Got 1986 Toyota Pickup(22R)... driver's side head lamp dim, but the other is fine. I've switched them out & cleaned terminals, but driver's side still dim. Stripped conduit that runs behind radiator & traced to fuse block, but no cracks, ground, etc. Having trouble locating ground... where? switch? fender? this problem must be typical & easy fix.

Other issue is the engine rpm. When warm the engine won't hold it's idle. It drops rpm & dies once warm. Starts fine when cold, but after it dies it usually takes a few minutes before it's able to start again(flooding?). The fuel level in sight glass was high, but seams to be back to the middle after I retightened carb mount bolts/nuts(vacuum leak?). It's a rebuilt carburetor with around 20k(not float level... I hope!) & I've since removed the air injection manifold & plastic resonator chamber(affects?). Good luck out there.

 

As for the headlight, it sounds like the ground is bad. I know someone will come along and tell you how to check it with a multimeter, but try a piece of wire and ground the ground and see if the light brightens.

 

How about high beams? Same problem? Busted fuse will do that. There is a fuse for each side headlight. When on fuse is busted, the light for that side will not go completely out. Leakage current from other side will run through high & low beam filaments (now connected in series) to ground, causing dim light.
Schematic for 86 - 88 is here. (Trace in red is current path for high beam, but you can just ignore that)

Note 2 separate fuses for left and right headlights.

Next to our senses, a multi-meter is the best diagnostic tool for our classics. If you don't have one yet, Harbor Freight is your friend . I recommend getting the one with clamp-on ammeter. It's handy for checking current for troubleshooting, say... cranking system or headlight circuit.

Put Neg probe on battery negative.
Turn on headlights.
Measure voltage with red probe at terminal 3 of each bulb. readings should be exactly the same.
Verify: disconnect connector from bulb, Keep headlights "on". Both terminal 3's should have 12V. Side that does not may have busted fuse or bad connection to headlight relay.

Once you're done troubleshooting, you might consider rewiring headlight circuit (mod on my signature is clean, robust, and is the one more step that Toyota engineers should have taken to do the circuit right. If not comfortable swimming in wires, just get a drop-in H4 conversion harness.

Best of luck

 

Headlights share a ground wire, located in the drivers side kick panel. They splice together before the A2 connector, A2 is located at the relay block in the engine bay. Problem has to be in this section of wire or the plugs. Sounds like it's time to upgrade to a better harness with relays, or atleast thats the excuse you can give the accountant to get you funded.

Sorry I don't do carb work Assuming everything else is adjusted correctly you just need to adjust the warm idle.

Get your manual out and follow the trouble shooting list.

 

thank you I'll jump on that & post results asap. "diligent hands rule"

 

Turns out the carburetor 4-pin green connector to the carburetor/solenoid had a loose terminal. I peeled out the round rubber insulator & pushed 'em back in with needle nose pliers & now the idle stays consistent at stop lights. I read elsewhere there's a way to hook one of the two wires from solenoid straight to battery; prevents stalling at idle & erratic idle during deceleration. Lights still working progress.