FWIW, I see three distinct problems. The check engine light is coming on, notifying you that a fault has been found that is effecting the emissions specs of the car. Check for a code(s). This you can do yourself. The right turn signal flashes fast because the lamp is not happy with one or both of the bulbs regardless of how they "look". Replace both the front and rear right turn bulbs to be sure. Lastly, if the right side interior bulbs are dimmer, ask yourself if they have ever been replaced, and if so, with the exact same type as the left? If not ever replaced, go to the dealership and get the OEM bulbs and replace them and go from their. In other words, for the small cost of bulbs, do all the simple stuff first before assuming their is a short or worse. Good Luck and let us know...
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'82 240DL Stock / Masters Class, '94 850 Fully Loaded / Daily Driver, CVC / VCOA Member