Help with no headlights. 1974 scamp. Blinkers come on instead...

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Caco2120

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Looking for some help please.
Im far from a wiring expert, or an electrical guy. I know the correct thing to do is start tracing wires...but hopefully someone has more help than "get a diagram''

So i pull out the headlight switch, and i get no headlights. But...front markers come on, and so do blinkers, but lit up solid.
Also have no blink on the blinkers.

I did change the high/low beam switch. No change.

Could my headlight switch be the culprit?
 
Most likely thing is poor grounds. There is a major ground "somewhere" up front at the radiator support that grounds the headlights. And, the park/ signal lamp sockets may not be grounded.
 
Get a test light and probe the connector at the dimmer. Green wire should be hot with switch on.

A relay kit is a smart upgrade on these cars too. :)
 
Get a test light and probe the connector at the dimmer. Green wire should be hot with switch on.

A relay kit is a smart upgrade on these cars too. :)
What do those run? Plug and play?
If i have power at the green wire does that mean my headlight switch is ok?
 
If i have power at the green wire does that mean my headlight switch is ok?
Basically yes. And if so, then check for power at the headlights themself.
Power for the headlights goes into the headlight switch and then out to the dimmer switch.
The circuit breaker for the headlights is in the headlight switch.
Power for the parking lights goes to the fuesbox, then to the headlight switch and out to the lights.

but lit up solid.
Also have no blink on the blinkers.
That's an interesting clue. It might be a seperate problem, but maybe not.
Parking light position should turn on all side markers, tail lights and the front parking lights.

Turn signal and flasher arrangements varied for different years, so I hesitate to generalize.
Do a few a checks.
Headlights off, ignition switch in run, do the turn signals work normal?
Headlights off, switch can be off, do the 4 way flashers work?
(At least some years, stepping on the brake will stop the 4-ways,)
 
Front lighting ground at radiator support would be my guess also. When the front park/turn fixtures loose chassis ground, park lamp current will back feed through turn circuit to light up the little indicators in the inst' panel.
 
Power to all three dimmer light wires with switch on...not just the green.

Checked radiator support. Driver side has an obvious ground that comes from the headlight harness. I checked both the bolt, and probed the wire. Its grounded. I have a block and battwry ground on firewall also.

Started pulling gauges to see if headlight switch is fried. I see i get to stand on my head, drop the column (which i hate) to get the cluster out.

Awesome. Stopped for the night.
 
You don't need to pull the entire inst' panel to R&R the headlight switch.
 
You don't need to pull the entire inst' panel to R&R the headlight switch.
I took the philips screws out, and it had almost zero wiggle room. I see i can get the switch plug off, but dont see how i could change it with an inch of clearance. What am i missing?
Thanks for the enlightenment. New at this
 
There should only be power on the green wire if it's disconnected and either the red or violet if plugged in.

Showing power on all three at plug sure sounds like a missing ground or a series of them. That's smells of bleed back looking for a ground.
 
I took the philips screws out, and it had almost zero wiggle room. I see i can get the switch plug off, but dont see how i could change it with an inch of clearance. What am i missing?
Thanks for the enlightenment. New at this
Remove negative battery cable. There is one screw holding the fusebox in the way. You may not need to move that ( I do ). Pull headlight switch to full on. There's a small button on bottom or right side of the headlight switch. Push button to release knob/stem and pull it the rest of the way out. Remove switch bezel nut. Switch should maneuver out from under dash with harness connector on it.
 
There should only be power on the green wire if it's disconnected and either the red or violet if plugged in.

Showing power on all three at plug sure sounds like a missing ground or a series of them. That's smells of bleed back looking for a ground.
I found a short at a headlight connection once ( back of the left bulb ) that powered all at the same time. Dimmer switch seemed inop as the bulbs were higher beam regardless. They did work though. Has anyone considered blown out bulbs here?
 
I found a short at a headlight connection once ( back of the left bulb ) that powered all at the same time. Dimmer switch seemed inop as the bulbs were higher beam regardless. They did work though. Has anyone considered blown out bulbs here?
Considering all my turn signal indicators and fenders light up with the headlight switch...no...i hadnt considered bad headlight bulbs. I do agree with some kind of short, or backfeed.

Was thinking the headlight switch was my best starting point.
 
