Headlights are really dim

[Tom in SW VA]

Headlights on my 37 Ford are really dim. In fact, they are so dim that I could never drive at night. Is this the nature of the beast or is there a solution or is there something wrong with electrical system? The lights on my Model A Fords are twice as bright. Any help will be appreciated.

PS - The car is totally original with a generator and 6-volt system.

[richard crow]

check all connections & grounds. check gen belt tension. if still dim check charging rate whith lights on poss. gen not charging enought. check batt fluid level.

[dennis33]

Check and make sure your headlights have a good ground.

[G.M.]

The lights will be dim at idle because the generator is disconnected below about 10 MPH. The lights are running on the battery only and there is a voltage drop to the lights. After the car is driven 15 miles to fully charge the battery turn the lights on with the engine running at 30 or 40 MPH speed. The amp meter should show 3 or 4 amps charge. If it is showing a discharge you need to lower the third brush in the generator untill there is a slight charge showing. To much charge rate will boil the the battery if driven a lot in day light. G.M.

[Old Redneck]

Make sure the ground straps are clean. Clean all conections on the headlights.Check the charging rate on the generator as GM sais.

[flatheadfan]

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Tom-

Like others have said, make sure you have good grounds under each light shell and all wiring is viable.

A second problem area that is often overlooked is the lighting disk inside the wire hardness bulb at the bottom of your steering column. The brass terminals do wear overtime and the brass switch contact becomes poorer and poorer. If the terminal stops are not gouged a quick polishing with some 1000 grade paper can rejuvenate things.

A leaking steering box can also reduce the effectiveness of the brass contact switch inside the bulb. The "inners" should be dry when you pull things apart. Obviously, you can clean things up but the problem will only return until the gear box leakage is addressed.

Finally, if all things are operating correctly and you want to enhance your lights there are several things that can be done. If you want to keep a degree of originality, you might want to look into the vacuum metalized aluminum coated reflectors such as Olivra (sp?). These reflectors are made with the same process used to make surgical lights found in hospitals. That is what I am using on my '35. They are somewhat "pricey" but they nearly duplicate the effectiveness of sealed beams and do not tarnish like the silver-coated originals.

Hope this helps.

Tom

[fordscript]

Tom, some great advice, well covered, but on my 37 I soldered a wire to the bulb holder and took it direct to ground on the frame. there are a lot of places between the bulb and ground that can cause a bad ground connection....especially on a 'restored/rebuilt' car that has had everything well painted.

[larry/Texas]

Tom:

There is a discussion on grounding on the Early Ford V-8 Club "Forumn" (www.earlyfordv8.org) titled "Ground Strap Getting Hot" Use the "ground strap getting hot" as the subject line. In the 5th post down from Henryat1140 he makes reference to an article he wrote which includes sketches. This might be of help. Also make sure you have 6 volt cables and not 12 volt cables.

Larry/Texas

[Flathead Fever]

Electrical problems seem to be one of the major problems confronting the home restorer and there should be no reason for this. I cannot overemphasize the importance of buying a voltmeter to diagnose your electrical problems. Voltage meters are simple to use and will eliminate the guessing game. If cars are your passion and you are the type of guy that likes solving problems then please buy a voltmeter. Make sure that it has a minimum of 10 mega ohms of impedance so you can also you use it on modern cars without damaging the very low voltage circuits in the computers.

For some reason electricity freaks people out, I guess its because they can’t physically see electricity flowing through the wires of their cars, so lets just forget about electricity for a moment and pretend we are working on an irrigation system instead of an electrical system because they are virtually the same.

