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    7/03/2018 11:26 PM  #1

    Vicfonz
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    From: Southern California
    Registered: 3/21/2018
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    headlights headache

    today I went to mess with my headlight and put it back together..now I cant get them to come on..when I pull the headlight switch knob 1/2 way out the parking lights go on as they should...when I pull it all the way out to turn on headlights the parking lights stay on..no headlights come on...everything works..turn signals,brake lights and tail lights,horn,gauges...but no headlights nor high beems for that matter..i did fix the horn a couple days ago..also messed with the headlight switch to get the gauges to light up...im suspecting a bad switch but just wanted to see if any of yall had a problem like this...everything after I fixed (or thought I fixed) before this worked fine sooooo?

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    7/04/2018 4:08 AM  #2

    TKOPerformance
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    Re: headlights headache

    I would start by checking all the grounds.  I think it more likely that a ground was disturbed than that the switch suddenly went bad. 

    I will also say, that if you are running modern headlight bulbs you need to add relays for both the low and high beams.  This is NOT your problem, BUT its something you need to do to prevent the draw imposed by the new bulbs from overloading the headlight wiring and switch and causing the lights to go off while driving at night without warning.  Adding relays is super easy, and they can be concealed if you are concerned about appearance. 

     

    7/04/2018 7:24 AM  #3

    BillyC
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    Re: headlights headache

    Besides checking grounds have you checked connections at the switch and confirmed that you have power on the load side of the switch? You obviously have power to the switch and it is working as far as parking and turn lights. I would check the wire to the headlights where it leaves the switch.

    "anyone that stops learning is old, whether at twenty or eighty"Henry Ford
     

    7/04/2018 11:00 AM  #4

    GPatrick
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    Re: headlights headache

    Check to see if you have power to the high/low beam switch.  If you don't have power there it is likely the main switch.  If you do have power there either you knocked the connector loose or that switch is bad.

     

    7/04/2018 2:52 PM  #5

    wsinsle
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    Re: headlights headache

    Does the front park lights go out when you pull the headlight switch out all the way. I you have standard wiring, the front park lights should go on when pulled half way out but off when all the way out. If they don't go off maybe the switch is not working correctly with the second half pull. I would still take TKO's advice and check grounds if you were messing around the head lights.

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

    7/05/2018 4:52 AM  #6

    John Ha
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    Re: headlights headache

    When something you tinkered with worked before you tinkered and doesn't work after it's pretty certain that something you did during the tinkering is the cause.  Check everything, looking for pinched wires, unattached wires, etc.  It sort of sounds like the connector that goes on your light switch is not on correctly, since the parking lights stay on with the switch fully out.  You didn't say that you removed that connector but it is possible to get it on wrong.

    Founding Member of the Perpetually Bewildered Society
     

    7/05/2018 12:21 PM  #7

    Alessandro
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    Re: headlights headache

    John Ha wrote:

    When something you tinkered with worked before you tinkered and doesn't work after it's pretty certain that something you did during the tinkering is the cause.  Check everything, looking for pinched wires, unattached wires, etc.  It sort of sounds like the connector that goes on your light switch is not on correctly, since the parking lights stay on with the switch fully out.  You didn't say that you removed that connector but it is possible to get it on wrong.

    I like this !

     

    7/05/2018 12:36 PM  #8

    Alessandro
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    Re: headlights headache

    TKOPerformance wrote:

    I would start by checking all the grounds.  I think it more likely that a ground was disturbed than that the switch suddenly went bad. 

    I will also say, that if you are running modern headlight bulbs you need to add relays for both the low and high beams.  This is NOT your problem, BUT its something you need to do to prevent the draw imposed by the new bulbs from overloading the headlight wiring and switch and causing the lights to go off while driving at night without warning. 

    This thing of  having the lights off while driving at nite seams the same thing happen to me .
    Now i have replaced the switch and seems no problem. 
    the modern headlights  you sayd are like Xenon , led,  other super dooper mega light or
    the " TRADITIONAL "   bulb  like    all the car has ( H4) ?
    thanks !

     

    7/05/2018 1:07 PM  #9

    BobE
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    Re: headlights headache

    As pointed out in other posts, the parking lights should go out when the switch is pulled al the way out.  As you indicate, your parking lights stay on ... I'd suspect the switch.  Troubleshoot as stated in other posts.

