Rhylly

Not noticed any. It's always been a good little runner with clean exhaust and no smells.

Thanks for that. Trying to follow wires that go here, there and everywhere can be a nightmare - much easier if you know where to look. I wasn't sure if the ambient temperature sensor had any bearing on the problem but I can't see how.

Car is a 2001 model.

Mk1 Fabia 1.9tdi. Perhaps I should have also mentioned that I plugged in an OBD reader which showed no faults.

Hope someone can help. Problem starting the car. The glow plugs are not heating up. I have checked the relay which works fine. I disconnected the temperature sensor and connected a voltmeter between a glow plug terminal and earth. When I switched on the ignition I had 12.5 volts for approx. 20 seconds and the glow plug light came on too. Voltage went to zero and glow plug light went off as they should. I checked the sensor terminals and had 0v on one and 5v on the other (I believe this is a reference voltage for the ECU which changes dependent upon the resistance of the sensor). This strikes me that the circuit is working normally without the sensor. When I connected the sensor back up the glow plug light was on for about a second and the voltage was almost zero. I fitted a new sensor and exactly the same thing happened. I've tried finding a circuit diagram without success. Any ideas? I did think that there my be a short somewhere but my understanding is that the circuit appears to work fine and that the sensor simply alters the resistance in the circuit dependent upon the coolant temperature (cold = high resistance, hot = low resistance). Am I wrong? Any help appreciated.