Dash lights blink with left turn signal

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Canuck Bryan

Canuck Bryan

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Ok - here goes.

1971 Plymouth duster.

I was wiring in my after market gauges last night by splicing into the original instrument cluster harness.

The light green wire was the only wire which got power from switching the headlight switch on - so I thought great - this is for my dash lights! Well as I was trying to figure out which wires were for the signal light indicator (found right turn easy enough). Issue came in with the left turn - the only wire which power was going on / off / on etc. to was the same light green wire which is powered up when the headlights are on.

Left turn signal works until I turn the headlights on - then it is on, but not flashing. I wired in the gauge lights (using the light green wire), and they come on with the headlights as required. With the headlights, and now dash lights on - if I activate the left turn signal, the signal lights come on and stay on (don't blink), but the dash lights blink.

Am I missing something with this light green wire being hot with the headlight switch on, and intermittent (power switches on/off/on in time with the flasher) with the left signal on.

The original temperature sender and oil pressure sender leads are not connected to anything (as I went to mechanicals), and there is an orange with yellow tracer wire that I cannot figure out what is for.

Any help or thoughts would be greatly appreciated.

Thanks,
Bryan.
 
YOU LOL, are a guy who needs a service manual!!!!!

Go download one here, free

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617

More manuals and more stuff here

http://www.mymopar.com/index.php?pid=31

and from the same site, simplified, sometimes incomplete but easier to follow wiring diagrams. They do NOT show all options and connectors

http://www.mymopar.com/index.php?pid=18


"Light green" since the beginning of time has been one turn signal color in Mopars

And, the one at the HL switch is the headlight power going OUT of the HL sw to the dimmer switch

. The wire under the dash which feeds all dash dimmer controlled dash lights is ORANGE an starts at the fuse box INST fuse. This is usually the small amperage fuse all the way to one end of the box.
 
Yeah - I've got the service manuals and the "simplified" wiring diagrams - sometimes they are just difficult to follow.

If the light green is solely the turn signal, then why does it get power when the headlights come on? Also, with no gauges connected turning the headlights on "freezes" the left signal.

The only orange wire going into the connector has a yellow trace on it and it does not get power when the headlight switch is on.

As I mentioned the only wire that gets power when the headlights are on is the light green, and this is also the only one that gets power when the left signal is on.

So I am guessing somewhere along the line the green wire is connected in where the orange wire should be?
 
Well there might be TWO different light green, one is headlight power, TO the dimmer switch.

You've got something cross--connected or ungrounded, one or the other
 
Sounds dumb, but mine did the same thing. My buddy told me to look for a burned out bulb because the resistance change can cause that. I thought he was talking out his ***, but my left rear sidemarker was burned out. I changed it and the problem went away. I couldn't believe it.
 
You've got 2 separate problems.
Dash illumination wires are orange.
The green wire is turn. The reason it shows hot when the headlight switch is pulled to the park lamp position is a lack of ground at that front grill mounted fixture.
I can imagine how this could make the unknowing scratch head until blood flows.
The more common scenario is a post stating one or both turn indicators come on with park lamps. Anyway... Go find and correct the fixtures grounds to radiator support.
 
Backfeeding through the circuit & w/ headlamps on the hot wire is taking away that ground. In other words you've got an interruption in the ground side & it's finding it's way back through the circuit & then with the headlights on the positive side of the circuit now energized takes away that path to ground. You can't have 2 positives in a circuit.
Also look for incorrect bulbs in your turn signals & tail lamps.(Like a single filament bulb in a double filament socket)
 
I hope you fix your problem Bryan, but thanks to Mopar to ya mine is fixed my right turn dash light came on every time I honked the horn, I replaced my burned out front pass side marker light now it don't.

Jeff
 
So problem solved - it was a faulty headlight switch. Figured it out by testing the resistance of the tan wire at the switch to the orange "instrument light" wire - they were connected. Then I tested the resistance across the switch from the power to the tan wire post - nothing. Resistance from the power post to the headlight post was over 200 ohms. Replaced the switch and viola - everything works as it should. I did start out by checking bulbs and grounds as suggested so it simply became a game of elimination.
 
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