The turn signals stopped working one at a time over the last year. The first one to go out was the drivers side and it would work as long as I manually clicked it. So now they both don't work. Also the dash indicator for the L turn signal stays dimly lit on the dash.

Check the wiring from the signal stalk

What make , model an year vehicle ?

Well, it's not really clear what the problem is with your turn signals. If they just aren't flashing, there's a good chance it's caused by one of three things... Either the flasher its self has gone bad, or on most vehicles, if one of the turn signal bulbs have burned out, the signals won't work on that side. Lastly, the simplest cause... The turn signal fuse!
The flasher relay can usually be found either plugged into the fuse block or under the dash on the driver's side. It's usually silver or yellow and is about 1 1/2" round and about 1 1/2" high with two prongs. Just unplug the old one and plug in the new.
Good luck and Happy New Year,
Bill

check the wire loom from the boot to under the back seats, I have herd over time the back seat can cut the wiring loom as the metal in the back seat can cut the wires. saw this on a classic cars site a few years ago. you will need to fix the wires back and reseal the wires with sealing tape. also make sure the wiring is back out of the way for the seat.

First check both front and rear lft side bulbs. Then, I would check the signal relay. I think it is under the dash one the left side. Here is want your are looking for. A new one cost about $12-$15 at most parts stores. Last I would suspect the signal switch assembly on the column. (Perchance you have a trailer hitch plug? If so look there too)

j

take it to a body shop

Any idea's ? Yes , learn how these system's work ! Looking at wiring diagram's to see what all is involved in the electrical circuit's for the brake & turn signal lamps . Plus learning how to test electrical circuit's with a DVOM - digital volt ohm meter .
Electric Testing Techniques You Need to Know
Testing is how to find this problem , not going by someone guessing who has not even looked at the vehicle ! Free wiring diagram's here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model an engine size . Under system click on lighting ,then under subsystem click on stop lamp or turn signals . Take your DVOM an at the rear right stop lamp bulb test for B+ voltage , check ground side . See which side of the circuit has the problem . Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia

It happened to my 98 Intrigue. It stopped as soon as I changed the sockets. It is very simple to do this, just pull it out the the plug from the connector about 4 inches from the socket. I got used ones at the junk yard, 2 bucks a piece. Been working fine for almost 2 years.

replace the turns signals flasher unit.