How would I test the solonoid for my glow plugs on a 2003 F250 with the 7.3 diesel? Truck is stating hard, need to crank over at least twice as often as I used to. Had trouble a year ago and had one replaced under warranty but am out of warranty and am unhapppy with dealer response.

There is battery power on one side of soliniod, when the key turned on, the solinoid gets its signal on the small wire which activates solinoid and sends battery power out the other side of solinoid, if there is no power on the smal wire when the key is turned on a possible glow plug modual or a fuse could be the problem.

Glowplug relay for 2002 ford f-250