Hello,

I have a 1955 F100 that I just got put back together after a complete rebuild. I have 12V wiring and am using a 14 circuit universal wiring harness. My current task is attempting to get the headlights, running lights, turn signals, and brake lights working in the wiring portion. I searched around on the forum a few days ago and located the diagrams provided by Harrier shown at the end of my post. For no reason beyond thinking the relay being involved would be better, I chose to use that diagram. My only difference from the diagram is I am using a turn signal switch with lighted handle sold by Midfifty (7 wire), which I have attached the wiring diagram for. It uses a 3 prong flasher and I am not sure which was used in the diagram I used. I have completed wiring from the diagram exactly the same, at least quadruple checked for accuracy, as the diagram with power for the flasher coming from the ACC, then it has a P and L terminal that are wired into their respective ends on the turn signal switch.

My scenarios:

KEY OFF / HEADLIGHT SWITCH IN PARKING LIGHT POSITION
-All parking lights work properly with exception of drivers side front. This parking light does not light up and the left turn signal indicator on the dash is illuminated solid.

KEY OFF / HEADLIGHT SWITCH MOVED TO LIGHTS ON POSITION
-Front parking lights are not illuminated, rear parking lights are. Headlights are not illuminating but I am showing 12.5-13V at bulb using multimeter by putting red into terminal and black onto the ground for the headlight socket. Dimmer switch works properly, beam indicator on dash works for brights, but still no illumination from the bulbs despite power to them. I have 2 brand new bulbs I just purchased from NAPA yesterday.

KEY ON THERE IS NO CHANGE TO ABOVE SCENARIOS

KEY ON / HEADLIGHT SWITCH PUSHED IN (OFF)
-All four turn signals function properly

KEY ON / HEADLIGHT SWITCH MOVED TO LIGHTS ON POSITION
-Drivers side turn signals work fine, Passenger side glows but very dim and does not flash.

Brake lights work fine in all scenarios. With exception of the headlight bulbs not illuminating despite having power at the terminal, I have verified through the scenarios that all other lights are working at some point. Any assistance would be appreciated, Thank You.

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This is the standard wiring.



This one is with adding a fuse panel and headlight relay.



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I am going to have to look at this in the morning, but for now you need two relays, one for low beam and one for high beam switched from the dimmer switch (beam selector switch).not the headlight switch.

 

You don't say what universal kit you are using.

The first step would be to double check for good grounds on all bulb sockets. If you have power at the headlamps but no illumination, it sounds like poor grounds.

I had the same issue with my headlamps because the grille and buckets were so well painted there was no ground. Rather than grind paint away, I ran an extra ground from the headlight buckets, through the harness, and to a central ground stud.

 

Thanks for the replies so far guys. I will have to add in a second relay tomorrow and fix that issue.

As far as the wiring harness brand I am unsure. I bought it probably 5-6 years ago but most likely it is a generic one, not Painless or name brand like that. I will also check the grounds tomorrow again thank you for the advice. I had not thought of checking the ground because when using the multimeter I was able to get the voltage reading by touching the probes to the terminals themselves. Maybe the ground is good enough for a multimeter but not for the actual light?

 

Effietrucker is correct as it sounds like bad grounds at the headlight socket pigtails and the turn signal/parkling light sockets.

For scenario #1 Double check to see if the left front turn signal/parking lamp bulb is in the socket correctly. Even though the pins are offset, if you try hard enough you can put them in 180 degrees off and you will have really weird electrical problems. I've done it myself. LOL..
If they are installed correctly, it then sounds like a bad or in this case a missing ground. Test out the missing ground theory by pulling the bulb out and see if the left turn indicator goes out. If so, you found that because there are two filaments in the bulb and a bad ground, current flows from one through the other in series and finds a ground thru the left turn indicator bulb, thus ligting it. If you add a temporary ground to the turn signal socket mount and it works, make it permanent.
Scenario #2,
Maybe I am misunderstanding. You pull out the headlight switch all the way out and the parking lamps don't come on? That I believe is normal. They don't on mine anyway. As far as your headlights not illuminating with 12 volts at the sockets. One again, a bad high resistance or missing ground. A digital voltmeter is a device that can "see" a voltage there. But, it does not tell you if there is enough current flow available for the headlights to work. So try adding another temporary ground. Run one from your engine block or even back to your battery terminal ground. If they now work, make it permanent.
Just me, but since your motor mounts may have rubber, and your frame mounts have rubber, then adding a ground strap or a good ground wire between your frame and engine block and your firewall to engine block will help.
I could be wrong about the above, but I hope it is helpful.
PS
I think your relay wiring is correct. SInce the relay is feeding (switching) 12 volts to your dimmer switch you only need that one relay. The dimmer switch is just switching between high or low filaments. So one relay is all you need, just how you wired it.

