the brew light on my classic pro keeps flashing on and off while i'm pulling a shot, is that normal?

Diagnosis

Yes, that's completely normal and indicates the thermostat is working. The light turns off when the boiler heating element is actively heating and comes back on when the target temperature is reached.

How to Fix It

This isn't a problem to fix; it's correct operation. For a more consistent shot temperature, implement a temperature surfing routine:

1. Turn on the machine and wait for the brew light to come on steady.
2. Flip the steam switch on for about 5-10 seconds, then turn it off. This super-heats the water.
3. Wait for the brew light to come back on, then immediately pull your shot. The light will cycle during the shot.

If That Didn't Work

If the light is flashing erratically or never comes on at all, you might have a faulty thermostat or a loose wiring connection. That requires checking internal components with the machine unplugged.

Heads Up

Don't confuse the brew light with the steam light. The steam light (orange) only illuminates when the steam switch is flipped on and the steam boiler is up to temperature. The brew light (white) is for the main brew boiler.