I have a Dreammaker 400 spa. I just replaced the pump but now the main spa light that lights the hot tub from underwater (not the light on the controller) is blinking or turning on and of repeatedly and making a click sound similarly to a car blinker blinking on and off. What could be causing this to happen? The pump seems to be circulating and the water is heating, but the light is turning itself on and off.

SOURCE: Blinkers still have issues after replacing relay

I replaced the hazard switch relay, still no good, and replaced all the bulbs

SOURCE: QCA Opal hot tub display reading OH.

The tub experienced an overheat situation. This may be due to leaving the t stat turned all the way up and not monitoring or the hi-limit sensor is defective. The hi-limit sensor will shut down the heating cicuit if temp gets above 105 D optimally.the fact that the heater light is on is a good sign that things are working at this point.Whether or not a suitable temp(100-103 D) will be arrived at is to be seen. If spa heat kicks off before set temp is reached then replace hi-limit sensor.

SOURCE: "Jacuzzi j-400 series" hot tub- F1 code flashes on control panel

There are two things you can check, there is a tranformer that plugs into the main circuit board(usually a four wire plug). Unplug and check pins for good connection and then reconnect There are usually one or two fuses inside the control box mounted on or near the circuit board. Turn off power to spa and pull fuses and check continunity. This is a good start.

SOURCE: I have a 2004 great lakes hot tub with a balboa

check to see that the flow switch is working properly, it may not have enough flow on low speed to allow the heater to turn on. Make sure your filter/s is/are clean. If you have a pressure switch instead of a flow switch, it may need to be adjusted or replaced.

SOURCE: Hydro-Quip pack in my Hydro-Spa hot tub no heat.

Hi,
3 Flashing dots (display) - Water flow problem check for closed valves, dirty filters, water level, pump/wet end operation/defective pressure switch.
If your spa has been off for a while its likely something is blocking the lines.
Flashing dots & Lit light on display - Hi-limit trip, reset power to clear.