# Headlights flicker when letting off the gas **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet, sonic\ **Created:** [December 10, 2022, 7:24pm UTC](https://community.cartalk.com/t/headlights-flicker-when-letting-off-the-gas/187864 "2022-12-10T19:24:18Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![twnewland\_183286](https://avatars.discourse-cdn.com/v4/letter/t/7feea3/32.png) [@twnewland\_183286](https://community.cartalk.com/u/twnewland_183286)\ **Post date:** [December 10, 2022, 7:24pm UTC](https://community.cartalk.com/t/headlights-flicker-when-letting-off-the-gas/187864/1 "2022-12-10T19:24:18Z")
When i let off the gas and the engine drops to about 900 RPM, the lights go dim for maybe 2 - 3 seconds. The local parts store did a battery check and it is 96%. They checked the charging circuit, and it indicated a problem. I have replaced the alternator, but it is still doing it. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [December 10, 2022, 7:45pm UTC](https://community.cartalk.com/t/headlights-flicker-when-letting-off-the-gas/187864/2 "2022-12-10T19:45:07Z")
Try replacing the serpentine belt. Tester ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [December 11, 2022, 9:13pm UTC](https://community.cartalk.com/t/headlights-flicker-when-letting-off-the-gas/187864/3 "2022-12-11T21:13:27Z")
Any of these are likely culprits - replacement alternator is faulty - alternator pulley is not spinning fast enough, belt slipping etc - problem w/charging wire between alternator and battery - problem with charging regulator circuit. If you know how to use a volt meter, batteryshould measure about 12.6 volts before the first start of the day; then immediately after starting engine, 13.5-15.5 volts. What do you measure?