash dimmer control is a rheostat which involves a mechanical wiper controlled by the knob rubbing against and making contact with a circular wound/ coiled resistance wire. That can get dirty/ corroded or loose. First thing to try is simply vigourously working the dimmer knob left/ right many times to see if it will "scrub" the connection clean

2....The one lamp not working may be loose connection(s) at the bulb socket, which has contact fingers that make when the socket is twisted into place. These and the PC board can get corroded and dirty

3...Last other wierd cluster problems can be caused by poor grounding. Some models have a two piece PC board, but in any case, clean the ground by rotating the mounting screws from PC board to the cluster housing loose/ tighten. Clean up the board contacts area for the lamps and bend and clean the lamp socket fingers and then ADD A GROUNDING pigtail wire which you will bolt to the column support or dash frame. The original ground was the cluster mounting screws, which is poor

While you have the cluster out, flow jumper solder over the PC board to contact fingers for the instrument regulator, which can fail and leave a no-connection, loosen/ and retighten the gauge studs several times.

Inspect the harness connector pins on the PC board and solder them in place. There used to be a good thread on here about repairing those

The politics withing photophucket has forever damaged the internet

67dart273, cluster repair - Google Search

Hmm, not sure why I didn't check the grounds before, I'll have to do that when I get the chance. Also, correct me if I'm wrong, but if the temp guage shoots all the way up as soon as I turn the engine on and fuel guage is terribly inconsistent with its readings, the issue is most likely a bad voltage limiter right?

 

[67Dart273]

Likely but not necessarily. Could be the wire is shorted (burned against a manifold?) so try disconnecting from the sender. But a bad IVR should affect both temp and fuel gauges if they were both working

Also you have a LOT of rust in the fuse panel, which might indicate serious leakage problems such as windshield or even (gag) rusted through cowling pan. Often, tho, the cowl fills with mud/ leaves/ etc which dams up drainage and caused water to overflow through the vent system