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wmarcy528

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30 Ford Tudor sedan. Headlights not working. Turn signals which work through the cowl lights and are wired direct to the terminal box. Took off headlights shell and cleaned off rust. Battery is new. Runs good but ammeter doesn’t show any change with lights switched on. Ammeter shows 7-8 when reved up. I checked wiring for any frayed wiring or grounded out wires. Could I need a new light switch?


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Could be loss of ground connection anywhere between frame rail and headlight buckets - bar, fender, bracket. Turn lights on and jumper between bucket and frame. If they work then you can narrow it down. If not, then maybe you need to work on the switch.

Could also be loss of voltage inside the bucket.
 
Have you checked for power at the lights ? Get out the test light.
If there is no power, then you need to get some.
If there is power, then just like BP said, it could well be a poor ground. And there are only about a bizillion places to lose a ground.

Rarely does a switch need to be replaced, its usually easier just to fix it.
 
Multi-meters are relatively inexpensive now days and they are the best tool a person can have for testing electrical systems and components. 12-volt test lamps are common but I don't know if they will even light the lamp on 6-volts. A multi-meter will test voltage, amperage, and Ohms for resistance & continuity.

The park light circuit that normally functions the cowl lights is part of the main light/horn switch system. I would question whether the old park light system is still involved in any way with the turn signal addition. The cowl lights are normally only a single element bulb but park/turn bulbs are dual element for bright operation of the turn signals and dim operation of running and park lights.

The turn signal input power is usually at the signal stat. I would connect it to the generator/alternator with a fused wire. The terminal box is really too crowded to start adding stuff in there or to the ammeter. Headlight power comes from the generator/alternator output connection as well as the horn power. Common power is fed into the main light switch to power all normal running lights, brake lights, park lights, and head lights. If there is power to the headlight bulb sockets then there has to be a good ground to the frame & back to the battery ground which is the normal ground path for all electrical components. If the headlight switch is on and there is no power to the headlight sockets then either the wiring or the switch are suspect.

Even though all the lights, with exception to brake light or lights, share the same switch, I always treat each individual light function as a separate circuit. Headlight function has two related circuits for low beam and high beam with the switch controlling which one needs to be selected. Adding a turn signal switch adds new circuits but it should have no effect on head lights.

Link for original electrical: https://www.mafca.com/downloads/Seminars/2018 Reno Electrical System Alex Janke.pdf
 
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With ignition key on should I be able to light a test probe that is grounded and the probe on one of indents on the light switch wiring harness?

I used this method with center horn indent on the light switch wiring harness and the probe lit up. Nothing on the lights?


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There should be power via the yellow wire, see the attached wiring diagram.
 

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I have current everywhere except headlights and taillights. Took off headlight lens and took out headlight bulb. With key on and light switch turned to high beams no power in socket? Any suggestions? Thanks


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wmarcy528 said:
I have current everywhere except headlights and taillights. Took off headlight lens and took out headlight bulb. With key on and light switch turned to high beams no power in socket? Any suggestions? Thanks


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Click to expand...



Work your way back with the test light until you find power in the circuit. You now have the wiring digram. The headlight connectors are a royal, err, very problematic.
 
The ignition switch in a stock model A only turns on the ignition circuit. Ford made them this way for a long time. In later years, they added the instrument circuits to the switch function. The ammeter was always between the generator (load) and the battery so it was the only electrical instrument from the model T days up into the early 30s.
 
wmarcy528 said:
With ignition key on should I be able to light a test probe that is grounded and the probe on one of indents on the light switch wiring harness?

I used this method with center horn indent on the light switch wiring harness and the probe lit up. Nothing on the lights?
Click to expand...

Ignition key and horn have nothing to do with lighting. Key sends points ground to coil, horn is powered from the gen; you were reading voltage in middle of the switch from the horn.
 
If you're not using a test light, thats fine. A 12v test light will work on 6v, it'll just be dim.
A DVOM is a good/great thing to have, but, some folks don't and the test light is cheap and about all a Model A needs. Ya gotts to be able to read voltage somehow.
 
Light emitting diodes generally don't make much heat since they only put out visible light but at a much higher lumen level, they make enough heat to cause damage to the semi-conductor material even though heat is much less than what quartz halogen types which also put out infrared light as well as visible light.

This active cooling set up requires more power so the savings in wattage is still better than quartz halogen but more than a bulb with passive cooling such as a heat sink. It likely takes a special socket or connetor plug.

The Logo Lites focused beam LED bulb has advantages for installation and voltage function as well as no polarity limitations. It appears to have passive cooling so would likely use less wattage. I have no idea on longevity though. It will take a while to get reports back from folks using them. The price is high but isn't everything now days. As long as thay last a number of years then the price could be in an affordable bracket.

There are non focused types in two power ranges that would likely use slightly less wattage that the focused type and have the same advantages. They use the reflectors more due to the design and the diodes are physically attached to a large heat sink. the price is about the same as for the focused type. I don't know how well these work with the stock reflectors.
 
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