1980 toyota pickup with 20r engine headlights quit working but all other lights work and no blown fuses can i find a wiring diagram free online someplace

Did you check for voltage at the 50 amp fuse circuit. Even if the fuse is good if no voltage on the fuse circuit, the circuit is still dead. There is a light green wire that carries voltage from headlamp switch to dimmer, is that wire hot with headlamp switch on?

There are wiring diagrams for free, just about everywhere, if you don't have one. Autozone .com has free wiring diagrams on vehicle repair guides link. You have to register your vehicle, year--make--model, all that good stuff. It's free.

main power issues .. check battery connections.. check fuseable link wires under hood,..check fuses in fusebox for blown fuses and check wiring harnes ground connections especially by the headlights..

Try checking both a; your fuses, and b; check your bulbs. You should have two fuse boxes, one under hood and one in or under the dash. Check those for bad, blown or weak fuses. And check your headlights bulbs for them being good and their connection. If this doesn't fix your problem, you may check out your highbeam switch.

visit this link i used thes for my 1980 toyota pickup and they work perfectly hope this helps

Yes & no
Down load a service manual for your vehicle from this website

It will describe where everything is and how things work correctly

http://ezinearticles.com/?Find-the-Free-Auto-Repair-Manual-You-Need-Online&id=92717

Try checking for a blown fuse in the fuse box.

run to autozone and buy the Haynes repair manual if they have it its in the back

replace gray flasher relays under driver side dash, should say "Flasher" right on them, they may be either round or square.

If you have a 22r carbed then all 22r carbed engines from 1981-1995 will interchange. You may need to use sensor out of your old engine however. The 20r,22r,22re,22ret all have the same mounts and tranny bolt patterns. how ever there are lot of differences. you can swap from a 22r to a 22re but you must also swap the entire vehical wiring harness to do it right. if you have a 3.0L i would keep the same engine. some people have swap to the tacoma 3.6L but that is a expensive swap not exsactly bolt on so to say. If you have a 22re then stay with the 1986-1987 22re because the newer 22re use different computers, electronics ,sensors and more.. Same story with the 22ret. I hoped this helped.

if you have a manual or a trouble shooting book, locate the wiring diagram for the headlights, sometimes there is an in-line fuse or relay located on the vehicle somewhere. there has to be a fuse somewhere i promise. start from the headlights, try to chase back until you get under the dash. normally the wiring will be bunched up into a (compact type) or bundel, worse case senerio, split open bundel to expose all the wiring. there is sight that may help you. autozone znet.com