A/C light blinking engine struggling

2017 Tacoma manual 4cyl. When air is turned on ac light flashes and engine loses power. I can hit the ac button to turn it off and air works fine, both hot and cold. But if I switch modes from defroster to floor the ac light will flash and engine will drag. Ac works intermittently.
Any suggestions on where to start looking first?

 

Welcome to Tacoma World. First thing I'd be looking at if it were mine is the A/C compressor clutch. Seems to fit your symptoms, when A/C is turned on if the clutch is locking up and causing extra drag on the accessory drive belt it will load the engine (and probably chew up your belt too), then when it is turned off the load goes away. There should be some threads on this if you search a bit, good luck.

 

https://www.tacomaworld.com/threads/ac-clutch-failure-how-to-fix-blinking-light-squealing.448009/

 

Welcome to TW...