Mercedes-Benz W164 glow plug and glow plug relay faults
ML 320 CDI420 CDI
Mercedes-Benz W164 glow light is on or glow plugs don't work, what is wrong?
The cause can be a fault in the glow relay, i.e. the glow plug control unit, even if the glow plugs have been replaced. A faulty glow plug can also damage the control unit and vice versa, so when one is replaced, check the other as well.
Can a burnt conductor in the Mercedes-Benz W164 glow relay be repaired?
First check that the aluminium wires running from the circuit board to the connector are intact. A burnt or broken wire is replaced with a new wire by soldering, and the surface of the circuit board is filed clean first so the solder adheres.
Does the Mercedes-Benz W164 glow relay need programming after replacement?
No programming is needed. The fault memory can be cleared with a diagnostic tool if necessary, but clearing is not required.
Which socket fits the tight recess around a Mercedes-Benz W164 OM642 glow plug?
A standard 8 mm long 1/4 inch drive socket fits the recess around the glow plug, even though the space first looks too tight.
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