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EFV-8 Club Forum / General Ford Discussion / Dim Headlights

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Posted By Discussion Topic: Dim Headlights -- page: 1 2     louganser 08-06-2010 @ 7:43 PM reply profile send p.m. Member Posts: 39 Joined: Feb 2010 Just discovered that the headlights on my '47 Ford are as bright as candles. The car has been restored and has a new wiring harness. I suspect that the generator isn't working properly, since my almost new battery also runs down quickly. How do I check the output of the gen? Lou G supereal 08-07-2010 @ 12:50 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Place the leads of a voltmeter across the battery posts with the headlights turned on and operate the engine at a fast idle. If you see more than about 7 1/2 volts, the system is overcharging, and will cause damage to the battery and other sections of the system. If the reading is below 6 1/2 volts, either the generator or the voltage regulator is suspect. Most of the time, the last thing you do to a car is the cause of a problem. Double check your wiring and connections. Many new wiring harnesses are made up to fit several different years and models, and may have a wrong or missing circuit. If the charging rate seems OK, the problem is in the lighting circuit. itself. louganser 08-07-2010 @ 7:24 PM reply profile send p.m. Member Posts: 39 Joined: Feb 2010 Thanks! I'll give it a try. Lou G proxie35 08-10-2010 @ 6:03 PM reply profile send p.m. Member Posts: 74 Joined: Jun 2010 I had this same problem after I completed restoration of my 50. Everyone said it had to be the Grd. All the Grd checked good, even to the last point, to the headlight bucket. I could disconnect one headlight & the other was BRIGHT. After days of checking, I found the Grd. wire was plugged into the wrong slot, of the plug to the Headlight Bulb. All wireing was new. 12v system. louganser 08-19-2010 @ 6:41 PM reply profile send p.m. Member Posts: 39 Joined: Feb 2010 I took the car to a generator shop. The gen and volt. reg both tested VG, the gen putting out just over 6 volts. The wiring harness is new (car was totally restored in 2003) and all connections have been checked. I pulled the headlights and checked the connections...clean. I removed the groung wires, sanded the sh*ll to bare metal for a better ground and reconnected the grd. wires. The lights are s little brighter, but still not great. Maybe it's just that they're 6 violts? By the way, none of the dash lights work either. Lou G trjford8 08-19-2010 @ 8:02 PM reply profile send p.m. Senior Posts: 4214 Joined: Oct 2009 Lou, there is a dimmer for the dash lights. It's on the bottom left side of the dash. Rotate the knob to see if the dash lights come on. It may be turned to the point of shutting off the dash lights. If your headlamps are grounded inside the buckets they may not be getting a good ground. Run an extra wire from the bucket to a clean spot on the frame to see if this helps. sturgis 39 08-20-2010 @ 5:07 AM reply profile send p.m. Member Posts: 74 Joined: Nov 2009 I HAD THE SAME PROBLEM WITH MY TAIL LIGHTS.I HAD 12 VOLT BULBS INSTEAD OF 6 VOLT. 37RAGTOPMAN 08-20-2010 @ 6:43 AM reply profile send p.m. Senior Posts: 1961 Joined: Oct 2009 ALSO TRY.!!! if everything else fails try some NEW HEADLIGHT BULBS, AMERICAN MADE, you never said that you changed them, they might have a problem inside due to AGE. you can try a test wire 14 gauge, from the ground battery to the headlight bucket or the ground connection on the headlight bulb connection, and see if they get brighter,try both beams high and low hope this helps, 37RAGTOPMAN,an KEEP ON TRUCKIN,,!!!! hope this helps TomO 08-20-2010 @ 7:47 AM reply profile send p.m. Senior Posts: 7252 Joined: Oct 2009 Your voltage regulator should be adjusted to put out 7.2 to 7.4 volts. Anything less than this will not charge your battery. Check the ground connections on the regulator and the generator. Check the voltage at the headlights when they are on and the car is running at a fast idle (about 1500 rpm). You should have at least 6.5 volts at the headlights. Use a voltage drop test to isolate the source of low voltage. A voltage drop test is performed by connecting the COM or - meter lead to the battery and the POS meter lead to the headlight wire at the bulb. The meter should read less than .2 volts with the lights on. If it is more than that, move the POS lead to the dimmer switch and then to the headlight switch to determine where the resistance is. The dimmer switch, headlight switch and bullet connectors are all causes of excessive resistance causing a voltage drop at the head lights. If the voltage drop is within specs and the lights are still dim, use the same procedure to check out the grounding circuit, by changing the meter lead connections to the POS lead should be connected to the POS battery terminal and probe with the COM or - lead. Tom supereal 08-20-2010 @ 12:10 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 The root of the perennial dim headlight problem is that the wiring and controls were initially designed for the old bulb and reflector system, and were never upgraded to handle the load of the sealed beams. Two of those drawing about 50 watts each require a minimum current of about 18 amps at six volts for proper illumination. If you replace the lamps with halogens, the power requirement doubles. Couple this with undersized conductors (wiring) and the number of switches and connections between the battery and the lamp, and the result is dim lights, in most, if not all cases. Converting to 12 volts in the 50's decreased current requirements by about half, allowing brighter lights with the same gauge wiring. If the connections are clean and tight, and you have enough headlight brightness to get home at night, that is about as good as it will get without substantial revision of the system.

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