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Discussion Starter #1
74 Nova ... My dash lights are very dim and my wipers only work when I open my driver's door. Only add ons are my after market tachometer, pod of water, volts, oil & toggle switch for electric fans (dual relays). Mind you its been working fine for over 10 years. Any and all suggestions will be truly appreciated.
Thanks In Advance.
 

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That sounds like you might have a bad ground connection for the dash wiring.

The dash wiring harness has several black ground wires (one for the wiper switch, one for the headlight switch, one for the dash cluster, etc). They all come together at a common splice inside the harness and then connect to ground via a ring terminal screwed to the car body. I can't remember the exact location of that ground screw but I think it's up under the dash somewhere on the driver side. A loose / corroded connection there could explain part of the issue you're having.

As for the wipers only working when the driver's door is open, that could also be related. The door jamb switch (that operates the dome light) is on the ground side of the circuit. So it provides a ground when the door is opened. It's not tied directly to the wiper circuit, but it does connect to the headlight switch. And if the headlight switch knob is turned fully counterclockwise, it creates a connection between that dome light switched ground and the black ground wire in the harness. So that could provide an alternative ground path for the wipers when the door is open.
 

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Discussion Starter #3
Thank You Ray for the reply. I'll search for a ground ring terminal that connects all three switches. If you happen to recall where on the driver under dash side the ring terminal maybe it truly will be appreciated.
 

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You're welcome!

I want to say that ground connection is somewhere over near the parking brake pedal assembly but it's been so long since I've done any work up under the dash on my 74 that I can't remember for sure.

The ring terminal you'll be looking for will only have 1 black wire. That wire leads back to a factory splice (hidden inside the harness), and the other black wires branch off from there to go to the various switches, cluster, etc.
 

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I'm in agreement with Ray in that there is a single 1/4" female ground connector that plugs into a tab on the back of the instrument panel and this wire then goes into the loom and then a ground wire comes out of the loom and attaches down by the bolt holding the emergency brake assemble under the dash.

The below is a picture of a 74 harness I modified to work with an original tach, on the right side and to the left above the rectangular plug for the instrument panel is the single 1/4" female connector to plug onto the tab of the instrument pane and then lower on the right side covered in masking tape is the ground wire end that attaches by the emergency brake assembly bolt.



I'm pretty sure the wire and terminal for under the dash is a ring terminal and is attached with a 1/4" hex headed screw.

If you have any jumper test wires with alligator clip ends you can try grounding the metal of the backside of the instrument panel to a ground under the dash and see what happens.

While I wonder what is going on with certain things happening when only the driver's door is open, it could very well be a circuit trying to find a ground through something else but then I wonder with the door open could something be flexing and causing issues. Maybe open the door and see what is happening and then with a finger push in the domelight switch and see what might have changed.

Jim
 

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Discussion Starter #6
First & Foremost Thank You for the AWESOMENESS ADVICE. I found the hex screw right where you said & the ground wire from the harness I reattached with new ring terminal and EVERYTHING is working normally
ThankYou ThankYou ThankYou??
 

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