Freelander 1 Glow plug forced activation

Is there a way to activate the glow plugs also at warmer weather?
I noticed that in winter, the glow plug lamp on the dashboard turns on, i wait until its off and my td4 starts easily.

However in warmer seasons the glow. Plug lamp doesnt turn on and its more difficult to start the engine.

What could cause this? Could be somehow forcibly activate the glowplugs when warm already?
Thanks

The ECM puts the glow plugs on a lot more than it puts the light on. The light only comes on if you need to wait for the combustion chamber to pre-heat for a cold start. However the ECM puts the plugs on even if they're not needed for starting, as they also improve combustion.

And leaves them on for a while after starting too. Stick a voltmeter on one..it is interesting.