Why Does the Sauna Click and the Lights Flash?

Most infrared saunas use a control panel connected to a power control box. Inside the power box, the circuit board controls relays that turn the heater panels on and off. These relays are responsible for sending power to the infrared heaters.

After many years of use, the internal circuit board may begin to age. Common failure points include:

When the relay cannot stay engaged, it may repeatedly click on and off. At the same time, the lights may flicker or flash because the control board is no longer providing stable power.

This is why the sauna may appear to turn on, but it cannot heat normally or operate consistently.

Understanding the Control System in an Infrared Sauna

To diagnose this type of problem correctly, it helps to understand how a typical infrared sauna is controlled.

Most infrared sauna electrical systems include:

• Control panel: The user interface for power, temperature, timer, lights, and other functions.
• Power control box: The main electrical control center, usually located on the top or rear of the sauna.
• Control board or power board: The circuit board inside the power box that receives commands and controls the outputs.
• Relays: Electrical switches that turn heater circuits on and off.
• Heater panels: The carbon, ceramic, or mica infrared heaters that produce heat.
• Temperature sensor: The sensor that reports cabin temperature back to the controller.
• Low-voltage accessories: Lights, control panel circuits, audio, and other small accessories.

The control panel is only the operating interface. The power control box is the part that actually distributes power and controls the heater outputs. For that reason, when the entire sauna clicks, flashes, resets, or behaves erratically, the problem is often inside the power control box rather than in one individual heater panel.

Is This a Heater Panel Problem?

In most cases, no.

If the sauna is clicking and the lights are flashing, the problem is usually before the heater panels, not inside the heater panels. A failed heater panel normally causes one heating zone or one panel to stop producing heat. It usually does not cause the whole sauna to click, flash, reset, or behave unstable.

Why Fuses and Wiring May Still Look Good

Many customers first check the fuses, connectors, and visible wiring. This is the correct first step. However, even if all fuses and wiring look good, the internal circuit board can still be failing.

A fuse only tells you whether a circuit has been overloaded or opened. It does not confirm that the power board is sending stable voltage to the relays, display, lights, and heater outputs.

This is why an older infrared sauna may pass a basic visual inspection but still fail during heating.

Common Symptoms of an Aging Sauna Control Board

A failing control board or power box may cause:

For older SaunaGen, Health Mate, JNH, Dynamic, Sunlighten, and other infrared sauna brands, these symptoms are very common after years of use.

How to Troubleshoot the Problem

1. Confirm the Input Voltage

First confirm whether the sauna is designed for 120V or 240V power. The input voltage must match the original sauna specification. Incorrect voltage can damage the control board, cause relay instability, or prevent the sauna from heating correctly.

Check the outlet, breaker, plug, and power cord. Avoid using undersized extension cords with infrared saunas, because voltage drop under load can also create unstable operation.

2. Inspect the Power Control Box

After disconnecting power, open the power control box and look for visible signs of damage, including:

If any of these signs are present, the power board or control box is very likely damaged.

3. Check Whether the Clicking Comes From the Relay

A single click when heating starts or stops is normal. Repeated clicking is not normal.

Repeated clicking usually means the relay is rapidly engaging and disengaging. This is often called relay chatter. Relay chatter can be caused by unstable low-voltage power, a weak relay driver circuit, aging board components, or a damaged relay.

4. Watch the Lights and Control Panel

If the lights flash at the same time the relay clicks, this is an important diagnostic clue. It suggests the control board’s low-voltage supply may be unstable. The control panel, lights, and relay driver may all depend on the same low-voltage circuit.

In this condition, replacing a heater panel usually will not solve the problem.

5. Cross-Test the Heater Panels

If only one heater panel is not heating, move that heater panel to a known working heater output and test it carefully.

• If the heater works on another output, the heater is likely good and the original output or control board is the issue.
• If the heater still does not work on a known working output, the heater panel itself may be failed.
• If multiple heaters fail together while the lights flash and the relay clicks, the control system is more likely the problem.

Can You Replace Only the Original Circuit Board?

In most cases, replacing only one original circuit board is not practical.

Many older infrared sauna manufacturers no longer sell original replacement boards. Even when a used board can be found, compatibility is not guaranteed. The control panel, power board, wiring harness, temperature sensor, lighting circuit, and heater outputs are usually designed to work as one matched system.

Replacing only one board may create communication problems or wiring mismatch issues.

For this reason, the most reliable repair solution is usually to replace the control panel and power control box together as a matched universal repair kit.

Recommended Repair Solution

For this type of failure, we usually recommend replacing the old control system with a universal infrared sauna control panel kit.

A matched repair kit normally includes:

This allows the sauna to be upgraded with a stable, modern control system instead of trying to repair an aging original board.

What Photos Are Needed Before Choosing the Correct Kit?

Before selecting a replacement kit, we usually ask customers to send photos of:

1. The existing control panel
2. The power control box, usually located on top of the sauna
3. The wiring terminals and heater output connections
4. The sauna model/specification label
5. The inside of the sauna showing the heater layout
6. The voltage and total wattage information, if available

These photos help confirm the correct voltage, wattage, number of heater zones, and wiring layout.