Topic: 81 pickup no power to headlight

[yotacorps81]

I have an 81 Pickup and  am getting no power to the driver side headlight. I have checked power from the switch on the steering column to the relay under the dash and I am getting 12.45 volts there. I unplugged the relay and checked power at the headlight and I am getting .02 volts which should be 0.0 if I'm not mistaken. I ran a wire from the hot side where the relay plugs in to the low-beam side and checked the voltage at the headlight and am getting 0.03 volts. I thought that it might be the plug that goes on the back of the headlight, so I cut that off and bought new ones but didn't install them yet. I am getting all of these readings straight from the wires. I did the same thing to the passenger side, and I am getting 9.45 volts to the headlight so everything seems to be working on that side. I have no idea what else it could be or what else to check... Any ideas?

[Cheesemaker]

You should be getting 12+ volts at the wire in the plug.  Here's what I would do, I would start with the ground wires, and test for conductivity through the wire.  Use your volt/ohm meter, put the leads on each end of the wire.  You should see 0 resistance.  If you are getting resistance, your wires are getting corroded/weak.  Alot of factory wiring has scrimped ends, not sealed ends.  Moisture and and dirt gets in there and causes issues, attacking the copper wires.  Alot like when your battery terminal gets all corroded.  I'd start with the ground wires and work my way back.  Testing each and every wire that goes to the headlights.  Another thing to do, is to check where the ground bolts down too.  Make sure they are clean. 

[yotacorps81 [OP]]

Thanks alot Cheesemaker! I never thought about the wires being corroded... I had to replace almost all of the wires goin to the plug, but my headlights work now! Thanks again!