Thanks PHD. I can't even find the glow plug relay, it's not in the engine bay so I will dig out the dash lower fascia panel tonight.Here is the one (Black/Red)
Many thanks PHD. I will try and find this under the dash
View attachment 553558
And the others :
do not get confused between R/B (below) and B/R(above) colours of the wires.
View attachment 553560
With a manual switch spliced in between the ECU wire and a ground, I assume this will only turn the glow plugs on when the (momentary) switch is held. Ie the glowplugs won't stay on for an extended period.