RonMar
Elite Member
Blows when holding in the H position... I agree, it sounds as if one of your glow plugs is "running away" or pulling more current as it warms up. They are supposed to pull less current as they warm. As Greg suggests, disconnect the green wire from the glowplug bussbar(make sure the wire end is not touching anything) located along the left side of the valve cover. If it still blows, you have a problem in the harness or key switch.
If the fuse survives this test, You can reconnect that wire to the glowplugs one at a time(remove the bussbar) and see how much electrical current each glowplug is pulling in the "H" position using the installed AMP gauge on the instrunment panel. You are looking for the one that pulls more current than the others. Do not apply power to the glow plugs for more than about 15 seconds.
Normal operation for my tractor in the Heat position is about a 25+ Amp current draw indication on the amp gauge. As I count to 15, that amp draw drops closer to 20A. That is for 3 glowplugs in parallel, so each carries about 1/3 of the current. For a single plug, you should see about 8-9A of current initially, dropping to around 6-7A after about 15 seconds... Test each individually and see if you have an oddball...
If the fuse survives this test, You can reconnect that wire to the glowplugs one at a time(remove the bussbar) and see how much electrical current each glowplug is pulling in the "H" position using the installed AMP gauge on the instrunment panel. You are looking for the one that pulls more current than the others. Do not apply power to the glow plugs for more than about 15 seconds.
Normal operation for my tractor in the Heat position is about a 25+ Amp current draw indication on the amp gauge. As I count to 15, that amp draw drops closer to 20A. That is for 3 glowplugs in parallel, so each carries about 1/3 of the current. For a single plug, you should see about 8-9A of current initially, dropping to around 6-7A after about 15 seconds... Test each individually and see if you have an oddball...