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Intermittent light issues
#1
We have been having all kinds of intermittent lighting issues.  The dash illumination blinks on and off.

The brake lights are the same way.  Sometimes they all 4 work, sometimes only 1 works, sometimes 3 work.

The headlights work flawlessly all the time, but the marker lights and grill lights come and go as well.

I dont think they are specifically related to each other because they dont all come on and go off at the same time.

Any hints of where to look would be much appreciated.

"I drank what?" - Socrates
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#2
Grounds or corroded bulb sockets



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#3
(01-06-2019, 06:12 PM)jowens1126 Wrote: We have been having all kinds of intermittent lighting issues.  The dash illumination blinks on and off.

The brake lights are the same way.  Sometimes they all 4 work, sometimes only 1 works, sometimes 3 work.

The headlights work flawlessly all the time, but the marker lights and grill lights come and go as well.

I dont think they are specifically related to each other because they dont all come on and go off at the same time.

Any hints of where to look would be much appreciated.

Could be dirty/corroded headlight switch contacts. The dash and parking lights all work off the same switch position. If I recall correctly, in the park light only position the A, B, R, P, I will all be "ON". Pull the switch all the way out and H will also be "ON".  You can use an Ohm meter to test the switch posts. I have taken the switches apart and cleaned the contacts and the sliding mechanism and they work better. They just have either a couple of metal tabs or rivets holding them together. There are a few moving parts inside so be sure to put it back together correctly.

Or just get a new switch, they are not all that expensive.

[Image: wiring-1970-mustang-headlight-switch-wir...iagram.jpg]
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#4
@rackerm

What do you have to do to replace the headlight switch? Is it readily accessible or do you have to pull the lower dash to get to it?


Edit:

Ok I found this thread that has all the info on removal.
https://www.7173mustangs.com/thread-head...ght+switch

I'm going to order a new one tonight.

"I drank what?" - Socrates
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#5
(01-07-2019, 11:06 AM)jowens1126 Wrote: @rackerm

What do you have to do to replace the headlight switch?  Is it readily accessible or do you have to pull the lower dash to get to it?


Edit:

Ok I found this thread that has all the info on removal.
https://www.7173mustangs.com/thread-head...ght+switch

I'm going to order a new one tonight.

First, pull the knob out to the headlight position and then while pressing the little rivet-like button on the bottom of the switch body pull the knob completely out. Then unscrew the part in the center of the bezel to release the switch. Then remove the plug at the top of the switch. There is a metal box between the switch and the backside of the dash that hold the light bulb and positions the switch that will also come loose.
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#6
My light issues turned out to be a combination of a corroded headlight switch and 4 badly corroded sockets.
Everything works now.

Thanks for the help.

"I drank what?" - Socrates
[+] 1 user Likes jowens1126's post
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