On your car at the socket for the parking light/turn signal there is one power line and two grounds. The Orange/Blue tracer wire is actually the power wire, NOT ground. It's unclear from the wiring diagram which ground is for the turn signals and which is for the parking lights, but when working properly one of the Black wires will be at ground potential when the parking lights are on and the other will have ground at the flash rate for the turn signal. One of the switched ground wires is Black/Blue tracer and the other is Black/White tracer.
Do you happen to have a test light with an incandescent (ie: not LED) test light? If so, that might work better for some of these next suggested checks. Start by using a known good ground, such as a a bolt on the engine block, a strut mount bolt, or the bolt for an engine ground strap. I don't recall if there's a recommended remote jump start ground under the hood or not, but if there is, that would be an excellent source for ground as well. Then use the meter or test light to check for battery voltage at the Orange/Blue tracer wire. If you use a test light and it doesn't light, or it's dim, then try the same measurement with your multimeter. If your multimeter again reads something like 11.8 VDC, then this confirms you have a high resistance in the power supply line to the bulb. Try the same measurements, but at Fuse F208 (F208) in the Central Junction Box (CJB). If the test light is bright here, you need to trace that Orange/Blue wire from the bulb to fuse F208. Study any connectors, splices, and the wire insulation for signs of corrosion.
If your test light is also dim or fails to light at F208, then you have an issue with the voltage supply to the fuse socket or the fuse itself. Since you're not complaining about other front lights, it's unlikely the issue would be between the battery and the CJB so you could focus on the fuse, the connections for the fuse possibly being corroded and/or not making a good connection with the fuse, or the CJB itself.
If the test light is nice and bright on the Orange/Blue wire at the bulb socket, then switch the test light clip lead to a source of good battery power. Here again, a remote jump starting Red post under the hood would be convenient. Touch the test light probe to a good ground to confirm you have a good power source to the test light. Now probe the bulb socket black wires. One should light the test light when the parking lights are switched on, and one should light the test light when the right turn signal is supposed to flash. If the test light does not light bright in either of these scenarios, the issue is with the ground paths to the Front Electronics Module (FEM). Again, you'll need to trace the wires, concentrating on any connections, splices, and the wire insulation. Or you could go straight to the FEM and use the test light to back probe the connector to determine if the FEM is providing a nice, strong switched ground for both circuits. The wires colors do change between the bulb socket and the connectors on the FEM. The bulb socket Black/Blue wire is a Black/Red wire in connector C201c terminal location 10, and the Black/White wire at the bulb socket becomes Black/Yellow wire at connector C201a terminal location 4. This makes harness connector C133 between the bulb socket and the FEM a likely suspect if you find yourself going down the path of a bad switched ground.
-Rod