How To Test Grid Heater 5.9 Cummins? 3 Easy Steps!

Do you want to learn how to test grid heater 5.9 Cummins? To test the grid heater of a 5.9 Cummins, you will need a multimeter in the voltage setting to measure the voltage of the relays. You must place one of the probes on the battery’s positive terminal and the other on the grid heater relays. Next is to turn the key on and test the other side of the relay to see if the voltage passes through it. The relays should click, and the grid heater should whine.

Using the multimeter, you can determine if there are loose connections and if components like the relay or heating element are defective.

how to test grid heater 5.9 Cummins

The purpose of the grid heater is to prevent cold starts by warming the air charge. You should find the grid heater next to the air horn and see its connection to two relays (also known as solenoids) located around the fender well, depending on the truck model. The relays should click when the engine is started and the grid heater is heard. If the grid heater is not working, you can troubleshoot and diagnose the problem to see what needs to be fixed or replaced. To understand more about the 5.9 Cummins and its grid heater, continue reading.


What Is 5.9 Cummins?

The 5.9L Cummins is a well-known engine. The 12 and 24 valve versions have a large fan and consumer base. Even though their production stopped more than a decade ago, more Cummins trucks are than Duramax and Power Strokes. The Bosch CP3 injection pump, if the 5.9L Cummins, makes around 23,000 psi and keeps the fuel pressure around that level with its high-pressure common rail. The engine also features a fixed geometry turbo, which boosts up to 45 psi but maintains its durability.

The pros of the 5.9L Cummins compared to its 6.7L counterpart are the presence of a 325hp and 610lbft stock, the reliability of its fixed geometry turbo, and its emissions that are limited to only those coming from the catalytic converter, and its lower cylinder pressure and increased sealing area. The disadvantages of the 5.9L Cummins over the 6.9L version include decreased displacement, lower torque, laggier turbo, and smaller injection lines and fuel rail. To learn how to test grid heater 5.9, Cummins keeps on scrolling.


Steps To Test Grid Heater 5.9 Cummins

Now that you know all about the 5.9L Cummins engine, we can proceed to the step-by-step procedure on how to test its grid heater. These are pretty simple to follow, and you can follow the steps to test the grid heater’s functionality. This step can also help you identify the problem of the grid heater if any. Ensure that you have the required tools and that some protective gloves won’t hurt.  So, how to test grid heater 5.9 Cummins? The steps are elaborated on below.


Step #1. Tell-tale signs of defect

If you decide to test the grid heater on your 5.9L Cummins, you probably think it is not working like it is supposed to, or you want to make sure that everything’s all good under the hood. The fastest way to tell that the grid heater is not working is when you do not hear the click of the relays when you start the engine. You might hear the relays click, but if the grid heaters don’t begin and you don’t hear its whine when it starts, there is probably something wrong with the grid heater.  


Step #2. Multimeter testing

To trace where the problem lies, you need to grab a multimeter tester and put it on its voltage setting. Next, locate the relays and positive battery terminal under the hood. Measure the voltage by placing one probe on the battery terminal and the other on the relay terminals. There should be no current passing through the relay with the engine off. Turn on the machine. If the current fails to pass through the relay, the problem is between the relays and the grid heater. Check for damages to the fusible link or loose connections. You may also be interested to know how to use a multimeter.


Step #3. Component replacement

Once you have identified the components or parts that need replacing, you can swap them out yourself or have someone do it if you feel intimidated. If you have the experience, we recommend swapping the old part with the new one yourself. Ensure that you wear gloves and other required protective gear to prevent potential dangers to your safety. Are you aware of how to use a multimeter?


It’s A Wrap!

Congratulations on reaching the end. We want to thank you for the time and effort you have spent reading. Hopefully, you have learned a lot about how to test grid heater 5.9 Cummins. Now you have a better idea of what the 5.9 Cummins is and what to do if you want to see if its grid heater is working correctly. If you are not confident doing the testing yourself, you can always ask a friend who knows this stuff or leave things to a professional. Remember to keep safe and arm yourself with knowledge before diving into something new. Until next time! Don’t hesitate to know these things too; read about why car heater is not working and car overheats when the heater is on.

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