If you had a water tank on the hill above your house and you turned your hose on at the house and hardly any water came out, lets say 20psi, the first thing you would probably do is go see if the tank was full and if you had good pressure coming out of the tank. If the tank was full and the pressure was good, lets say a 100psi, you would conclude that there is a broken or blocked pipe somewhere between the house and the tank. You could have one big leak or blockage or a bunch of little ones. Lets just say it’s a bunch of little leaks. If you had several leaks in the pipe and you were able to measure the pressure losses at each leak, together all the pressure losses would add up to your missing 80psi. The same thing can happen in your lighting system, several small drops in your voltage can cause low amperage flow at the lights. Since your only dealing with 6 volts just a few minor drops will make a big difference. So how do you find all those little voltage drops, you perform what is called a Voltage Drop Test.

A voltage drop test is easier to perform than a water pressure test because you do not need to physically tap into the system to take a pressure reading. All you need to do is touch your two voltage meter test leads to the outside of the wires and the meter will tell you if there is a blockage between the two test leads, it’s really that simple. Remember to think of your wiring, switches and connections as pipes carrying water so in order to test the system there needs to be pressure (voltage) in the circuit so you must turn the lights on during the testing.

Why does this test work, it is because electricity will take the path of least resistance, Example: while current is flowing through a wire, if you were to place your positive test lead on one end of the wire and your negative test lead on the other end and there was a restriction (resistance) in the wire between the test leads, some of the electrons would go around the restriction (resistance) by flowing through the meter and the meter would measure this pressure (voltage) loss. If the wire was good there should be less than 1/10 of a volt flowing through the meter because it is easier for the voltage to flow through the wire than it is the meter. If you were to get a reading of 6 volts there is a complete break in the wire and all of the voltage has to flow through the meter to get around the break. A lot of times you will get a reading of a few tenths of a volt registering on the meter, then the wire is either corroded, probably at the crimped on connectors or maybe it has some broken strands hidden inside the insulation. Remember you are only allowed 1/10 of a volt drop across a wire or connection point, maybe 2/10ths across the contacts of a switch.

Start your inspection at the battery. Set your meter to read DC volts and set the meter scale to read the next highest voltage scale above 6 volts. Your not going to fry anything on an old car by probing around with your voltmeter. Start by touching the positive and negative leads to the battery posts (do not touch your leads to the battery cables only the posts) and read the meter. You should have close to 6.3 volts, if you don’t, you need to charge the battery. Now go to the headlight and remove the wires from the light. The reason you are removing the wires instead of probing them while they are still connected is to test for the available voltage. If they were still hooked to the light you would be performing a voltage drop test across the light bulb instead of checking for available voltage. Hook up your leads to the low beam wire and the ground wire and turn on the lights. If you get a negative reading on the meter just reverse the leads, you can’t hurt anything. You should have close to battery voltage, but lets say you only have 4.6 volts, your missing 1.7 volts. Just like the water pipe this could be one large loss or ten little ones. Connect your wires back to the headlight and go back to the battery.

First, your going to do a voltage drop test between the battery posts and the battery cables ends. Turn the lights on and touch the positive test lead to the center of the positive post and the negative lead to the positive cable end. Lets say the meter reads .2 or 2/10ths of a volt. You have a bad connection at the post, you need to clean it and check it again, the meter should now read zero. Do the same thing to the negative post and cable and lets say you get a reading of .1 volt. You have found 3/10ths or your missing 1.7 volts. Now lets move on to the battery cables themselves, touch the positive lead of the meter to the battery end of the positive cable and the negative lead to the other end of the cable, turn on the lights and it reads 3/10ths of a volt, the cable is bad. Before you disconnect the cable place the positive lead on the crimped end of the cable at the block and the negative lead to the block itself, lets say it reads 2/10ths of a volt. You have a bad connection at the block, you need to clean the block and install one of those star type washers that bites into the block and the cable (always use these style washers on any ground connection). Now you have found 8/10ths of your missing voltage but 9/10ths is still missing. If your vehicle is still a negative ground system attach your negative lead to the wire on the back of the headlight switch that comes from the battery and your positive test lead to the wire going to the lights, turn on the headlights and your voltage meter reads .6 or 6/10ths of a volt. The contacts in your switch are bad. Now your still missing 3/10ths of a volt. Somewhere between the switch and the ground at the headlight is your missing voltage The most likely spot is a rusty ground connection at the headlight. You hook one lead to the ground terminal and the other to a clean spot on the sheet metal and you find the missing 3/10ths of a volt. You need to check every wire, connection and switch in the circuit. The voltage drop test is the fastest and most economical way to find resistance in an electrical circuit.

