Best Glow Plug Relay For 7.3 Powerstroke: Our Top 6 Picks

Glow plugs inside a 7.3 Powerstroke engine help ignite the fuel and air mixture, which in turn powers the engine. But for the glow plugs to work, they need electric power. And this is where glow plugs relay comes in handy.

The glow plug relay sends power to the glow plugs to heat up. Unfortunately, glow plug relays are prone to wear and tear like any other component inside the engine. Worn-out relays will lead to engine slow starts, especially in cold temperatures.

So if your engine relay is worn out, you will need to buy a new one. However, not all glow plugs are suited for the older 7.3 Powerstroke. So, which is the best glow plug relay for 7.3 Powerstroke? Find out below.

Top on our list is the White Rodgers 586-902/586-105111 DC Power Contactor Solenoid, SPST-NO,... * (#ad) it works well in extreme cold conditions and is designed to directly replace the OEM relay. It is also easy to install and has an amp rating of 200 amps.

The second is the Dorman 904-194 Diesel Glow Plug Relay Compatible with Select Ford... * (#ad) it is built from aluminum, making it one of the more durable options on the market. It is also easy to install is a better fit than the White Rodgers though it does not have the same amp rating

Our Top 6 Best Glow Plug Relay For 7.3 Powerstroke: A Quick View

Please note that Prices and Availability Are Subject To Change

What Are The 7.3 Bad Glow Plug Relay Symptoms?

Before we delve into which is the best glow plug relay for the 7.3 Powerstroke, let’s first discuss the symptoms of a bad glow plug control module. 

  • Slow start: if you notice that your engine is taking longer than usual to start, especially on cold mornings, a faulty glow plug relay may be the cause. In most cases, you will also notice white smoke until the engine starts.
  • Rough idling: rough idling can be another sign of bad glow plug relays. You may also notice hesitation with the engine after the car starts.
  • Check engine light on: When the check engine light is on, it may be because of a faulty relay. However, this can also be caused by other issues, so it is wise to manually check the relay.

The faulty starts may also be caused by a bad glow plug on your 7.3 Powerstroke. So it will be wise to check the glow plugs and examine properly if you notice any misfire, poor acceleration, or difficulty to start the vehicle. If you find the reason behind the poor starts is by glow plug itself replace with one of these best glow plugs for 7.3 Powerstroke. We wrote a detailed guideline on how to check the glow plugs on your 7.3 Powerstroke. Hope you will find the guide useful too.

How To Test Glow Plugs Relay Easily

If you notice any of the above symptoms, the next cause of action is to test the glow plug relay to verify that it is indeed the cause of the problem. To test the relay, you will require a voltmeter.

Firstly, you will have to locate the relay. The 7.3 Powerstroke glow plug relay is located on the passenger side engine valve cover. You will find it behind the fuel filter housing and have brown and yellow wires attached.

Take the voltmeter’s black wire and ground it on a clean piece of metal to serve as the ground. Then take the red wire from the voltmeter and attach it to the black wire connection on the left side of the relay.

It should display a volt of 12.5 volts, indicating an electric current flowing into the relay. Ensure the ignition is off. Next, attach the red wire to the attachment on the right side of the relay, where the brown and yellow wire connect. 

The reading should be 0.00 volts since the ignition is off. Next, switch on the vehicle’s ignition and retest the wire attachment on the right. If the relay is functioning optimally, you should get a 12.5 volt reading on the voltmeter. If you do not, then the relay is worn out.

Why Does The Glow Plug Relay Click?

Sometimes you will hear a clicking sound from the glow plug relay. This is usually caused by the relay re-cycling power to the glow plugs. Check your battery and charging system as well as connections. 

7.3 Powerstroke Glow Plug Relay Location and Wiring Diagram

So what is the 7.3 Powerstroke glow plug relay location? The plug relay is located at the passenger side engine cover. Usually behind the fuel filter housing. The relay will have brown and yellow wires attached to it. Below is a 7.3 Powerstroke glow plug relay wiring diagram.

7.3 powerstroke glow plug relay wiring diagram
7.3 powerstroke glow plug relay wiring diagram and location
Ref: 3

Best 7.3 Glow Plug Relay Reviews


First up on our list is the White Rodgers 586-902 contactor. We replaced a 99 F250 7.3 stock relay with this one. And while it does not come with a wiring diagram, the installation was pretty straightforward.

It was tight, with the solenoid mounting at a 45-degree angle once in place. We recommend using an open-end wrench to tighten the mounting bolts. In terms of overall quality, the mounting brackets and faceplates are thick.

As for what it is built to do, the engine will start with no problems, even in freezing weather. In addition, it makes for a great 7.3 Powerstroke glow plug relay upgrade on the default relay. 

Rodgers starts the engine quicker compared to the default relay the 99 F250 comes with, which is a great sign. Also, you can find a white Rodgers 586-902 wiring diagram online.

Dorman 904-194 Diesel Glow Plug Relay

The Dorman 904-194 Diesel Glow plug relay is designed to directly replace the 7.3 Powerstroke relay on select Ford models. It is designed to fit the F250, F350, and F250 super-duty line of trucks.

Built from solid aluminum, it is a durable relay that should last. Since it is designed to be a direct replacement for the 7.3 default relay, it is easy to install. It will take a few minutes to install, and the fit is excellent.

