Hi, having an issue with my 2007 Cmax 1.8 TDCI where the Glow plug light stays on for 15 seconds every start.
Light is constant, not flashing and car isn't going into in limp mode.
Car doesn't struggle to start and runs OK (but not perfect, seems a quite flat on acceleration - read on)
Until the glow plug light goes out on the dash, the electric windows and radio dont work and the dials(speedo/revs/fuel/temp) all sit at 0 but as soon as the light goes out, they jump to their correct locations and the windows/radio start working

Only had the car about 6 weeks, hooked a reader up to it (delphi autodoc) and came back with only 1 fault P0380 - DTC Glow Plug/Heater Circuit "A" Malfunction. Cleared it a few times but always got this same single fault back.
Car had a load of paperwork and it seemed to be still using the original glowplugs, so grabbed a set and replaced all of them.
On testing the old plugs (resistance and battery method), all 4 were dead, so good job we changed them anyway,

Cleared the fault code after the new plugs went in, started it up and the glow plug light is still staying on for 15 seconds every time but now we're getting a different fault code: P0299 Turbocharger/Supercharger A Underboost
This probably explains the sluggish acceleration and going to look at that next, its been suggested checking for a split vacuum hose might the best place to start.

Could the light being on for 15 seconds be a glow plug relay problem, if so, should i be getting a fault code for that as well? If the relay's not working could it just keep the circuit open all the time every start? Might explain the burnt out plugs?

 

So an update

Checked the relay and any fuses with the glow plug icon on the fusebox lid and all are working.
Tried starting the car up missing a fuse or the relay and no change, the car started just fine and the glowplug light stays on for 15 seconds and the dials wont function until it goes off.
Except on one of the startups when the light went off after a couple of seconds and the dials started moving, but only for a second before the dials froze in place.
I then realised I had hold of the key still and I turned it ever so slightly clockwise, as if I was going to start the car, and the dash dials and lights changed again.
Seems like there is a bad connection in the ignition barrell that's maybe causing this issue and nothing to do with the plugs at all!

Now does anyone know anything about ignitions......