23/08/2026 8:38 am
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Automotive Q&A
Sprinter P0672: glow-plug resistance is normal at the plug but not at the module
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A 2016 Sprinter stores a cylinder 2 glow-plug circuit code in cold weather. Resistance measured at the plug matches the other cylinders, but from the glow-control module connector the circuit is intermittently open when the harness is moved. The plug itself is not being removed yet because of seizure risk.
Is end-to-end harness testing enough before considering the control module?
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24/08/2026 8:26 am
Yes. Compare voltage drop or a low-current continuity load from the module terminal to the plug connection while flexing the harness. Inspect the connector and terminal grip at both ends. If the conductor opens but the plug remains stable, repair the harness before evaluating module current control.
After repair, use the guided output test to compare current on all glow circuits. Avoid powering a glow plug directly unless the service procedure specifies the voltage and duration; modern plugs can be damaged quickly.
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25/08/2026 9:41 am
The cylinder 2 conductor was broken inside a bend below the intake. A sealed repair restored the same loaded reading as the other circuits. The module then delivered matching current and P0672 did not return on the next cold start.