Wire from light-switch to dimmer?

[scumdog]

OK, before I rip apart stuff I don't really need to (I'm good at that!) can somebody tell me if the wire that feeds power to the dimmer switch from the light switch runs inside the car or does it pass through the fire-wall and run down the outside of the car to the dimmer switch?

i.e. can I access this wire from inside the car or do I need to jack the car up and work from underneath it? (Not really good fun, it's mid-winter here).

I plan on using that power feed wire from the light switch to activate a relay which in turn will feed power to the dimmer and then onto the headlights, that way I won't have the issue of the head lights going out at random due to the overload on the light-switch activating and cutting out the power to the headlights.

[simplyconnected]

Sometimes I have to pinch myself for being thick. I read about the dimmer, and immediately thought of all those little dashboard lights.

Oh... High and Low Beams! A-ha!

The wire goes straight from the headlight switch to the floor switch, and then through the firewall to the headlamps. Many wires run along the floor inside our cars.

I don't know the full extent of your thoughts, but here's my suggestion:
Since the high and low beam wires are controlled by conventional switches and those wires go to the front of your car, why not use them to turn on two separate relay coils?

Connect a #16 wire to your battery + with a 10-amp fuse close to the battery, and feed both relay contacts with this power. The wires from your dash will control each relay coil. So as a relay energizes, the contact closes passing battery power to your headlights.

This will lighten a large load on the wire that feeds your dash, the headlight switch, foot switch, AND you may use today's high powered headlight lamps with no danger of overload.

It never made sense (to me) to send heavy power from the battery, to inside the dash, just to return it to the front of the car for headlights. They don't do that with horn power.

[scumdog]

Thanks Dave, I 've a fancy relay to do just what you've suggested BUT I thought by using one relay near the dimmer switch (what we call the dip-switch here in NZ!) I would not have to mess with the rest of the wiring.

My idea was a power lead from the battery to the relay near the dimmer and the then power from there to High and Low beam.

So in effect the light switch is merely to activate the relay to provide the power feed to the dimmer.

Reason:

It means just one wire from battery-to-relay-to-dimmer (Where the original wire from the headlight switch went on to) and splicing the relay into the original wire that goes from the light-switch to the dimmer-switch

[Jimz Bird]

Just to tag onto what Dave said.

You are probably familiar with:

http://www.madelectrical.com/electricaltech/brighter-headlights.shtml

A main point is to keep the "voltage drop" from excessive wiring to a minimum. That would be - as Dave said - by keeping the relays at the front close to the headlights, ESPECIALLY if you are upgrading the headlamps to modern ones.

Also best to switch to a three wired alternator.

Same site and he talks of using the Delco but I am going to opt for the Ford (3G) alternator. Again, agree with Dave in his info when writing up about alternators that I would rather stay Ford..

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

One last thought which ties in I think are the reasons for the 3-wire:
1. Allows full function or the "GEN" light;
2. Provides better voltage "sensing"

http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

HTH and doesn't confuse the main issue of Headlight Relays.

[redstangbob]

I'd like to add a note that is flairbird specific. Scumdog has a 66 townie I believe, but for each year of the flairbird changes were made to the wiring. Guys with 64's should know there was a problem with harness failures/fires, the exact cause escapes me right now. 64 & 65 cars have virtually all electrical current going through the AMP gauge, take a gauge wire off and you have no power to anything. 66 AMP gauges were shunted, they usually don't deflect like older cars will. If you plan on going with a higher output alternator (I'm a fan of the 3G), remember if you're pulling more power for amps or stereo's ect, all that current will travel through a bullet connector in the firewall. A discreetly run wire to the battery side of the starter solenoid will help avoid overloading 45 year old wires, and maybe a fire. With some owners being original is the most important thing, take the time to look your harness over, I bet you find cracked insulation or almost always a previous repair that was done badly. JMO Bob C

[simplyconnected]

Good article, Jim. I agree with it. This is a perfect opportunity for Scumdog to use the VOM I sent him.

...64 & 65 cars have virtually all electrical current going through the AMP gauge, take a gauge wire off and you have no power to anything...

No, if Scumdog takes his power off the battery + per my instructions, it should work just fine. We are taking a major load OFF the headlight switch without altering the meter shunt.

...If you plan on going with a higher output alternator (I'm a fan of the 3G), remember if you're pulling more power for amps or stereo's ect, all that current will travel through a bullet connector in the firewall. A discreetly run wire to the battery side of the starter solenoid will help avoid overloading 45 year old wires, and maybe a fire...

Again, you are forgetting that all-important FUSE. Protect your wires with proper size fuses. If you wire with 14-ga. stranded copper wire, use a 15-amp fuse. #12 wire gets a 20-amp and #10-AmericanWireGauge gets a 30-amp fuse.

I used to be a big fan of the 3G, but Ford now offers much better, on all new cars. They output over 100-amps, (when you need it).

Whatever alternator you choose, make SURE you use an inline fuse on the feed wire. This is different from folks who use generators.

I can't stress this enough: Internal alternator diodes can short to case, draining as much battery power as possible in the shortest amount of time. If you don't have a fuse, then the alternator wire becomes the fuse. For under $4, CLICK HERE for an excellent fuse. If you look deeper at Del City, you will find the holder for this fuse.

JohnG recently installed a GM 3-wire alt. They work exactly the same as Ford's 3-wire, with a GEN light wire, which is really a 'sense' wire- to tell the alternator that the key is switched on. His new alt works the way you would expect it should. So, our choices in alternators is really vast. I prefer the Ford alternators because that's what I have.

As far as this thread goes, I go back to this question: 'What do the OEM's use in new cars?' Jim's article mirrors the answer.

