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MGB Headlights won't work after full repaint/restoration... what am I missing?

Parker

Freshman Member
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I recently got my car back from a full repaint and body panel restoration. Prior to painting, I'd disconnected and removed all chrome & lights. The repaint included boot and bonnet areas. I've reconnected all of the bullet connectors and have reinstalled the lights, using light emery paper and dielectric greas on all contacts. The following things work just fine: horn, wipers, blower, brake fault light, directionals, brake lights, igntion indicator,and high beam indicator/high beam headlights but ONLY when I activate the "flash" function using the "tree." The following things don't work: headlights, side marker lights, license plate lights.

I get full power coming into and going out of the dashboard's headlight switch. I know the headlights are properly connected because they go on when I use the "flash" function. I've heard that a repaint can cause problems with grounding, so I took extra care to clear the paint away from the license plate light's ground post. I checked the owner's handbook for any information on which of the fuse controls the headlights, but can't find the headlights specifically assigned to a particular fuse on the block nor any inline fuse for the headlights.

It's probably something simple... but after a few hours of methodical messing around, I'm stumped. Does anyone have any thoughts on what I should be doing/checking? Thanks... Parker
 
The headlights are not grounded at the rear license plate mounting bolt, if I remember correctly is it somewhere in the engine compartment. Check under the slam panel as the headlight ground wires join together with a single ground wire that goes back into the engine compartment.
Cheers,
 
And of course make sure the ground has access to bare metal at the body. If the bolt is painted over it could still not ground well unless a bit of paint is removed.
 
2 areas to check. Park lights etc are fused. Check the red wires at the fuse box for power with the switch to the park position. The headlight issue may be the power to the dipper switch. I think the power for the flash comes from a brown source and the headlights are on the blue circuit. Headlight ground is not a issue since the flash does work. Good luck finding the gremlin! Bob
 
Remember, you have Lucas Wiring, and if you have an ohm meter, check from one end to the other. IE Switch to headlight connector for continuity etc., and you can check for voltages at these locations. If you don't have continuity or voltages, you have a place to start trouble shooting. And, go about it systematically with elimination processes.
 
If they worked before you had the car painted and not after, it would seem to be fairly clear you have a ground problem. JMHO. PJ
 
This is another one of those questions that basically says, "I have everything right, but it doesn't work." If everything were right, it would work.

The way to solve these problems is to open up a wiring diagram and get a voltmeter or test lamp and check for voltage at every point where there should be voltage. Start at the switch and make sure there is voltage on the output terminal AND the wire connected to it. Then go to the opposite end of that wire and make sure there is voltage there, at the wire AND at whatever terminal it connects to. And so on. Sooner or later, you'll find a place where you lose the voltage, and that's where the problem is.

In my opinion, it's a mistake to deal with electrical problems by randomly trying things that might fix it. By systematic troubleshooting, you can find the problem in minutes. The nice thing about electricity is that you can do this kind of troubleshooting; you can't do it, or it's much more difficult, with other parts of the car.

By the way, what kind of car are we talking about? Some kind of MG, I assume, but your icon shows a TR3.

In most early MGs and Healeys, the headlights were not fused. But if you're convinced that the headlights are OK because flashing the high beams work, why are you worried that a fuse might be blown? Do the high beams work OK when the headlights are switched on, or are both the highs on lows nonfunctional? No point in troubleshooting a part that's working.
 
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