There are no computers or relays between the front and rear turn signal bulbs - IOW, If fronts are working and rears are not, has to be a wire, connector or bulb issue (both bulbs blown?).
From a post I did a week or two ago:
Flasher - under dash - remove driverís side knee bolster. Itís on a panel with some connectors. Itís black - towards bottom left of that panel IIRC. Flasher can be difficult to remove. Most people abandon it in place and pull the connector off and plug in the new flasher and zip tie it to some nearby wires. But if you remove the screw that attaches that connector panel to the underdash structure, you can stick a screwdriver into the latch slot that secures the flasher to that panel to unlatch the flasher and remove it.
Most aftermarket flashers, even though listed for our cars in the applications lists, do not work properly on our cars - some even blow one of the fuses every time you use the hazards. Best to get the OEM flasher from the dealer or from a junk yard.