When I first got my 1010, I pulled the glow plugs and checked them by grounding each one on a steel trailer and applying battery charger current to them. All of them were good, but the funny thing I noticed is that for the first 10 seconds, absolutely nothing happened. Then they turned orange. So knowing that, I hit mine for 20 seconds on a normal day, but in winter, I'll go 45 seconds or so.