My both turn signals flash fast at the same time

Hello,

It sounds like you have a turn signal switch that is shorted or hazard flasher which is the turn signal flasher that is out. They had big problems with the unit in these cars.

Here are some guides so you can confirm the issue test through the switch using the wiring diagrams below.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Diagrams (below)

Please let us know what happens.

Cheers, Ken

Check your bulbs first then it may be the flasher which is an integral part of hazard switch near center of dash

I have seen this problem before it is the turn signal switch.

Hello there,

You're probably dealing with a bad flasher unit (hazard switch). It's a common occurence on Impala/MonteCarlo. A new unit runs around $35-40 if I remember correctly.

Replace the binker unit, in that car I beleive it is the hazard switch. Please let me know

Intermittent issues are hard to diagnose, could be failing turn signal switch or sticking flasher signal relay most likely culprits.

The flasher is the 4 way switch on dash. Have it checked.

Roy