Problem - Front turnsignals don't flash, rear turnsignals work fine.
Solution - Wiring under steering column is reversed - review installation steps 31 and 32 (Impala only).
Problem - Rear turnsignals don't flash, front turnsignals and dash lights work fine.
Solution - Trunk wiring incorrect - for the Impala check installation steps 28 and 29, for the Eclipse check installation steps 6 and 9, you may have the 2 white wires reversed and/or the 2 brown wires reversed - or I may have color coded the connectors improperly, simply reverse the 2 white taillight connectors, (yes plug red into blue and blue into red) you won't damage anything and if it works just change the color coding on the connectors yourself.
Problem - Outer bulb on rear turnsignals doesn't flash.
Solution - Trunk wiring incorrect - for the Impala check installation steps 28 and 29, for the Eclipse check installation steps 6 and 9, you have the brown and white wires reversed.
Problem - The center bulb is not as bright as the other 2 bulbs.
Solution - Easy fix - A note about the lamp sockets, if the regular driving/parking light comes on instead of the brake lights when you activate your turn signals - the socket can be adjusted by removing the bulb, push the red and white wires together with the black insulator up and out of the metal socket, then rotate the insulator and wires 180 degres and reinsert them back into the metal socket, reinstall the lamp.