L245DT wont start

Had just finished mowing and stopped to blow the grass off. Tractor would not restart. When the key was turned to ON, no lights lit on the instrument panel. The continuity of the clutch pedal safety switch checked OK. All fuses on the instrument panel checked OK. The battery tested OK. 12 volts present at the positive battery cable connected to the starter. 12 volts present at the key switch. Less than 1 volt present at red/white wire on key switch when the key was turned to ON. Jumped red and red/white wires on key switch terminals - nothing happened.

Thanks! Already tried that and nothing happened. Battery checked OK. Battery terminals clean. Will try jumper cable to bypass positive cable from battery to starter. Positive cable looks OK, but is 35 years old.

Thanks! My brother had battery tested at local parts store (didn't say which one). I'll try a few more things asap and will repost when the true problem is determined.

This tractor actually belongs to my brother. I just get to work on it. When he originally told me of the problem, I evidently misunderstood. I thought he said he stopped the tractor to clean it off, and then it wouldn't restart. Today, he said it stopped running by itself just as he was getting ready to shut it off. He then said it wouldn't restart. He said it acted like a dead battery. This may be a different problem entirely. Anyway, let me list everything that has been checked so far: 1) battery was tested (at Advance Auto) and showed about 12.5 volts and 540 cranking amps, 2) jumped battery post on starter to post on solenoid and nothing happened, 3) battery terminals and cable ends on battery were cleaned, 4) ground cable connection was cleaned, 5) battery cable/wire connections at starter were cleaned, 6) connected jumper cable from positive battery terminal to terminal on starter - WHEN THIS WAS DONE THE INDICATOR LIGHTS ON THE INSTRUMENT PANEL THEN LIT WHEN THE KEY SWITCH WAS TURNED TO "ON". We then tried to start the tractor, but it cranked VERY slowly. The engine would not crank fast enough to start. There is definitely a problem with the positive battery cable. Then used my truck to try to jump start the tractor. Connected positive jumper cable directly to the starter and grounded the negative cable to the tractor frame. This bypassed the tractor battery and battery cables. The indicator lights lit when the key was turned ON, but the engine would still not crank fast enough to start. I then removed the starter from the engine and connected the jumper cables to it. When the key was turned ON, the starter seemed to spin freely with the pinion gear extending as it should. The starter was reinstalled, the jumper cables were connected again (to starter and ground), but the engine STILL cranked very slowly. The battery will be tested again, we'll get a new positive cable, but the fact the tractor stopped running on it's own is NOT a good sign.

Pulling out decompression knob made no difference - still cranked slow. Will check coolant and oil.

The (starting) problem turned out to be a bad cable from the battery to the starter. A set of jumper cables used in the trouble shooting process was found to be not much better than the battery cable. That's why my truck wouldn't start the tractor either. I just ASSUMED the jumper cables were OK. Everyone (except me, I guess) knows what happens when you assume something. Anyway, the positive battery cable was replaced and the tractor started fine. No oil was found in the coolant and no coolant was found in the oil. Why the tractor stopped by itself is still a mystery, but it seems to start and run normally now. Thanks guys for all your input in helping to figure this one out.