After replacing 2 burned out headlight switches (due to wire crushed under a grill mount), installing new headlight harnesses, and cleaning a lot of what looked like spider and mouse debris/crap from my headlight buckets and installing new parking light assemblies, I installed a 30 amp circuit breaker to protect the headlight switch and wiring. I thought everything was ok until 4 nights ago when suddenly my highbeams started flashing on/off. I kicked the low beams on and got the truck home. I left the lights on while checking things out and suddenly the lowbeams started flashing too, on/off at random. I remembered an article that was directed to me, by Alan Horvath, in reply to an earlier post I had(search ..'58 Apache headlight problem) To make a long story short, I completed a relay installation today to operate the headlights and the results are ...WOW !! Not only don't the light flutter now but they are much brighter. MUCH brighter.
I took power directly from the alternator (10 gauge wire) to a second 30 amp breaker and then to the relays to operate high and low beams. All the headlight switch does is energize the relay then all current comes from the alternator through the 10 gauge wiring and nothing at all through the headlight switch. I had checked voltage at the high beam lights before the install and had 12.47 volts, after the install...14.33 volts !!! and no operating problems. The headlight switch is cool to touch and the first 30 amp breaker (protecting the switch) is stable. I suggest this modification to anyone. Whether you are having problems or not the increase in voltage resulting in superior lighting is reason enough to make the install. Took me about 2 hrs and cost less than $34.00. I am thinking about doing the same thing with my tailights....and then who knows.
the 'flashing' headlights woulda been the bimetal circuit in the light switch opening/closing from excess current draw [or cheapy repro switch?] .... let us know how long the bulbs last running at 14V
Great post. I did that several years ago on my 70. Has worked great ever since. I use halagen bulbs.
Bill, you are correct. The switch would have burned out if not for the earlier circuit breaker install. The switch bimetal strip (on the headlight side) was getting hot and opening/closing. It was very hot to touch. Now the switch is cool as it does nothing once the lights come on. Well nothing to run the headlights, it still runs the taillights and dash lights. The bulbs..?? Dont know how long they will last...and doesnt really matter as I can now upgrade the bulbs to halogen if they fry. The main thing is I now have reliable lights and a safeguarded switching system and protected under dash wires. BTW, the switch is a Delco-Remy, made in USA...not a foreign chepo.
I'm so happy to hear about your great results, Bro!
Hey Bill -- 14 volts is what we all *should* be seeing when ever we are getting full power to components; a 12-volt battery is suppose to produce 14 volts.
actually a 12v battery should/can only produce 12v ... the alternator produces 14v [or so] to keep the battery charged while running the components, and if the system is #1, the headlights should be getting as much power as they were designed for, and producing the full candlepower rated for stated longevity
my comment above relates to the fact that some here have said using an 8v battery on a 6v system resulted in shortened bulb life ... seems it might be the same with 14v on a 12v system, would be curious to hear if that's the case
I've been driving old trucks as designed for decades, and never had a lite switch fry, and if I had it happen repeatedly, I'd sure wanna find out why!
Thanks for the clarification, Bill.
Everything on the trucks run on 14 volts. That is the voltage they are designed for. The reason 8 volts will burn out bulbs & acessories is that 6 volt trucks run on 7-7.5 volts & 8 volt battery would have to be set on aprox. 9 volts to charge. If you have 14 volts at the alt. you will have 14 volts at the tail lights.
then the question becomes, if Carl's headlights are brighter now at a measured 14v, why were they dimmer before?
My answer to that, Bill, would be that, before hand, they probably were getting less than 11 volts ... tired wires, poor connections, long wire runs that lose voltage because of distance, etc., etc.
I ran an 8-gauge wire from my battery's +-terminal to terminal blocks on my firewall and powered my fuse box, headlights and electric fan directly from that source -- and my alternator reads that source (instead of the usual BAT connection), too.
That, along with the use of relays, makes a very big difference. The truck runs better, too! See Here
There is alot I dont know or never will about electicity, how is works and why, but I can attest to what I see and what I read on a voltmeter and the lights are now brighter and now operating on approx. 1.5 volts more than before the relay installation. I used the alternator as my bus because it is very close to the headlights and gave me the shortest wire run possible with no voltage loss. Breaker and relays are mounted on the inner fender close to the horn, again very short wire run to the headlights. Short heavy wires means less voltage loss. Alan said probably old wires, less than perfect connections, and long (maybe undersized..??) wire runs caused the early lower voltage reading (before relay install). I agree completely with his diagnosis and thank him for sending me the website with the install information. Thanks Alan
I'm more than happy to have been a help, Brother!
Carl - Can you send me details as to how you hooked the wiring harness head light points into the relays? I am lost after the point of running the 10ga wire to the breaker then to the relays. I can do this with no problem. Not sure how to connect the harness portion to the relay(s. At what point do I make the connection and to what contact on a specific relay?
The system sounds simple and working great, have 2 trucks that need it due to flickering high beams.
After a considerable time off of working on the truck, I am back on it now. I just found and connected a hi tone horn. This is much better than a single low tone horn. Found some spectacular headlights, components and schematic thru Daniel Stern Lighting. Looking forward to being able to see at night. I will post pictures of before and after when finished.
"Nothing new under the sun", as an Old Testament prophet once said. Back in the 1940's and 50's using a headlight relay on 6V lights made the lights bright enough that oncoming drivers would flash their lights, thinking the relay equipped car was running high beams. It's all a matter of reducing voltage drop every time current flows through another switch, conductor, or connector.
Its a worthwhile project for certain. I did it and it was a tremendous help in seeing at night (I also moved up to H-4 Halogens).
So take a look at the factory wiring diagram and find where the hi and lo wires for the headlight switch run in the engine compartment along the inner fenderwell. Then look to see where the wires bifurcate to feed the left and right bulbs (usually pretty close to the radiator saddle and voltage regulator.) Unwrap the wires and find the split, cut the wires here. Install two 30 amp 4 pin relays (if you have room, above the voltage regulator horn relay on the back side of the radiator saddle), preferably water proof. One relay is for the low beam and the other is for the high beam. Sort out which wire is for high beam and low beam.
Then run the low beam wire that is from the headlight switch to the No. 86 pin on one relay and the high beam wire to the No. 86 pin on the other relay. You may have to extend the wires slightly to reach the relays.
Run a ground wire to each of the No. 85 pins. Then run two 12 gauge hot wires from the battery, with water proof 20 amp inline fuses, to each of the No. 30 pins.
Finally, connect each of the high and low beam wires that go to the bulbs to the No. 87 pins (both high beam wires to one relay and the other low beam wires to the other relay). Want to do it even better, run new larger 14 gauge wires to the bulbs.
Once its all wired up, test it. The headlight switch will now trigger the relays, and the relays will feed the bulbs a full 12 volts and a much brighter headlight (no parasitic loss through the headlight and high beam switch, and small stock headlight wires). If it works like is should, tape it all up like factory and you are all set. Its a really great conversion and one that makes driving these old trucks at night much safer for both driver and others on the road.
Go to Summit and get some LED bulbs.... that reminds me I need to do that!