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How to Check the Functioning of the Glow Plugs

Model: (Various brands) Various
Part: Glow plugs

There are several ways to check the proper functioning of the glow plugs, some a bit empirical but certainly effective, and others more systematic and accurate. Once you locate the glow plug socket, disconnect the respective connectors and obtain a piece of electrical wire that is not too thin and long enough to reach from the positive terminal of the battery to all the glow plugs; then position one end of the wire on the positive terminal of the battery and with the other touch the glow plug: if sparks are created, the glow plug is fine; alternatively, you can use a multimeter to measure the electrical resistance of the glow plug (the glow plugs should have a resistance varying between 0.6 and 2 ohms), or check for continuity.

Updated on 20 February 2026 by ScegliAuto

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