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

    7/05/2018 2:27 PM  #10

    Vicfonz
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    Re: headlights headache

    after I had fixed the headlight switch I fixed the horn issue...do you think I could have moved a ground somewhere around that area?..i don't think anything is related...the car was rewired with American autowire prior to when I bought it...

    TKOPerformance wrote:

    I would start by checking all the grounds.  I think it more likely that a ground was disturbed than that the switch suddenly went bad. 

    I will also say, that if you are running modern headlight bulbs you need to add relays for both the low and high beams.  This is NOT your problem, BUT its something you need to do to prevent the draw imposed by the new bulbs from overloading the headlight wiring and switch and causing the lights to go off while driving at night without warning.  Adding relays is super easy, and they can be concealed if you are concerned about appearance. 

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
       •Thread Starter
     

    7/05/2018 2:28 PM  #11

    Vicfonz
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    Re: headlights headache

    this will be my next step..as soon as I can get down there

    BillyC wrote:

    Besides checking grounds have you checked connections at the switch and confirmed that you have power on the load side of the switch? You obviously have power to the switch and it is working as far as parking and turn lights. I would check the wire to the headlights where it leaves the switch.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/05/2018 2:29 PM  #12

    Vicfonz
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    Re: headlights headache

    I was thinking the samething..im going to get down under the dash as sson as it cools down lol

    GPatrick wrote:

    Check to see if you have power to the high/low beam switch.  If you don't have power there it is likely the main switch.  If you do have power there either you knocked the connector loose or that switch is bad.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/05/2018 2:31 PM  #13

    Vicfonz
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    Re: headlights headache

    the parking lights go on solid at 1/2 pull and also stay on on a full pull...weird thing is besides them stayig on..the work as they should when I turn on the turn signal etc

    wsinsle wrote:

    Does the front park lights go out when you pull the headlight switch out all the way. I you have standard wiring, the front park lights should go on when pulled half way out but off when all the way out. If they don't go off maybe the switch is not working correctly with the second half pull. I would still take TKO's advice and check grounds if you were messing around the head lights.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/05/2018 2:32 PM  #14

    Vicfonz
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    Re: headlights headache

    this is a good point...I think im going to disconnect and then reconnect

    John Ha wrote:

    When something you tinkered with worked before you tinkered and doesn't work after it's pretty certain that something you did during the tinkering is the cause.  Check everything, looking for pinched wires, unattached wires, etc.  It sort of sounds like the connector that goes on your light switch is not on correctly, since the parking lights stay on with the switch fully out.  You didn't say that you removed that connector but it is possible to get it on wrong.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/05/2018 2:33 PM  #15

    Vicfonz
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    Re: headlights headache

    yes im thinking same...im going to pull the plugs out and reconnect..maybe I crossed a wire somewhere?

    BobE wrote:

    As pointed out in other posts, the parking lights should go out when the switch is pulled al the way out.  As you indicate, your parking lights stay on ... I'd suspect the switch.  Troubleshoot as stated in other posts.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/05/2018 4:38 PM  #16

    Prof
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    Re: headlights headache

    All current flows through the dimmer switch. Make sure it has been replaced recently and the connections are protected in that area. A rubbed wire around the dimmer switch would do exactly what you are describing.

     

    7/06/2018 12:41 AM  #17

    Vicfonz
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    Re: headlights headache

    hmmm interesting...ill check it tomorrow see if I got anything rubbing...it does look new last time I checked

    Prof wrote:

    All current flows through the dimmer switch. Make sure it has been replaced recently and the connections are protected in that area. A rubbed wire around the dimmer switch would do exactly what you are describing.

     

    "If Someone Did it on Youtube...So Can I...Well.....Unless its Heart Surgery,Thats Kinda Hard"
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    7/07/2018 8:53 AM  #18

    John Ha
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    Re: headlights headache

    Vicfonz wrote:

    after I had fixed the headlight switch I fixed the horn issue...do you think I could have moved a ground somewhere around that area?..i don't think anything is related...the car was rewired with American autowire prior to when I bought it...

