When it hasn’t been driven for a while and when its cold outside the turn signal stays on and wont flash. Once after quite a few miles and when the engine has warmed up the turn signals work properly and flash when they need to.
This Problem of the Turn Signals on your 2000 Malibu is Due to malfunction of the FLASHER RELAY
The Flasher Relay is Part of the HAZARD SWITCH. Located on the instrument cluster BEZEL.
The GM part Number is : 22594146
The Best Place for the Flasher Relay COST is aprox. $ 26.00
Source: Fixya.com