All lights work except for headlights. I checked fuse baox and i get no power on either side of the head light fueses. I also check for power in the seal beam connector and had not power. Please tell me someone has the answer. Thanks
Follow the FSM TS stuff. Head lights use a Fusible Link, Combo Switch and a fuse for both the left and right side... Which would mean trace voltage from batt to FL, FL to Switch and fuses. The rest is wire and sockets... clean all contacts and you can remove the headlight switch with a good Elec Contact Cleaner and clean which sometimes helps also clean the contacts on the fuse box. You might want to think about pulling the fuse box and take it to a good elec shop and have them clean it up. Replace all the fuses just cause... If you do change out the Light Switch you can get a OEM from MSA yours is prob 122 mine was 101 on a 77. Join a club that can save you 10% is worth it BTW... Just remember if you get one at a pic-n-pull it is just as old as yours the new one will last you another 20+ years...
BTW do say the year on your post Cause a 74 only has 2 Fusible Link and 75 and up have 4 of them....
Thanks for the input. I do not have any power across the fuses. But not having the proper wiring shem, I do not know if that is due to no power from the switch or does power go thru the fuse box first. I do see the fuse links. I do not know where they go from there. The only thing not working are the head lights. The parking lights, etc are fine. High beams nor low beams work and I have checked power at the light itself.
I'm betting your front side markers don't work either? They run off of the same wiring as your headlights. The power path for headlights is: BATTERY, FUSIBLE LINK (BLACK), shunt, FUSE (20A), COMBINATION SWITCH and then LAMPS.
If you have no power across your FUSE and the wiring looks alright then as previously mentioned it is most likely FUSIBLE LINK (BLACK).
The side markers work fine and come on with the first click of the combination switch. But still nothig with the head lights. I will check the fusable link. The black one has gotten hot and the insulation off of it. I do seem to have power to the switch and when I activate the switch I get power to the wire going out of the switch. I checked this with a test light. Does the switch then go to a relay or such that may be bad? And thanks for your help.
I seem to have power to the swich and when i activate the switch i get ower to the wires. Surely the switch does not carry the full power to the head lamps. Is there a relay from there? Also how about a rely for the high beam as they do not work either. All side markers do work.
I don't think there is a relay in the headlight circuit, but don't take that as the final word. It's good to hear that you have side marker lights because that means your Fusible Link should be good for your Headlights. Double check your headlight fuses for voltage on both sides of the fuse - referenced to ground.
Previously I typed, Incorrectly.....
The power path for headlights is: BATTERY, FUSIBLE LINK (BLACK), shunt, FUSE (20A), COMBINATION SWITCH and then LAMPS.
It should have been: BATTERY, FUSIBLE LINK (BLACK), shunt, COMBINATION SWITCH, FUSE (10A), LAMPS -- Turn Signal Dimmer Switch.
If your headlights are good (both high/low beams on both lamps being bad would be a coincidence) then the TURN SIGNAL DIMMER SWITCH that supplies the ground for either the HIGH or LOW beams may not be completing the circuit.
Also check the connectors at the lamps and especially at the radiator support bracket. Look for cut insulation through the cable shield and/or insulation at the radiator support bracket. Does your amp meter draw more current than normal when you turn your headlights on?
Thanks everyone for the input on my head lights. It was the switch. I hated to spend the money but I ordered a new one. I will share this though. After taking the turn signal switch apart to get brighter signals, I took the head light switch apart and after filing the contacts the head lights work great. Anyone want a new head light switch? Gues i will keep it for a rainy day project. Thanks for all the inputs.