Headlights burn out

U

U.P. Ted61741

Junior Member
When I turned on the headlights they were fine. Then drove about 100 yards, the lights got very bright for a second and quit working on both beams. I suspect they are burned out but haven't checked yet. Can anyone tell me what the problem might be? My powerhouse generator was recently rebuilt and I had no problems on my last 97 mile trip but I never used the lights.
 
Almost sounds like the generator voltage started running-away suddenly, enough so as to burn the filaments. From your symptoms, I'd suspect voltage regulator/cut-out. DD
 
Because you say the lights got really bright just before the world went dark, leads me to think you a have a poor or open connection somewhere allowing the generator to 'run away' and make too much voltage.
 
Ditto what Patrick said. Check the wire terminals in the terminal box on the firewall. the nuts and terminals need to be clean and tight. The same applies to the rear of the ammeter. These are the two most common places for loose connections.

If you use a fuse, I hear many people talk of poor connections there. Did you remove the rear cover and make sure the powerhouse isn't adjusted too high? Did the shop wire it correctly? There's only two wires to connect, and the adjustable brush goes to the field wire. I've seen two Autolite style generators burned up by shops connecting the wires wrong.

I only use generators with an electronic voltage regulator used to replace the adjustable brush, then the output is always at a safe level, even if you do get a bad connection somewhere in the charging circuit.
 
You may have a poor ground on your battery where the ground cable attaches to the frame. This is the most overlooked electrical connection on a Model A. Remove the battery to gain access to the cable connection. Remove the cable and clean the mounting boss on the frame as well as the cable itself.

Tom Endy
 
Tom's suggestion is the most likely answer to the problem, however check all the battery cable connections. The battery is necessary in the charging circuit to stabilize voltage.
 
Tom Endy said:
You may have a poor ground on your battery where the ground cable attaches to the frame. This is the most overlooked electrical connection on a Model A. Remove the battery to gain access to the cable connection. Remove the cable and clean the mounting boss on the frame as well as the cable itself.

Tom Endy
Click to expand...

Smog Tech said:
Tom's suggestion is the most likely answer to the problem, however check all the battery cable connections. The battery is necessary in the charging circuit to stabilize voltage.
Click to expand...

Lights don't very often illuminate brightly with questionable grounds...usually just the opposite. Some very valuable clues here with the lights suddenly becoming VERY bright just before failure. Voltage suddenly ramped-up for SOME reason. Could even be something as obscure as a sudden degradation of a battery cell connector, or a cell itself degrading. I'd still look at the voltage regulating device after checking the battery's ability to accept AND hold a charge. DD
 
Stock Model A generators are unregulated and the voltage is ONLY held to about 7 volts by the fact the generator is connected to the 6 volt battery. Any poor connection in the charging circuit can allow the generator to go as high as 40 volts.

This is why I recommend using an electronic voltage regulator.
 
I agree that a loose connection at the battery cable will cause a voltage spike. If you use one of the aftermarket battery cable ends with a cut off knob this could be causing the problem as well as any faulty battery connection, positive or negative.
 
I had the same thing happen years ago, early in my A journey. Poor ground at the battery. Lights got very bright, then the filaments melted.
 
You must log in or register to reply here.
Back
Top