How to Test Glow Plugs – Measure the Resistance (Still Fitted to the Vehicle Video)

How to Measure the Glow Plug Resistance without Removing from Vehicle.

Testing Glow Plugs Without Removing From Vehicle

Can be a quick way to check if they’re OK. It doesn’t always produce accurate results though (if there’s poor contact, corrosion, etc). However, testing in place can still be a good indicator on the condition. I.e. Poor results – Remove the glow plugs from the vehicle and check / test again…

The brief description that follows, helps explain why your vehicle doesn’t start easily when cold, and why we need to test the glow plugs…

Petrol engines start with the assistance of a spark from a spark plug to ignite the fuel. Whereas diesel engines start using the compression of the fuel mixture. However, diesels don’t like starting when cold. Hence diesel engines are fitted with glow plugs that heat the air fuel mix to aid starting when cold.

If a diesel engine is running well and starts easily when the engine is warm, but won’t start when cold, (or takes ages to get it started when cold). It could be an issue with the glow plugs, the glow plug system (module, relay, or voltage supply). This video shows how to test glow plugs without a multimeter (test meter).


Ordering Parts (Glow Plugs, Test Meter, Tools, etc):

The following table gives examples of the test equipment, tools, etc you can buy to fix your vehicle. If you’re not sure what you need, sometime it’s worth having a look? The list below may give you an idea of what’s what’s available, what to look for and how much it costs…

Ordering Parts – Examples of What You Can Buy:

Glow Plug Prices
Item Location
United Kingdom UK   Glow Plugs
Test Equipment
Glow Plug Tools
Jumper Cables
United States USA Glow Plugs
Test Equipment
Glow Plug Tools
Jumper Cables
Australia AUS Glow Plugs
Test Equipment
Glow Plug Tools
Jumper Cables
Canada CAN Glow Plugs
Test Equipment
Glow Plug Tools
Jumper Cables
Ireland IRL Glow Plugs
Test Equipment
Glow Plug Tools
Jumper Cables
Disclosure: The links in this table are “affiliate links” This means we may garner a small commission (at no cost to you), if you choose to make a purchase.
Thank you for your support.

Other Glow Plug Videos:

How to Test Glow Plugs:

More Detailed Info:

More detailed information can be found on this page: Diesel Won’t Start When Cold – How to Fix Glow Plugs: (Opens in a new window / tab)