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9/28/2022 6:59 AM  #1


Headlights blinking On and Off

1966 Mustang Coupe, 5.0 HO Swap, EFI, Painless wiring harness.

Odd occurrence when driving the whip on Sunday evening...  The damn headlights were blinking on and off.  Must have looked crazy on the highway.  Seems to only happen when the car is running.  What's the most efficient way of trouble shooting this with out dissecting the entire wiring harness?  Seems like a bad ground would be a likely culprit but rest of the electronics seem to work fine.

 

 

9/28/2022 7:53 AM  #2


Re: Headlights blinking On and Off

Head light switch has an internal breaker, they get weak with age, put the H/L head lights on relays as an upgrade.


Good work ain't cheap, Cheap work ain't good!   Simple Man
 

9/28/2022 9:54 AM  #3


Re: Headlights blinking On and Off

Headlight current runs through the DIMMER SWITCH. Pull carpet back and check for age-ing.

 

9/28/2022 10:35 AM  #4


Re: Headlights blinking On and Off

If both headlights are blinking at the same time, I’d suspect the headlight switch, or dimmer switch.  Check the wiring plug connectors before replaced the switch.  Could be a problem with the ‘dirty’ connection, clean connections with a contact cleaner.  Best to use “DeoxIT”, to deoxidize to contact points (available on Amazon).  I’ve used this on several connections with good results.
You can also use an eraser (like on a pencil) to clean male stabs of connectors.

 


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

10/02/2022 9:02 PM  #5


Re: Headlights blinking On and Off

Rudi wrote:

Head light switch has an internal breaker, they get weak with age, put the H/L head lights on relays as an upgrade.

 
A handful of $5 relays solves a lot of headlight problems. You can get by with 2 relays if they have two circuits, but I really enjoy my bright lights now.


1963 Ranchero Deluxe, original 260 V-8, modified, AOD, 4 X Disc Brakes, Power Steering and more.
 

10/03/2022 11:47 AM  #6


Re: Headlights blinking On and Off

The headlight switch has a breaker that resets itself thus causing the blinking. Does it do this on both high and low beam. Is the breaker getting weak, try unplugging the headlights. If it still clicks (blinks) I'd say you have a short. (May need a test light to plug into the headlights to see if you can't hear the light switch click) If a short is suspected first guess is the High/Low beam switch. It's already mounted to ground. You could also unplug at the beam switch and do the previous test.


If this forum can't fix it, it isn't broke.
 

10/04/2022 3:54 PM  #7


Re: Headlights blinking On and Off

As everyone has indicated there isn't much to the headlight circuit, just the breaker and switch in the light switch, the dimmer switch and the headlights. This is a schematic for a 66. It sounds like the breaker is tripping and auto-resetting. There is usually an insulator between the dimmer and the floor board- a good place to check, or you may have a short somewhere from the wires to chassis.
EDIT, can't get the picture here, sorry

Last edited by Mach1Driver (10/04/2022 3:56 PM)

 

10/04/2022 5:05 PM  #8


Re: Headlights blinking On and Off

If you are running modern headlight bulbs you need to install relays for the headlights,  They draw too much amperage and trip the breaker in the headlight switch.  I had the same issue.  Went to relays and never looked back. 

 

10/19/2022 4:39 PM  #9


Re: Headlights blinking On and Off

TKOPerformance wrote:

If you are running modern headlight bulbs you need to install relays for the headlights,  They draw too much amperage and trip the breaker in the headlight switch.  I had the same issue.  Went to relays and never looked back. 

You have a P/N for a specific relay kit?  Save me a copy to Painless.

     Thread Starter
 

10/19/2022 6:07 PM  #10


Re: Headlights blinking On and Off

Someone might have a P/N for a "Kit", but for the cost of your email address I'll send you a quickie diagram so you can buy some parts and build your own, if you are so inclined.
BB1
 


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

Board footera


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