Came out to call. Customer said AC wasn’t cooling and the heater was causing the breaker to trip. I checked system over and found that the heat strips and AC were coming on at the same time. Went through wiring to make sure nothing was wired wrong. Checked thermostat wiring as well. Once I checked wiring, I went to the components. I turned system off and heat strips were still coming on. Fan would kick on and not shut off. After running through diagnostics. I found the double stacked sequencer was passing voltage to the heat strips without it calling for it. Discussed with customer about repair. I replaced sequencer and wired it in. Checked both heat and AC to ensure system was working properly.