 

So in that case the dimmer switch would be switching the full output of the relay and the total draw required by the low or high headlights. Is it not better to have the contacts in the dimmer switch just switching the minimum amount to trip the relay direct to the lights? That is what relays are for.

 

Yes sir, you are correct relays are used for switching high current loads. And one could be added for switching between the brights and dims if wanted, but it is not needed in this case. Relays for headlights were not used in the stock wiring. Also since he has rewired a 55, and if he is still using the stock dimmer switch, it was designed to handle about twice the current since it was a 6 volt truck from the factory. So it, the contacts in the dimmer switch, will more be more an adequate for a 12 volt set up.
In the end, if he wants to add a relay for brights/dim being triggered by the dimmer switch it's OK. But I just wanted to point out its not really neccessary.

 

Reporting back today after a few more hours of messing around with the wiring. So today I added grounds as mentioned. I ended up grounding tail lights and parking lights/turn signals by running a wire from the housing to some bare frame metal I sanded down to. I also ran the ground wire for the headlights down to the same frame location. This has corrected all issues with the turn signals and parking lights as mentioned in the scenarios above. I must have not been getting good ground through the painted surfaces as mentioned. Thank you for the assistance with this!

I still have issues with headlights. I can not get them to turn on at all and for the life of me cant figure out why. I plugged the lamps into the socket and nothing happens. I used my multimeter and checked voltage on the terminals coming out of the lamp after they were plugged into the socket. I am reading 12.3-12.7 at the terminals but neither light is working. When I switch the dimmer switch to brights the voltage is the same but has switched to the other terminal as it should but still no actual light. Any thoughts?

Hooler1 - From my scenario #2 above I was under the assumption that if I pulled the headlight switch all the way out that parking lights and headlights would be on at the same time. So the front parking lights are supposed to shut off when the headlights are on?

 

If you have power to both terminals of your headlight sockets and still no illumination, then you either have bad bulbs or bad grounds. If you have it narrowed down this far, you're on the home stretch.

If you're using an original or original-type headlight switch, then the park lights going out when switched to headlights is correct and normal. It wasn't until the late 60's that cars and trucks had marker lamps on with headlamps.

 

So my neighbor is working on another project vehicle and I was talking to him about the issue. He pulled out one of his newer LED style bulbs with the conversion kit integrated into it from his vehicle. Plugged it in to both sockets and lights work fine, so it comes down to the bulbs I guess.

I just purchased both lights from NAPA this week. These are the ones I purchased.. https://www.napaonline.com/en/p/LMPH...pressionRank=1

The NAPA website says they are a guaranteed fit for my vehicle, but now I am wondering if they are for a 6 volt system maybe? I dont see it listed anywhere on the site page but the box does say 6.4V. Has anybody purchased these for their trucks? I will have to get ahold of NAPA tomorrow if not, either way I will be returning them.

 

If you plugged 6v lamps into 12v, you may have popped them instead of them being defective.

 

I searched and found an older thread about this and a response from Earl who unfortunately passed away. You might of seen a thread about him in the threads below. When he saw about the same question on which headlights to use with a 55 F-100 converted to 12 volts he told the O.P. to ask for a pair of 6012 headlamps. He pointed out something really interesting. The 6 volt versions are numbered 6006 and the 12 volt ones are 6012. The part numbers reflect the headlights voltage.
On your pair I am wondering if the headlights filaments got smoked by someone else trying to use the 6 volt versions on a 12 volt system and they returned them and they accidentally got re-stocked. But man they must of been bright when they were working!

 

Just out of curiosity I looked on NAPAs website. If you search for a 6012 bulb it don't come up with one. But it shows an LMP6014 and a H6024N. So they may be newer replacements for the 12 volt 6012.
Let us know what you end up using and if they are working for you.

 

I talked to my local NAPA yesterday. The guy said the 6014 is now the replacement for the 6012. They are not available in the stores so I would have to order them again. I did not order them yet as I am now debating about going to the same look bulb but with the h4 conversion for ease of replacement instead ordering one each time since no local shops carry the 6014.

I did find this info on a Camaro forum through google search...

The 6012 is the original bulb. The 6014 is a replacement bulb for the 6012. The 6024 is a halogen bulb. Here is the results of a test on 6012, 6014 and 6024 headlights. At 14 volts a 6012 bulb draws 2 amps on low beam, a 6014 draws 3 amps and a 6024 draws 1.75 amps. On high beam a 6012 draws 3 amps, a 6014 draws 3.5 amps and a 6024 draws 4 amps. The increase in current draw between the 6012 and the 6024 headlights shouldn't cause problems with a headlight circuit that is in good condition.

 

It's your call, but the H4 headlamp kits are kinda spendy, if you haven't already checked. (They were the last time I did, for good ones, anyway) Personally, I'd opt for a set of the 6024 Halogens, which look perfectly stock, have good lighting that will last a long time at a reasonable cost and go driving. That extra $1-200 can go elsewhere important. I guess it depends on how much night driving, and where, you plan on doing.