PCM Relay Clicking: How to Test and Solve the Problem?

You notice a constant clicking sound coming from your car. It’s particularly coming from where the PCM relay is situated. 

So, what should you do to solve the PCM relay clicking problem?

To solve the PCM relay clicking problem, first, you have to diagnose the cause. It happens due to a faulty wiring system or when the battery is dead. So, replace the battery or charge it fully (if it lacks charge). Then, arrange all the battery connectors and wires properly. In case the PCM relay is problematic, replace it. 

I’ve explained both the diagnosis process and replacement process in detail below. Keep reading to learn more about it. 

What Does it Mean When a PCM Relay is Clicking?

When a PCM relay is clicking, it means there’s a problem with the voltage supply or wiring system. Usually, the PCM relay clicks in two scenarios. 

Here’s an explanation of why the PCM relay makes clicking sounds in both of the scenarios.

Rundown Battery:

Rundown Battery
Source: Underhood Service

The PCM clicks while having a rundown battery because the voltage is very low. When you activate the PCM, it sends signals to the electrical circuit. The battery is supposed to take the load. 

But when you have a dead or rundown battery, the battery can’t handle the excessive load. As a result, the voltage drops and so the PCM relay also stops working. 

Again, when the voltage rises, the PCM works taking the power supply and load. Eventually, the voltage drops and it becomes a cycle. The constant voltage rise and drop then become the cause of clicking sounds.

Engine is Off

The PCM relay also clicks when the engine operations and ignition switch are off. In this case, you’ll notice that the loud clicking noise comes from the upper intake manifold and the PCM relay.

It happens when there’s an issue with the wiring system. If you have a faulty wiring system attached, or if any of the connectors are broken and damaged, you’ll hear the constant clicking noise. 

Now, remember that the PCM relay clicking noise problems have nothing to do with the grinding noise problem in your F150.  

Is a PCM Relay Good if it Clicks?

Is a PCM Relay Good
Source: Mechanic Base

No, a PCM relay isn’t good if it clicks. A noisy PCM relay indicates that the relay has some internal problems. The possible problems are: voltage supply issue, drained out battery, starter solenoid issues, PCM relay wiring issues, and damaged starter motor. 

So, whenever you’ll notice that the PCM relay is making a clicking sound, you must diagnose the relay, battery, and starter motor if there are any issues.

How Do You Know if a PCM Relay is Damaged?

The PCM relay clicking sound is an indication that there might be a problem in the PCM relay. But there are other visible symptoms that indicate a damaged PCM relay. 

Here are the ways to test if the PCM relay is damaged or not.

  • The blinkers are not working.
  • The air conditioning is not working properly.
  • The fuse has blown due to system overload. 
  • The dashboard is showing Code P0685.

Now, you can test the PCM relay even if you don’t see any of the mentioned symptoms. In this case, you have to manually test the relay.  

How to Test a PCM Relay?

You should test a PCM relay by following the steps below.

  • First, you have to locate the PCM relay. You’ll find it under the dashboard on the right side of the steering column. In the Ford F150, the PCM relay is located in the passenger-side steering column. 
  • As soon as you find the PCM relay, remove the relay from the fuse box. 
  • After that, take a multimeter and set it to Ohms. This will help to measure the DC voltage. Activate the cab by switching it on. 
  • Next, grab the multimeter and check the relay plugs if they show 12 volts of power at the 85 positions. 

If you don’t see this voltage appearing on the screen, this means the fuse has blown. But if you notice the current flow to the relay from the switch, this means the PCM relay is alright.    

You can also replace the relay with a new or working power relay and test the voltage. This will also help you to identify whether the old PCM relay has become damaged or not. 

Here, remember that you don’t have to jumpstart the replay like you jump the fuel pump relay on a Chevy truck

What to Do if the PCM Relays Clicking? 

Now, before moving to the solution. Here’s what you should do when you see the PCM relay clicking.

Step 1: Check the Wiring System

Since faulty wiring is a major cause of PCM relay clicking, you should inspect the wiring system first. You’ll find 3 relays together in the fuse box. 

The outermost and middle relay should have 5 gray wire connectors each. And the rearmost relay should have a brown 7 wire which is connected to the PGM-FI relay. 

If the wiring is not in proper order, you have to rearrange the connectors. But if any of the wires or connectors are damaged, replace them immediately. 

Step 2: Inspect the Battery

Inspect the Battery
Source: CarTreatments.com

After checking the wiring, you should inspect the battery too. Take a multimeter and test the battery if it is fully charged. If the multimeter reads 12.6 volts (while the engine is off) and 13.7 volts (engine running), this means the battery has no issues.

But if you notice that the multimeter is showing less voltage than the mentioned amount, this means the battery lacks charge. 

In this case, you should charge the battery completely and test it again. If the less-voltage issue appears again, this means your battery is drained out. You need to replace the battery.

Step 3: Replace the PCM Relay

Now, if you see the clicking issue reappearing even after correcting the wire connections and fixing the battery, this means the PCM relay is problematic. You need to replace it immediately.

To change the PCM relay, you have to follow the steps below.

  • First, you have to take out the passenger side cover near the foot.
  • Next, simply remove the PCM relay with your hands. Lightly dab and pull the PCM relay outwards. It’ll come off easily.
  • Then, place the PCM relay in the same slot you’ve removed the old relay from. Make sure the pins are exactly in the same position as the old relay was. Use a PCM relay wiring diagram for help if you need it. The model and pins should be identical as well.
  • After that, lightly press on the new PCM relay. The pins will nicely fit in the slot. 
  • Finally, close the cover and start the engine to see if it’s working. 

By replacing the PCM relay, it’ll stop the clicking sounds. 

Frequently Asked Questions (FAQs):

What does the PCM relay do?

The PCM relay acts as a bridge between the ECM and the battery. It’s basically a switch that minimizes the wastage of overload voltage. When the ignition key is turned on, the PCM relay starts converting the power supply from the battery to the engine.  

How many years do relays last?

Relays generally last for at least 100,000 operations. It’s actually connected to the life expectancy of mechanical operations. The number may differ based on life expectancies such as 1 million, 10 million, or 100 million operations.  

What are the common faults of relays?

The most common faults of relays are contaminated power supply and worn-out electrical components. Because of contaminated high power voltage, the relay gets damaged. Again, due to high-frequency mechanical usage, the relays get damaged or worn out quickly. 

Final Words 

Hopefully, you’re now aware of what you should do when the PCM relay is clicking. The most important part for you is to diagnose the cause of the issue carefully.

By following this article from top to bottom, hopefully, you’ll be able to get rid of the clicking issue. Best of luck!

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