    The fact that it's not a factory harness throws a wrench into the works.  Some aftermarket harnesses are configured so that the front parking lights stay on when the headlights are on.  I have no idea if yours is like that.
     

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    7/07/2018 9:04 AM  #19

    John Ha
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    Re: headlights headache

    TKOPerformance wrote:

    I will also say, that if you are running modern headlight bulbs you need to add relays for both the low and high beams.  This is NOT your problem, BUT its something you need to do to prevent the draw imposed by the new bulbs from overloading the headlight wiring and switch and causing the lights to go off while driving at night without warning.  

    If the new headlight bulb wattage ratings are the same as the original lamps, relays are not necessary (although adding them will increase their brightness by providing more voltage at the lamp).  The only time you must add relays is when you replace the headlights with units of higher wattage, say 75 W (originals are 55 W low beam, 65 W high beam)

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    7/07/2018 9:49 AM  #20

    TKOPerformance
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    Re: headlights headache

    That's true, but you'll find most replacement bulbs are higher wattage, plus, original wattage bulbs fall into the same category as bias ply tires IMO.  If the car was a 100% restoration then fine, but if you drive the car and value your life its best to upgrade to better bulbs for better visibility at night. 

     

    7/07/2018 6:52 PM  #21

    almcgee
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    Re: headlights headache

    In my experience, adding relays increased the brightness using original equipment bulbs.  The voltage drops from the headlight switch to the headlight bulbs by a lot.  In my case the voltage at the headlights was less than 7 volts before installing the relays.   After installing the relays the voltage at the headlights was 12.5 Volts and the change in brightness was very noticable.

    Mustang Steve Bash in Gruene, Texas September29-30, 2023
     

    7/07/2018 8:02 PM  #22

    wsinsle
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    Re: headlights headache

    John Ha wrote:

    Vicfonz wrote:

    after I had fixed the headlight switch I fixed the horn issue...do you think I could have moved a ground somewhere around that area?..i don't think anything is related...the car was rewired with American autowire prior to when I bought it...

    The fact that it's not a factory harness throws a wrench into the works.  Some aftermarket harnesses are configured so that the front parking lights stay on when the headlights are on.  I have no idea if yours is like that.
     

    The AAW wire kit uses the standard light switch but if someone rewired the car they could easily add a diode to keep the park lights on when head lights are on. The AAW also uses relays but I feel are not as good because the relays are mounted under the dash. That all said I think the AAW kit uses fuses to operate the relays. The standard head lights use a circuit breaker inside the light switch. I have to ask the obvious, did you check fuse after messing with the head lights. 

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

    7/08/2018 5:47 AM  #23

    TKOPerformance
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    Re: headlights headache

    The rheostat design of the original headlight switch inherently creates a lot of resistance in the circuit, so the voltage drop Al experienced is not surprising.  The size of the wiring running to the headlights also doesn't help (too small). 

    Mounting the relays under the dash is frankly a dumb idea.  The relays need to be mounted as close to the headlights as possible, so the path between the relays and the headlights is as short as possible, thus reducing the voltage drop as much as possible.  I simply mounted mine to the LH inner fender.  I have a bank of four relays there now (two headlight, two cooling fan).  If you don't want to see the relays they could be mounted in the inner fender area.  I didn't go that route because I didn't like the idea of the relays being exposed to road conditions.  If you go that route I would advise using a weatherproof housing. 

     

    7/08/2018 9:34 AM  #24

    John Ha
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    Re: headlights headache

    TKOPerformance wrote:

    The rheostat design of the original headlight switch inherently creates a lot of resistance in the circuit, so the voltage drop Al experienced is not surprising.  

    The rheostat is only used for instrument, radio and shifter quadrant illumination.  It's completely independent of the headlight circuit, other than being supplied by the same power source and being in the switch housing.

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    7/08/2018 1:29 PM  #25

    TKOPerformance
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    Re: headlights headache

    By being supplied by the same power source it still acts as resistance in the circuit, whether its directly in the A to B path to the headlight bulbs or not.  The current running through the rheostat hits a bottleneck, against which it has to flow, meaning amp draw increases, and thus amperage available for the other portions of the circuit connected to the same feed is now reduced.  It would only be inconsequential if the rheostat was in line after the headlight bulbs. 

     

     

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