High Beam indicator?

LEDs have a higher resistance. That's why they use less current. You added a circuit in parallel so it reduced the overall resistance of the circuit.

 

Correction: LED bulbs use electronic circuit ("driver") to power LED chips. That circuit does not behave like a resistor (or incandescent bulb). At low current most of them will shut off and stop taking any current (unless LED bulb is dimable).

The truth is that adding resistance in parallel you allow the indicator bulb get some power to turn on. The clever Toyota design that simplifies the circuit for incandescent bulbs (and crappy at the same time because it is running full current through the switch by the steering wheel) bites you in the ass when trying to replace stock bulbs with something different (HID, LED or high power halogen).

 

What annoys me, Toyota already figured out how to do it correctly in their DRL version. It has separate 10A fuse for each bulb's filament and relays for high amp circuits. In that part the Canadian wiring is so much better. I'm jelly.

 

I'm referring to Tacoma manufactured for Canada where DRL are required (The Motor Vehicle Safety Act dictates all vehicles sold or imported into Canada after Dec. 1, 1989, must have automatic daytime running lights (DRLs)). DRL version of Tacoma has completely different circuit diagram and connections for headlights. Dimmer switch is controlling lights through DRL Relay and all high current is going through relays only. Very same circuit could be adopted without DRL functionality (by removing few elements) but still keeping relay-switching high current circuits.