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

If you need parts, try... Glow Plugs - (UK) - https://ebay.us/aDgbkH Glow Plugs - (USA) - https://ebay.us/8MSxEU Test Meter (Multimeter) - (UK) - https://ebay.us/TYvuAn Multimeter (Test Meter) - (USA) - https://ebay.us/5UXl14 Glow Plug Removal Tools - (UK) - https://ebay.us/XCVgft Glow Plug Removal Tools - (USA) - https://ebay.us/FohVav Jump Leads - (UK) - https://ebay.us/4SMEtI Jumper Cables - (USA) - https://ebay.us/92CL4z Disclosure: The links above are 'affiliate links' This means we may garner a small commission (at no cost to you) if you choose to make a purchase. Thanks for your support... 😃 For more information, see: https://do-it-up.com/vehicles/engine-... There is a typo at 1:40 where it says 3m ohms, this should be 3M ohms... Other Videos: With a test meter:    • How to Test Glow Plugs From Start to Finis...   Without a test meter:    • How to Test 12v Glow Plugs From Start to F...   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).