Hi Craig, sorry for not responding to your problem but have been in New Zealand for several weeks and then to our national V8 meet in Echuca for a week. I got your PM. I would be replacing your headlight bulbs or sealed beams one at a time to see if that resolves the issue. I have struck it where conductors or filaments inside the bulb itself are touching together sometimes intermittently and feeding back into the other beams circuit, maybe with road vibration adding to the equation. I doubt water would cause a shorting effect between circuits on a 6 or 12 volt system. Just do one thing at a time so you know what has fixed it. Regards, Kevin.
High Beams stick on.
- Thread starter Old Henry
- Start date
George/Maine
Well-known member
I think the wires from switch to headlight bucket are touching.
Look at every inch for bad insulation could be under fender or along inner fender maybe under a fastener.
Look at every inch for bad insulation could be under fender or along inner fender maybe under a fastener.
Old Henry
Well-known member
Yes. I just replaced a bulb that was dim thinking it was because of age but was still dim after replacement. I felt along the circuit and found a fairly new butt connector warm. I cut it out, twisted the bare wires together, and secured them with a wire nut. The bulb was finally bright after being dim for so long. That was yesterday before we left on our trip.
Old Henry
Well-known member
I did that very thing today when we got home from our trip. I unwrapped all of the light wiring from the engine compartment, where they are all joined to the main wiring harness with old butt connectors, to the bulb wiring. Sure enough, I found lots of rotten and powdered cloth insulation and more than one place where current could have leaked through to a neighboring wire. The dual filament problem stopped while I was unwrapping and separating the wires, obviously part of the problem if not the main problem. I cut out all of the butt connectors and soldered the wires together then separated all of the wires and insulated all of them before re-wrapping them.
We have rain forecast every day this next week here so I'll be putting on some miles out on the wet roads to see if I've got it fixed yet.
Thanks again for everyone's help.
Last edited:
Old Henry
Well-known member
The saga continues.
After all I've done so far I still had a short between the high and low beams after driving in the rain for a while. So, I first disconnected the high beam circuit where the vehicle wire connects to the right headlight pigtail while it was still wet to see if the short was in that pigtail. It wasn't. Then, after everything was dried out, I watered down that area in front of the right tire. No short. I then watered down in front of the left tire. The short occurred. I felt the wiring and connections where the vehicle wire connected to the left headlight pigtail. (Good old Koates trick.) The low beam circuit was hot indicating that it was powering both circuits through there. I cut the connection of that low beam circuit to the headlight pigtail. The low beam of that bulb went off and so did the high beams of both bulbs that were being powered by it. So, the short is in the pigtail of that left headlight. I'll order new pigtails for both lights and cross my fingers.
After all I've done so far I still had a short between the high and low beams after driving in the rain for a while. So, I first disconnected the high beam circuit where the vehicle wire connects to the right headlight pigtail while it was still wet to see if the short was in that pigtail. It wasn't. Then, after everything was dried out, I watered down that area in front of the right tire. No short. I then watered down in front of the left tire. The short occurred. I felt the wiring and connections where the vehicle wire connected to the left headlight pigtail. (Good old Koates trick.) The low beam circuit was hot indicating that it was powering both circuits through there. I cut the connection of that low beam circuit to the headlight pigtail. The low beam of that bulb went off and so did the high beams of both bulbs that were being powered by it. So, the short is in the pigtail of that left headlight. I'll order new pigtails for both lights and cross my fingers.
Old Henry
Well-known member
Some things just can't be fixed and must be replaced. But, I give my full effort to fixing before biting the bullet and replacing.
This is the inside of my left headlight bucket showing the pigtail wiring coming into the bucket with insulation worn out and gone. Could be the location of the short or could be further into the pigtail. Because of the near impossibility of fixing this I'm just replacing both headlight pigtail assemblies.
In all of my investigation and finding this is the first possible location of a short that could really be triggered by water. Hopefully, this will be my last and final repair.
This is the inside of my left headlight bucket showing the pigtail wiring coming into the bucket with insulation worn out and gone. Could be the location of the short or could be further into the pigtail. Because of the near impossibility of fixing this I'm just replacing both headlight pigtail assemblies.
