headlights dim/ 53 f-100

[flathead 53]

my headlights are very dim ,on my 53 f-100, 6 volt, truck has all new wiring , getting 6 volts at battery , rear tail lights are bright , grounds are good , getting 4 volts at head light sockets, not sure what to try next.

 

[marko39]

Check voltage in and out of your switch, should narrow it down.

 

[alanwoodieman]

corroded connections. clean your ground wire connections anyway, I had trouble with grounds in a 52 and finally ran a ground wire directly to the frame, problem solved

 

[supereal]

That is why I use 2 relays (high & dim) to operate my headlights. By the time the power goes through the dash switch, the dimmer switch, and a handful of the "bullet" connectors, the resulting voltage is inadequate, thus the 4 volts you mentioned. Now my headlights are as bright as new. It doesn't take much resistance to soak up voltage In Ohm's Law E=IR. Thus E (voltage) is the product of I (amperage) and resistance (R). My unit is mounted at the left front under the hood where the main headlight junction is located. The relays are operated by the original circuit, and provide full battery power to the headlights so after dark driving is safe.

 

[koates]

Yes need to find a 6 VOLT twin headlight relay to feed both high and low beam headlights. Very important to supply a heavy gauge power supply from the battery side of the starter solenoid to the relay battery terminal. The relay outputs will then feed the lights directly with next to no voltage drop. Regards, Kevin.

 

[big job]

As Koates wrote; there are many relays on ebay. with reasonable prices. The one you
need has 5 terminals #1 terminal power 'heavy gauge wire' next terminal low beam
in next terminal low beam out next high beam in and high beam out this relay is the
best one. I wouldn't call this a band aid cause many vehicles had these from the factory.
sam

 

[JayChicago]

Possible/maybe simple fix:
Could be corrosion on the seldom-used dimmer switch's internal contacts. Step on the dimmer switch a couple dozen times to clean the contacts.

 

[Aarongriffey]

All good advice posted above.
Here’s what I have hound several times, including on my F1.
Turn the lights on, wait a full minute and cautiously touch the headlight switch under the dash where all the wires connect to the light switch.
If it is too hot to touch you’ve found the problem.
Most light switches will get warm but not too hot to touch.
If you can not find a replacement switch that you are satisfied with then it’s relay time.
Make sure the wire to dimmer switch and the wires to headlights are at least size 14.

 

[supereal]

For relays, I use 6 volt starter solenoids. They are heavy duty and less expensive than a comparable relay, even if you can find one with a 6 volt coil. We buy them at a local NAPA store. Our other uses include the top control for my convertible top.

 

[meric42]

That is why I use 2 relays (high & dim) to operate my headlights. By the time the power goes through the dash switch, the dimmer switch, and a handful of the "bullet" connectors, the resulting voltage is inadequate, thus the 4 volts you mentioned. Now my headlights are as bright as new. It doesn't take much resistance to soak up voltage In Ohm's Law E=IR. Thus E (voltage) is the product of I (amperage) and resistance (R). My unit is mounted at the left front under the hood where the main headlight junction is located. The relays are operated by the original circuit, and provide full battery power to the headlights so after dark driving is safe.

I agree with the above and have bought NOS period correct relays through eBay but if you are not to worried about the look I have also used these with good success.

https://www.amazon.com/gp/product/B078TDWV8R/?tag=atomicindus08-20

Combined with 6 Volt quartz halogen bulbs my lights a as good as or better than a lot of more modern cars.

 

[flathead 53]

I have six volts going to the head light harness right were they connect to the head light wires to crossover wiring , but checking voltage at the headlight plug I get 4 volts, the problem must be some where ,in the cross over wiring

 

[JayChicago]

I have six volts going to the head light harness right were they connect to the head light wires to crossover wiring , but checking voltage at the headlight plug I get 4 volts, the problem must be some where ,in the cross over wiring

Good info! That's the proper way to diagnose an electrical problem: test so you can narrow-down and isolate the problem to one area.

I'm not familiar with the '34 headlight loom so can only suggest general trouble shooting ideas. Continue with your voltmeter until you can isolate further. (meter ground lead to a good ground) Do you get the 4 volts at both headlights? If you wire brush and use contact cleaner on every connector and then test the voltage after each cleaning, you may find the problem.

 

[JSeery]

I put this together a while back if anyone is interested.

 

[flathead 53]

checked all connections ,and grounds , all good . checked head light sockets with power on ,both sides 6 volts , installed one seal beam on driver side ,now checked pass side socket reads 4 volts, with no lights installed reads 6 volts at both sockets. what could it be?

 

[aussie merc]

check the harness there must be a 'Y' junction in there somewhere [left/right join] you will probably find its corroded or worse still someone has stabbed the harness leaving a hole in the insolation waters got in and caused localized corrosion to the wire [can be a bugger to find so look for a bulge , soft spot, any change in the shape of the wire ]

 

[Steves46]

Possible/maybe simple fix:
Could be corrosion on the seldom-used dimmer switch's internal contacts. Step on the dimmer switch a couple dozen times to clean the contacts.

This was the problem I had when I first got my 55 F100-cleaned the wire connections (which are exposed to the elements) and had nice bright headlights.

 

[Bluedot]

WD-40, used conservatively, is great for cleaning contacts (and about a million and a half other uses)

 

[corvette8n]

Got a set of contact cleaning brushes from NAPA, used them a lot when I had my Corvette, not sure why but most of my connections on that car were very corroded, some so bad I had to splice in ground wires on each side of the connector. Use something like this to clean your sockets.