blinker out
Did you check all of your dual element bulbs? A good way to tell if one's out is to put your 4-ways on and see if the left is the same intensity as the right. There are two dual elements in the tail light and I'm not sure what's up in the marker but I would check that out, too.
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be carefull with them muffler bearings also 
Replace the bulb for front the blinker on the side that has the issue, if you still have an issue then replace the back bulb on the same side for the blinker (in the back of the car). Had the stuck on (no blinking) issue with my blinker several times, the bulbs are cheap so I recommend you just buy them both and I just did it in parking lot (caution you will need long arms lol).
Here's a thread about what Phoenix57 was talking about, there's good information here. I bet this will probably fix your problem:
Thermal Blinker Thread
I also have a right blinker problem and thought it was a bulb in the rear. I replaced it and it was fine an hour and then stopped blinking again. Then I thought that the harness was corroded, so I steel wooled the hell out of it and put some silicon grease in there and put the bulb back in. It was good for an hour, and is not working again. Now I'm thinking it could be a loose wire or something in the harness. I use the 4-way trick to check them and its the same bulb every time. A couple years ago, my tail light housings failed and took on moisture to the point that I could have had fish living in there.
I put the newer 98-02 style lights on but never replaced the harness. Maybe that moisture problem is finally starting to kill the harness behind what I can see. Anybody ever have harness problems? 

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