W210 diagnostic socket.Mercedes W210 E320 E270 CDi glowplug relay repair.
(This is also relavent for W211 E270CDi and E320CDi cars)
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.
16-09-18
(date information written)