270cdi Heater plugs.........

[RedD]

My heater plug warning light is staying on (ML270), it stays on until you stop and re-start, then after you have re-started it goes out after about 20 seconds and stays out for the rest of the day.

This morning I changed all the heater plugs and the timer/relay, started it up........... no better

Any ideas would be appreciated.

 

[psmart]

The light coming on when cold and staying on, then coming on for 20 seconds after a warm re-start is the same problem I encountered.

You've replaced the glowplugs and the relay (the one, lh inside the protected cover where the ESP and ECU are located), but they could still be at fault.

The old Relay you took out, open it up and look at the copper links which come downwards from the large connecter onto the circuit board. There should be 2 copper links per pin. Has any of these melted? If so, then you have a short circuit on the wire running from the connector to the glow plug (potentially). If you disconnect the large connector from the new relay and measure the resistance between each pin and earth (vehicle body), it should be no less the 0.5-1.0 ohms. If it is, then you still have a short circuit and your new relay is potentially knackered. If all pins are showing a resistance in the range 0.5-1.0 ohms, then the problem could be 12V getting to the relay. Measure the voltage between the vehicle body and the positive 12V connector on the relay (large singular circular pin), which should be 12-14.4V when ignition is on. If it isnt, then check the connection back to the fuse box and battery, check the fuse! If all is ok, then suspect the 3 pin connector which interlinks the ECU and the Relay. I dont have the info on these pins, so cant really suggest how to verify electrical connectivity, plus it is possible that the ECU has a fault! A quick check is to verify that earth is getting to the Relay, this is done by measuring the resistance between the black lead on the 3 pin connector and vehicle body, which should be 0ohms or thereabouts.

 

[panason1c]

Hope you post an update when you solve the problem. (-:

 

[RedD]

Booked in to local independant on Friday, so hopefully find out more then.