In all of my investigation and finding this is the first possible location of a short that could really be triggered by water. Hopefully, this will be my last and final repair.
Last edited:
Old Henry
Well-known member
I don't know Henry, you may have to bit the bullet on this one and buy some new harness pieces!If the rest of the harness is anything like that part, I'm thinking a new harness would be a good investment.
You may be right. It's not the cost of a new harness that's holding me back. It's the labor to remove the old one and install a new one. I have a real hard time working under the dash where most of that harness would have to be changed over. That, along with just preserving anything original as long as I can, is still holding me back. Friction tape is still way easier than all of that. But, when it no longer is sufficient, I will bite the bullet.
Steves46
Well-known member
Craig, unless you already examined it, the under dash wire harness may be in pretty good shape for it's not normally exposed to the elements unlike your lighting and generator harnesses. Those are fairly easy to change out-especially if one of your kids or grandkids lend you hand routing the replacement wire. 
TJ
Well-known member
Above is my original recommendation. A wiring fire due to a short could cost you a lot more than a new harness. Replace ALL THE WIRING. The under dash harness is 70 years old. Once you start to move it around the insulation inside the cloth starts to break. It is very brittle by now. In addition the old wires have become corroded and cause a lot of resistance. If you want a nice harness that is reasonable in price contact Sacramento Vintage Ford. I've used their harnesses and they are of very good quality.
paul2748
Well-known member
The trick to working under the dash is to remove the front seat. Then you can lie down with lots of room and no twisting and turning to get at things.
JSeery is right. 68 year old wiring, cloth at that. For all that you use your car and under some of the conditions you use it, the current wiring is a problem waiting to happen
JSeery is right. 68 year old wiring, cloth at that. For all that you use your car and under some of the conditions you use it, the current wiring is a problem waiting to happen
51 MERC-CT
Well-known member
When I replaced the harness in my car, I also could not visualize myself trying to get at stuff under the dash.
What I did was disconnect what ever was necessary to loosen the dash and move it away from the firewall. That gave me easy access to everything from above (and mostly in a seated comfortable position)
Don't know if it will work in your situation but it may be an option.
What I did was disconnect what ever was necessary to loosen the dash and move it away from the firewall. That gave me easy access to everything from above (and mostly in a seated comfortable position)
Don't know if it will work in your situation but it may be an option.
Old Henry
Well-known member
Drove 30 minutes in the rain today with no shorts. (I never wear shorts driving anyway. 
)
I took the special non-conductive gum that I chew - Double Mintsulated Gum - out of my mouth and shoved it in between the two bare wires coming into the headlight bucket and molded it around to hold in place. (Had to say that for all who abhor "farmer hacks".)
I actually taped the two bare wires to keep them from touching just to see if I had finally found the real true water activated short. It worked. So, I hope that was it and look forward to putting in the new headlight pigtails when I receive them.
I'm still seriously considering a major wiring harness transplant so keep the encouraging words and installation tips coming.
)I took the special non-conductive gum that I chew - Double Mintsulated Gum - out of my mouth and shoved it in between the two bare wires coming into the headlight bucket and molded it around to hold in place. (Had to say that for all who abhor "farmer hacks".)
I actually taped the two bare wires to keep them from touching just to see if I had finally found the real true water activated short. It worked. So, I hope that was it and look forward to putting in the new headlight pigtails when I receive them.
I'm still seriously considering a major wiring harness transplant so keep the encouraging words and installation tips coming.
Last edited:
Old Henry
Well-known member
I got the headlight pigtails in and, of course, they were authentically cloth wrapped. I didn't like the idea of those cloth wrapped wires going through the fender area where they would be blasted by water, ice, mud, gravel, etc. etc. So, I got some 1/2" double wall heat shrink and covered them. Is that OK?
Picture shows original cloth wrapped, shrink wrap, and one wire covered.
Picture shows original cloth wrapped, shrink wrap, and one wire covered.
Is that like asking permission after doing the deed.