[scumdog]

Somebody replaced the alternator & regulator in my '66 before I got it, I'll wait until theres enough light for me to see what type it is.

But regardless, it has given me no grief, the battery is into it's 6th year with no problems there.

And my car has no A/C or other power-draining gizmos so I have no need to upgrade my charging system.

I was just wanting comment on the two options of how to run my headlights from a relay system, one way needs only one relay and a minimum of disruption to the factory wiring

The other (seemingly the more popular one) means a shorter link from the relays to the headlights but involves more messing around with wires, splicing into the headlight loom, relay mounting etc.

[redstangbob]

HaHaa very good Dave, you managed to pick through and ignore the flairbird particulars. I never suggested adding a circuit without a fuse, I was pointing out the fact that the factory harness has some known flaws. Unless a new wire is brought in to supply additional accessories, everything goes through the Amp gauge and it's wires. And if a new 100 amp alternator is asked to deliver without any modifications, that current will come through the fairly small connector in the factory harness. I just thought flairbird owners might want to know that before they make changes they don't fully understand. I don't know how your Galaxie harness was made, I was speaking of flairbird specific. Please excuse if I misinterpret your reply, it might just be my turn to be a little thick.

[simplyconnected]

Bob, I completely understand about the flaws. Forgive my lack of specifics, but again I assumed the wires feeding the old circuits would get a new fuse with the installation of a new alternator. What size? Always fuse according to the wire size you are using.

When Ford made these circuits originally, the supply met the demand, and wire & fuse sizes were proper. Over time, situations changed. We can always protect ourselves.

The OEM's recognized a bad situation, where long lengths of wires were UNfused, running inside hot engine compartments and through steel holes in the firewall. So they installed 'fusible links', which served as slo-blow fuses. They were rightfully installed under the hood, close to the battery. In a properly running electrical system, you would never know they are there. But with troubles, finding the correct fusible link gave us fits.

Modern cars mount a real fuse box close to the battery, which feeds other fuse boxes in the dash. This is the way to go.

If you install a fuse box close to your battery, it will protect the downstream wire against fire. Some wires carry 30-amps to the headlight switch. Fine. Fuse that existing wire properly. Not enough current to meet the demand? Run another properly fused wire.

I never understood, putting fuse boxes under the dash. They are a real pain to access, and nearly impossible to see the link. My cousin's Amphicar (German) has two fuse terminals; one under the front bonnet, and another in the rear engine compartment. Both are easy to access.

So, Classic Birds, Squarebirds, Bullet, Flair... and ALL cars' electrical systems are improved with the addition of an easily accessible, under-hood, fuse box. Do you really need one? It's like fire insurance or a motorcycle helmet... you never need it until there is a mishap. Then, hope you have the best. - Dave

[simplyconnected]

...means a shorter link from the relays to the headlights but involves more messing around with wires, splicing into the headlight loom, relay mounting etc.

Do you have a supply of crimp-on bullet connectors? There is no need to permanently alter your car's original wiring.

Under the hood, simply unplug the low-beam wire, and plug in your own feed to a relay coil. Do the exact same with the high-beam feed wire. Then plug in both relay's contact wires to the corresponding headlight bullet connectors. The rest of the wiring connects to chassis (GND) and a fuse from Bat +.

You don't need to fish under your carpet or cut wires under your dash. This is the easiest and most efficient way to upgrade your headlights. But hey, it's your car. Do whatever you like. - Dave

[stubbie]

Light Switch

I was just reading your posts about the 64 electricals and all the power to the dash going through the amp meter. I have just recently pulled the dash facia and replaced all the globes and cleaned up all the contacts on the gauges etc. After replacing I found that the light switch when on is now overheating. Could this be caused by a power source coming into contact with earth or has my light switch suddenly become defective?

[simplyconnected]

I need more info, stubbie. How hot does it get? How long does it take to heat up? Did you replace with different number or brighter bulbs? This draws more current. Did you add more bulbs (usually comes when adding Stewart-Warner type gauges)? This also draws more current.

I cannot rule out the possibility that one of your dash light feeds has shorted. But, you can go around the dash and look. I suppose if you left a bulb out but mounted the socket, the center wire could ground inside the light socket.

Your light switch dimmer is made of NiChrome (resistance) wire and it is designed to run a little hot. That's why the coils are surrounded with porcelain. - Dave

[redstangbob]

Getting the instrument panel in and out of a flairbird is like wrestling an alligator. I've found it faster and easier to take the steering wheel off and tape up the column so it doesn't get all scratched up. If you fought with it at all you could have easily pinched a wire. Try dimming the panel lamps all the way down then check how hot the switch is, this will tell you if the problem is in the dash lights or under the hood. Double check the wires in the clock housing first, they can be a bugger too. Also remember the light switch has a lamp (and wire) as well as the key switch. Good luck, Bob C

[stubbie]

Light Switch

Hi Dave
I noticed the switch getting hot because I could smell the wires burning. It was quite hot to touch and it only took 20-30 seconds. The bulbs were different numbers but they were slightly higher in wattage. I havn't got the globes in front of me but I think they were 5.2 watt instead of 4 watt. No I only used the same number of bulbs. Bob I did wrestle with the alligator I had to pull it halfway out a second time as I couldn't get one of the lower panels to fit correctly. Didn't realise there is a small metal section 1/4 inch long sticking up on the back of the panel that stops it from going into place if not seated correctly so it is possible I have a pinched wire. the only way to check is to do it all over again. I also just realised that I put new globes into the backup lights, there were no globes in there at all. Maybe this is why? Phil

[redstangbob]

The back-up lights only come into play when you're in reverse, I don't see that as your problem. I'm betting on a pinched wire. When people see a flairbird they almost always comment on how cool the dash is, they don't know what a PITA it is to service one. Good luck, Bob C