Turn signal not blinking

That is the typical symptom of a broken ground circuit. The clue is the turn signal bulb will turn off when you unplug the other bulb that shares the same ground circuit. This is the head light bulb. Current can't find its way to ground, but it finds an alternate path through another bulb, then over to the same bulb on the other side of the car, through that one, then to ground over there.

In this case it is ground "G101", circled in this partial diagram. You should find the left head light is not full brightness. This ground wire is listed as bolted to the "left rear side of the core support, next to the windshield washer reservoir".

The rapid flashing indicates not enough current is flowing in that signal circuit. No signal current is going through the left front signal bulb. That bulb is lighting up due to current coming from the head light circuit. I'm sorry that it's hard to explain better, but check that ground wire first, then we'll dig deeper if we have to.

This is a good opportunity to gently wiggle on the wires to see if the problem acts up. If you do this in the dark, you might even be lucky enough to see a small spark occur at the bad connection. Look for a loose grounding screw, or rust around it. Tug lightly on the wire to see if the insulation stretches like a rubber band. If it does, it's because the strands of wire are burned away next to the terminal.

There will be multiple wires spliced together too from the signal light and the head light. That's a good place to find moisture has snuck in and caused the splice to corrode apart. Often that is one solid wire with the second one connected to a bare spot on it, then soldered. The signal wire is the less important circuit, so if the splice corrodes, the head light would be the one that keeps working.