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For some reason I have dim headlights on my stock 1952 truck which is 6 volt.Something I can't understand is I have 6.24 volts to wire at the harness at grill.This is on high beam.It plugs into a double connector for each side.The voltage coming out on both wires going to each headlight I only have like 3.5 voltage .Is this normal or shouldn't I have at least 6 volt going to each headlight?My battery is good wiring about 3 years old and never had this dim headlight problem up until now?Where do I start?For some reason I suspect bad light switch but just guessing?
I will watch this thread. My headlight are terrible. I don't drive at night often though.
My first thought would be do you have good grounds. That is always a good first look.
Check voltage to the bulb to see what you get as well.
You might try bypassing the dimmer switch? Or use a jumper wire to the battery to check the bulbs. Sounds like you have a bad connection coming from the switch or the dimmer switch since you have already checked the ground side.
Just an FYI, when measuring voltage with a meter, you generally are testing without a load. Headlights are one of the more higher current components in your truck and it is possible for degraded circuitry to be able to show good voltage at essentially no current, but perform badly under load.
Another thing is expectations - incandescent and halogen bulbs have a warmer color temperature which may be interpreted as dim when compared to more modern illumination which has a colder temperature.
Third, the stock wiring draws a lot of current through the switch and lengths of wires. It can be advisable to have your stock switch control a relay. Previously I have recommended the use of a pretty much drop in relay headlight harness detailed here:
The headlights should be wired in parallel so you’ll get the full voltage at each bulb.
It sounds to me like you have excessive resistance in the circuit somewhere causing a voltage drop under load. Some troubleshooting is in order.
Id start by checking the grounds. Use your meter on the lowest ohm setting you have, connect from the ground wire in the headlight to the engine block, it should read 0.
Next run the jumper as Brian suggested, directly to the headlight connector. If you get full voltage that way, work your way back through the circuit. Run the jumper to the harness at the connector by the radiator, again, if you get full voltage, go to the dimmer switch, full voltage? Go to the headlight switch, then the breaker under the dash, then the wire to the regulator.
so what to do if you don’t get full voltage on one of these tests? This means that you have a faulty wire, connector, switch, whatever component you connect to that drops the voltage.
I will watch this thread. My headlight are terrible. I don't drive at night often though.
My first thought would be do you have good grounds. That is always a good first look.
Check voltage to the bulb to see what you get as well.
I like to go to cruise nights so often have a short drive at night. I solved the dim headlight issue, but it took some doing.
First, I went to halogen bulbs, but the generator couldn’t keep up. I switched to a 6v -ground alternator from powergen, easy swap but a bit pricy. The final piece was installing a separate circuit, breakers and relays. This way, the headlight switch and dimmer switch are only there to activate the relays, eliminating any possible corrosion in the switches. I ran a wire from the breakers where the regulator would normally connect (no regulator with an alternator). That runs to a pair of breakers, which in turn run to the two relays. The relays are trigged by wires from the dimmer switch.
my headlights are so bright the folks at truck stock constantly ribbed me about blinding them.
I put a relay in mine. I run high beams all the time since they are so dull.
If you are interested in wiring for a relay, I put together a diagram for my 55. I would think the 52 isn't much different. The numbers by the lines are wire gauge I used.
installing a separate circuit, breakers and relays. This way, the headlight switch and dimmer switch are only there to activate the relays, eliminating any possible corrosion in the switches. I ran a wire from the breakers where the regulator would normally connect (no regulator with an alternator). That runs to a pair of breakers, which in turn run to the two relays. The relays are trigged by wires from the dimmer switch.
my headlights are so bright the folks at truck stock constantly ribbed me about blinding them.
The relay harness I mentioned above does this all in a drop in kit form. It plugs directly into the existing headlight sockets which control the relays, and then has an output socket that now connects to the headlights. It also has a new fussed power line for the high current lamps. Installation is basically unplugging the headlight sockets, plugging the harness into them, plugging the harness into the headlight, and connecting the one fused wire to the battery. And presto, that is it. It uses your stock wiring and switch for control.
The relay harness I mentioned above does this all in a drop in kit form. It plugs directly into the existing headlight sockets which control the relays, and then has an output socket that now connects to the headlights. It also has a new fussed power line for the high current lamps.
If only I’d know 2 years ago.
I bought a kit from Dennis Carpenter, but it was 12v. By the time I converted it to 6v I decided it was easier and more reliable to simply make my own.
Russ, If I read you first post correct you have full voltage at the radiator support (it would not matter if it was high beam or low beam, should be same voltage, it just goes to a different filament in the light) which would be after all pieces of the circuit. This tells me the switches (high beam and headlight) are good. From that connector to the headlights your voltage drops basically in half. That tells me either that connector is bad or the wire between the lights went bad. When I say bad, I mean that it has corroded or something else has happened to increase the resistance thereby reducing the voltage. That connector is where I would start and if that is not the problem I would run bypass wires to the headlights to eliminate the existing wire as the culprit.
Russ, If I read you first post correct you have full voltage at the radiator support (it would not matter if it was high beam or low beam, should be same voltage, it just goes to a different filament in the light) which would be after all pieces of the circuit. This tells me the switches (high beam and headlight) are good. From that connector to the headlights your voltage drops basically in half. That tells me either that connector is bad or the wire between the lights went bad. When I say bad, I mean that it has corroded or something else has happened to increase the resistance thereby reducing the voltage. That connector is where I would start and if that is not the problem I would run bypass wires to the headlights to eliminate the existing wire as the culprit.
Thanks Dave ,I am no electrician but I am thinking I should have at least 6 volts to the headlight pig tails?As I stated before I did install an extra ground on each bucket.I did order a new switch and for some reason I forgot to mention that the switch **** with shaft comes out sometimes when pulled like it is not latched?
