What he doesnt know is if the problem is the relay or the timer circuit that energizes the coil of the relay.. He know if he manually activates the relay armature with his finger the glow plugs then energize, produce heat and the tractor starts well. What he doesnt know is the relay inoperative because the coil of the relay is not energized by the timer circuitry or is it because the relay coil is open. If he understood what a relay was, and how it operated he could easily make those tests with a simple volt ohm meter. For instance he could measure for the presence of voltage on the coil of the relay by placing his leads across the coil while the timer circuit was energized by operating the key switch from the off to the on/glow position. But he does not know how to identify the coil connections of the relay. In the absence of voltage on the relay coil, there is no magnetic field generated in the coil to pull the armature of the relay over to make the contacts connect to allow the flow of the high current to the glow plugs. In any case we know the high current contacts of the relay are operational as well as its source of voltage at high current to operate the glow plugs. The only question is whether there is voltage on the coil of the relay or not. Only the Original poster can answer that, and he will have to figure it out for himself. With detailed high resolution photographs perhaps we could assist him with that diagnostic. I am willing to try.
James K0UA