Remove negative battery cable. There is one screw holding the fusebox in the way. You may not need to move that ( I do ). Pull headlight switch to full on. There's a small button on bottom or right side of the headlight switch. Push button to release knob/stem and pull it the rest of the way out. Remove switch bezel nut. Switch should maneuver out from under dash with harness connector on it.
I will try that thanks. U are saying the knobs pull out the front? With depressing a switch?
 
There should only be power on the green wire if it's disconnected and either the red or violet if plugged in.

Showing power on all three at plug sure sounds like a missing ground or a series of them. That's smells of bleed back looking for a ground.
I did it with it still plugged in...should i have done it with the plug off? Switch killed power to dimmer, but deff had power at all 3 when pulled out all the way.

You still think i have a bad ground somewhere in the bay vs a shorted switch?

Would there be a butt connector up under the dash i bumped?
 
I will try that thanks. U are saying the knobs pull out the front? With depressing a switch?
Yes but it can be hard to depress the 'button' to release it.

I'd not start in the middle. There's only one hot going to the dimmer switch. I'd look down stream first to figure out why both hi and low have power at the same time.
 
It may be a cross wire short.
Redfish mentioned earlier about "backfeeding" of turn signal with loss of ground. Normally the power flows to ground if the circuit is complete. But the easiest path removed, it can flow through the instrument panel bulbs.
 
Update...
Im baffled. Pulled cluster all the way out. The little lights are all loose, and literally fell out.
So...i examides switches, panel, etc. Nothing fried, or melted. Moved on to tying the ammeter wires together to do some testing.

Get this. Blinker lever lights up both front fender indicators. Lights up the grille light dim on the respective side. Taillight lights solid bright. But no flash at all.

Pulled dimmer switch back out. I have grounds on both outzide wires. Nothin in middle. With switch unplugged. With switch plugged in, still got nothing. And wth is this lol. Interlock? Czn i remove it? This other 2 prong plug has a hot side...
So no closer to my no headlight problem

20190417_184350.jpg


20190417_184230.jpg


20190417_184426.jpg
 
Pic 3 is a bad pic, but thats the only wire i can find that is disconnexted.
I think the blue box is the old seatbelt interlock. I assume i can just unplug it.
That wide dual plug...idk what it is.
Black wire is bared, but made no difference when grounded.

Do the headlights run through the bulkhead plugs? I have some ugly wires on the passenger side plug...but if im reading the "mymopar" diagram right, those arent for the lights.
 
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Do the headlights run through the bulkhead plugs? I have some ugly wires on the passenger side plug...but if im reading the "mymopar" diagram right, those arent for the lights.

Yes. functional path is................

From splice in the black ammeter wire..........to the headlight switch........through the switch......out on the headlight supply terminal on the switch..........to the dimmer switch.......out the dimmer switch on either high or low beam feed (two wires)..........through the bulkhead.........to the front headlight harness.

What do you have for a shop manual/ diagram?
 
You need to learn to make electrical tests. You need a factory service manual, which you can download from MyMopar along with aftermarket diagrams. For troubleshooting you need some alligater clip jumper wires, a 12V test lamp and a multimeter.
 
Key points to check is start with the dimmer switch as it's easy to access. With power in the car, (dome light on?) and headlight switch on, two of the three dimmer terminals should have power. If not, backtrack towards the light switch. If so, see if you have power through the appropriate bulkhead feedthrough terminals. If you have power there, pull one headlight and check right at the lamp connector.
 
This is what im looking at.

http://www.mymopar.com/downloads/1974/74DartA.jpg

So with my cluster out entierly, and the 2 ammeter wires tied together, my blinker issue persists. U would say that eliminates the headlight switch...

With the cluster out, and the dimmer switch unplugged, the dimmer switch plug has grounds on the outer.

I see in the diagram that the driver side bulkhead has several headlight wires running through it.

I will probe them and see what i can find. Am i dumb to assume "red" is hot on that plug...so sending power to that wire should turn on the lights?

And the blue thing in my pics above...thats the seatbelt interlock right? Can that box just be removed?(unplugged)
 
Key points to check is start with the dimmer switch as it's easy to access. With power in the car, (dome light on?) and headlight switch on, two of the three dimmer terminals should have power. If not, backtrack towards the light switch. If so, see if you have power through the appropriate bulkhead feedthrough terminals. If you have power there, pull one headlight and check right at the lamp connector.
Yes, have dome light.
Have everything else in the car working besides front lights, and the turn signal blinkies.
 
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