Mercedes W210 E320 E270 CDi glowplug relay repair.

(This is also relavent for W211 E270CDi and E320CDi cars)


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If your glowplug light stays on after the warm up phase of running your engine.  

More than likely you have a failed glowplug - these can be tested by using a 12v test light to ground thru them.  With a multimeter most good glowplugs measure less than 1.0 Ohm resistance.

Bosch or Beru plugs have a lower internal resistance than NGK or genuine Merc plugs.  So thus relay lifespans are higher using lower resistance plugs.

So if you have checked your glowplugs and they work - more than likely, the power hold relay has failed (glowplug relay).  Or a glowplug has failed and has damaged the fused lnk in the relay.

 W210 diagnostic socket.

  Sykes code reader with 16pin to Merc plug adapter.

  Glowplug fault - but glow plug was OK.

  Glowplug relay fault - not clear is it?

  Glowplug relay - nearside inner wing,  availiable from Merc specialists for 120 + VAT.  Mercedes dealers want 160 + VAT.

  Cut sealant from face seal - prise away outer plastic case.

  To reveal - 30 amp fuse link to NO1 glowplug has failed (same as faultcode recoreded).

   Solder in a short length of 30 amp fuse wire.

  Make sure you solder joints are big enough to handle a 30amp load at 12volts (just make them huge and ugly).

  Resealed with black RTV but you could use "any silicone sealant".



Fixed - if you can't do it - bring the relay (or car) to my workshop at PE301FB - I will charge you 60 for the job!  (far cheaper than a new relay!).

Mercedes dealer will want 160 + vat for the relay - and "god knows how much labour?" - to diagnose it and fit it at 100 an hour plus VAT.



(date information written)