It also works well, even in cold climates. However, it does take about 4 to 5 turns of the key for it to actuate. This was disappointing, but it does get the engine started even in extremely cold weather.

QWORK Glow Plug Relay Compatible w/ 7.3L Diesel

Another glow plug relay designed to directly fit with 7.3 Powerstroke is the Q work Glow plug relay. Like most other glow plug relays, it is made from metal and plastic parts.

Thanks to its plug-and-play design, it fits well and is easy to install since it is designed as a replacement. It also works well, even in extreme cold. 

We noticed a minor issue with the top terminals in that they would have been better if they were placed a little further from the divide, for its price though it is well worth i.

Motorcraft DY861 Glow Plug Switch

The Motorcraft DY861 glow plug relay is smaller than the White Rodgers. This means it offers a better fit. And while it does not provide the 200 amps contact rating of the White Rodgers, it is still a great relay to get for its price.

It is designed to match the quality of OEM glow plug relays. As such, it performed relatively well in cold weather. The relay is also abrasion-resistant as well as environmental corrosion. Overall, given its price, it does offer good value for money.

The only complaint we had about this relay is that it does not come with nuts and washers for the terminals included. 

Automotive Authority 12V Solenoid

With a 200 amp rating, the Automotive authority 12v solenoid is another excellent option. Similar to the white Rodgers, it is pretty big compared to the OEM relay. And this means you can expect a tight fit when installing it.

When installed, the relay works regardless of the weather. So if you have issues with your 7.3 Powerstroke Ford truck, this will be an instant upgrade. It works much better than the old relay we removed from a 2002 F250.

Because of its size may prove to be challenging to install for some, but it is not all that difficult. And considering its price and what it offers, it is well worth it.

XtremeAmazing New Diesel Glow Plug Relay

The Xtreme Amazing new diesel glow relay is one of the cheapest on the market. And while its price may concern some, it is an excellent alternative to pricier options. It will fit 7.3 Powerstroke from 1995 to 2003. 

One of the best things about this glow plug relay is how easy it is to install. It also fits well and seems to directly replace the OEM glow plug relay. And despite its price, it works well enough.

Care needs to be taken when tightening the threads, though. However, this can be considered the price to pay for such a cheap relay. All in all, for the price, it works well enough.

Frequently Asked Questions

How to Test Glow Plugs on a 7.3 Powerstroke With a Test Light

If you do not have a voltmeter available, you can use a test light to inspect your relay. To do this, connect the test light to the two little terminals and turn on the ignition. The test light should be light to indicate there is power flowing into the plug relay. Next, connect the test light clip to the engine ground. Then with the ignition turned off, connect the test light to each of the big terminals on the relay. One of the terminals will cause the test to light up. Finally, turn the ignition on again, which will cause the opposite big terminal to get hot. If it does not get hot, then the relay may be faulty.

How Do I Check My Glow Plugs Using a Digital Multimeter?

You can also use a digital multimeter to test the glow plug relay. First, take a digital multimeter and set it to volts. Then attach the black test lead to a clean piece of metal to act as the earth wire. Once this is done, connect the red lead to the left side wire of the relay. You should get a 12 volt or 12.6-volt reading meaning the relay receives power from the battery. Test the right side wire attachment, and you should get 0 volts reading with the ignition turned off. Turn on the ignition and test the right wire attachment of the relay, and you should now get a reading of 12 volts or 12.5 volts. If not, it may be a sign of a faulty glow plug relay.

How long do glow plug relays last?

On average, the glow plug relay will last for up to 60,000 miles. The relay may last longer or shorter depending on its quality and the oil temperature.

Best Glow Plug Relay For 7.3 Powerstroke Buying Guide

So what should you consider when searching for the best 2000 7.3 glow plug relay. There are a couple of things to consider, the main ones being.

Compatibility and fit

Not all glow plug relays will fit into the 7.3 Powerstroke. Thus, when searching for a glow plug relay, check if it is compatible with the 7.3. Furthermore, the fit is another thing worth considering. Some relays, such as the White Rodgers, tend to be big and have a tight fit. Again, this is something to take note of when shopping for a relay.

The construction

The glow plug relay needs to be durable so that you are not buying a new relay every other month. Most good-quality relays are made from metals such as aluminum and steel. Some are made from a combination of metal and plastics and tend to be cheaper. 

Current regulation

One of the primary functions of the glow plug relay is to regulate the internal electrical conductivity. Thus its ability to perform this function is key. The best glow plug relay for 7.3 Powerstroke will typically have an amp rating of 200 amps.

Ease of installation

How easy a glow plug relay is to install also matters. Some relays are easier to install and come with a wiring diagram to help you know how to install. Not all relays come with a wiring diagram, though. Thus it is essential to check if a wiring diagram is included. However, it can still be easy to install with lots of tutorials online if not included.


The glow plug relay is a small but immensely important component. Without it, your 7.3 Powerstroke truck will have a hard time starting. There are plenty of options available on the market. The best glow plug relay for 7.3 Powerstroke is one designed for the 7.3 engine, which will improve your vehicle’s engine startup time. 

Last Updated on June 28, 2024 by Rifen

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