Glow Plug Relay

[raw]

Anyone able to explain the reasons behind my GPR having failed in such a way that it is on any time when it is connected to the ignition live and the ground (i.e. whenever the blue ign live and the black ground are connected).

i have checked the signals from all the wires to it and am getting voltages that make sense from ign live, start live, warning lamp, and earth, but i don't know what the voltage from the temperature sensor should be. with the engine hot at the moment the temperature sensor signal is 0V, thought it was 11.2V when it was cold but i'm not sure.

i have checked all the internals of the relay unit, cleaned the relay contacts which are free moving and work fine (it goes on and off fine when the power is connected/disconnected), and all the solder joints on the circuit board have been reflowed despite seeming to be fine.

as far as i can tell now i'm down to the possibilities being the PCB or the temperature signal from the cylinder head temperature. some photos below of the relay unit incase anyone might be able to see anything amiss, though i somehow doubt it.







cleaned up the relay contacts with wet and dry after taking that first photo and they're now nice and shiny, but it's changed nothing at all :|

Richard