A tech here on Appliantology encountered an issue with the LED lights in a Whirlpool side-by-side refrigerator that kept flickering in both compartments. He suspected that one of the LED boards was the culprit, but he couldn't figure out how to identify which one.

Let's take a look at these LED boards on the schematic and think about how we could troubleshoot this situation.

Looks like we've got three different LED boards -- one for the freezer compartment, and two for the refrigerator compartment.

Note that one of these boards is not like the others: the refrigerator LED board on top also converts AC power into DC.

The pinout confirms this and gives us the expected voltages:

So the AC/DC LED module converts AC to DC and then supplies DC voltage to the other modules. Here's what that circuit looks like:

Another important thing to note here: the LED boards are in series with each other. This helps us with our troubleshooting! Even though all the LEDs in the unit are flickering, this is most likely simply the result of one of the boards failing. Since they are all in series, if one fails, it will affect the others.

Now that we know how the circuit works, what test can we do to figure out which board is the bad actor?

Appliantology Brother and Master Samurai Tech Academy alumnus Kevin Anderson pointed out the simplest and most informative test you can do here: simply jump the boards one at a time and watch to see when the lights stop flickering. If the lights stop flickering once you jump a board, then you've found your culprit.

Here's how you would implement that test, first jumping the refrigerator LEDs (the jumper is shown in yellow):

Then the freezer LEDs:

And if the flickering continued during both tests, then you know the issue is with the AC/DC LED module.

There you have it -- two simple tests to identify exactly which board needs replacing! This troubleshooting strategy applies not just to this particular model -- lots of LED configurations are chained together in series like this, so this same strategy of jumping loads one at a time to identify the failed load is a good one to keep in your tool bag.

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