'47 Car Headlights Won't Come On

dwick01

dwick01

Senior Member
Headlights on my '47 will not come on either high beam or low. They have never worked since I got the car. All other lights work as they should. Everything is stock 6 volt. The wiring at the buckets look fine and they are original. Can someone tell me where and how I should start looking first for troubleshooting? Regretfully, I am electronically challenged. Thank you in advance.
 
I would recommend the following checks to begin: 1. Test and confirm headlight bulbs are good. 2. Check the bullet connections from the buckets to main harness. 3. Check the connections for tightness and corrosion at the dimmer switch.;this is where the power source from the headlight switch flows into for your headlights. 4. Take a volt meter and with the headlight switch on, see if you can get a reading from the headlight connection terminal. If you need a diagram, Mac Vanpelt has an excellent website: http://www.vanpeltsales.com/FH_web/flathead_drawings_electrical.htm

Hopefully it will be something simple. Steve
 
Steve's suggestions are good ones.
Often the problems with electrics in old cars ends up being a bad ground. Without a good solid, clean ground connection, nothing will work as it should.

I'd add that checking the grounds with a separate wire and clip leads is worthwhile. If you visualize that one side of the circuit is in the wiring harness and the other side (the return side) is in the sheet metal of the body and chassis, that might help. Rusty connections are the bane of old cars.

I have a box of electrical only tools, and the clip leads are the most valuable tool in it.
 
First get a wiring diagram and look it over so you understand where the power comes from and the route/wires that run your lights. Get a 6/12 volt test light and hook the alligator clip to a GOOD ground. Touch the test light tip to the power input side of the light switch if it lights there is power there. Next turn on the switch and test the output side, if there is power there go to the dimmer switch and check the input and output sides on it. Chances are that one or the other is dirty/bad. If power isn't getting to one or the other look for a broken wire or bad connection. If you have power to the lights look at your grounding.
 
Last edited:
The dimmer switch would be the first place to check if all the other lights work. You may have a bad connection or a bad switch.
 
Exactly, dimmer switches catch the worst of it, mud, salt etc. that's the first place I'd check.
 
Thank you so much for all the responses. I will report back my findings sometime this coming week.
 
The first thing I would check is power from the light switch to the dimmer switch. If you have power to the dimmer switch then check power going to the lamp themselves.

Wiring for the headlights is pretty simple. Power first goes to the light switch, from there to the dimmer switch and then out to the headlights, so trace the path for power all the way. If you have power all the way then check grounds.

Grounds are just as important as the power supply
 
I have a '47 and have rewired the headlight circuits. It may help you to know more about the 1946 -1948 dash board light switch, which may or may not be the cause of your problem. Certainly checking for proper connections and grounds is a given.

In the '47, inside the engine compartment on each side of the radiator is a small black Bakelite screw terminal board that has headlight and parking light wiring connections .... worth a check.

Behind the dash board, the body of your dash board light switch has five connection terminals hidden on top of it .... three terminals on the drivers/left side and two terminals on the passenger/right side. If stock, each of the five terminals has a wire factory soldered to it and each of those wires are about 5 inches long ending with a bullet snap connector to the under-dash wiring connections. Important: If stock you have a pair of circuit breakers under the dash on the fire wall. One circuit breaker powers the high beams and the other breaker powers the low beams, parking lights, etc. Separate wires run from these two breakers to two terminals on your your dash board switch.

All that said: If the circuit breakers and your parking lights work, but your low beams do not (both are on the same loop), then the focus of the problem most likely is inside your dash board switch, or as others have said here - inside the floor switch. Using a volt meter you can test all these connections to find where the "supply" dies.

If you eventually find that the dash switch is faulty, I have a functional one for you.
 
Thank you paul and Dr. I am going to check the dimmer switch first and then the dash switch. Great information. I will report my findings, and will give you a holler Dr if I find the dash switch is bad.
 
Just want to report back my findings on why the headlights won't come on. They have never worked since I got the car. I had assumed I had a wiring problem and started checking for voltage as suggested above. I have power to the light switch and to the dimmer switch and just found I have power to the headlight bulbs. Low and behold, both bulbs are not working. I have a little over 6 volts going into the bulbs on both the high beam and low beam. I think that proves I have bad bulbs. I don't think it can be much better than that, so I will happily go find some replacement bulbs. I want to thank everyone for your help in diagnosing the problem and guiding me through the process. I have never used a multimeter before, so I learned a lot. Thanks again for your support.
 
I'd head on down to your nearest O'Reilly's or equivalent, and ask for a couple of 6006 headlight bulbs, assuming the car is of the 6v variety. DD
 
The only common place for both bright and dim is the dimmer switch. They are exposed to the weather, and fail frequently. If you check the input from the headlight switch on the dash to the dimmer, and don't find power, the switch may be faulty. If you have the "breaker" box on the firewall, it may be the source of the problem. It was designed to pulse the headlights in the event of a short so you could get home. There are excellent wiring diagrams for your car in the club's fine 1941-48 book to help you trace the trouble.
We bypass the box and insert a modern breaker in the circuit.
 
Blown Headlights

Times change. Blown out headlights say your car was used a lot at night by the previous owner(s).

Not so anymore as politicians think you can't see oncomming cars in the daylight unless it has it's headlights on, so they mandate 'lights on all day' to prevent head on collisions. Used to be headlights in daytime meant you were in a funeral procession and if you weren't you got a ticket or at least a warning. Aargg sigggh. Oh they have stock in headlight companies you say. OK
 
Got my headlights at O'reilly's. They first told me they could not get any for an antique car and I told them the part number is 6006. She found that number and ordered them for me this morning, I got them at 4:00 this afternoon. They are installed and work perfectly. The cost was $9.99 each for a grand total of $21.88!
Thanks COOPMAN for the part number or I would not have gotten them today for sure, and certainly not at that price.
 
You must log in or register to reply here.
Back
Top