Something else to consider, older headlights get dimmer with age.

　
Jerry

[jerry grayson]

Good instructions!! I don't know why electrical systems in our old cars scare people so much, I suppose that it is because electricity is smoke!! HE HE Grin.

[jbrittonjr]

Very good instructions!

[flatheadernie]

SUPER job keeping it at a level we can deal with, thanks. ps I drove the 46 coupe last nite and my lights are brighter than my 98 dodge pu , sigh now I have to find out why oh well. LOL ernie n tx

[38 coupe]

I finally did something to improve the lights on my 37 after realizing that my friend's 23 T had brighter headlights. The reflectors on my car were badly tarnished. Bob Drake (and maybe others?) now sells new reflectors that are aluminum coated and vacuum sealed, same as the UVIRA process. These helped a lot. The other change was replacing the headlight lenses. Mine had darkened. I did not notice this until I compared them with new reproduction lenses. I highly recommend both new lenses and reflectors. If you really want to get bright (and spend more money), you can also add halogen bulbs intended for use with generator equipped cars. Order 170-756H which is rated at 35/35W or 170-957H which is rated at 50/35W from Little British Car Co.

Please note that the picture of my car in my avatar was taken before upgrading the headlights and with only the parking lights on. The lights now glow white instead of brownish yellow.

[Tom in SW VA]

Thank you, Jerry! This is wonderful advice!!

Tom

[Tom in SW VA]

Originally Posted by 38 coupe

I finally did something to improve the lights on my 37 after realizing that my friend's 23 T had brighter headlights. The reflectors on my car were badly tarnished. Bob Drake (and maybe others?) now sells new reflectors that are aluminum coated and vacuum sealed, same as the UVIRA process. These helped a lot. The other change was replacing the headlight lenses. Mine had darkened. I did not notice this until I compared them with new reproduction lenses. I highly recommend both new lenses and reflectors. If you really want to get bright (and spend more money), you can also add halogen bulbs intended for use with generator equipped cars. Order 170-756H which is rated at 35/35W or 170-957H which is rated at 50/35W from Little British Car Co.

Please note that the picture of my car in my avatar was taken before upgrading the headlights and with only the parking lights on. The lights now glow white instead of brownish yellow.

This is great advice........ I will try. Can you use halogen bulbs with 6-volt system?? Tom in SW VA

[Fe26]

Originally Posted by Tom in SW VA

This is great advice........ I will try. Can you use halogen bulbs with 6-volt system?? Tom in SW VA

Yes you can, I installed 6volt halogens in my '38' coupe and they made quite an improvement.
The trouble I have now is finding out if I still have a '38' coupe. It is garaged (ricketty old wooden thing) in Christchurch, New Zealand. Our house is near the city centre, the house is kinda OK and our family is uninjured, I never thought to ask how the car and garage were. Wife and I are in Sydney and can't get back.

[FlatheadTed]

A lot of V8s had there bulbs replaced with 30 watt ones ,go to the model A suppliers and get 50 watt ones you will be surprised .

[1931 flamingo]

Unless you've got the correct voltage at the headlight bulb connection, it's not going to make any difference what type/wattage bulb you have there. JMO
Paul in CT

[hbleadsled]

Flathear Fever- Thanks for the detail info. easy to understand and follow I am printing out your post. Harold central coast Ca.

[hbleadsled]

Fe26- I hope everything ok for you in Christchurch, New Zealand, good luck to you and all other'swho live there. Harold central coast Ca.