electric starter/starting issues

[010175]

1998 suburban, owned it for 15 years, 220,000 miles, new battery, starter last year, cleaned connections by disassembling all parts at battery! The bolt out, the round lead thick washer out, ect. The problem is when I turn the key at times it acts like a dead battery. Jump starting works all the time. If I go from off to start with the key sometimes it will not turn the starter. If i go from off to on, wait 20 sec, then start, it will start. Is there a starter relay somewhere not on the starter that is going bad? What is the chance it the ignition switch? I know its not the battery or the connections at the battery! Any other ideas would be help full.
Dave

[777stickman]

Start relay in the underhood fuse block. Ign A fuse #6 40a in the same place. Crank fuse #8 10a in the dash fuse panel. Could be any of these or the ign sw or the Park, Neutral Safety sw. 1st check for 12v on the Purple wire at the starter in the "crank" position. If it's there most likely another starter replacement.

[j cAT]

Originally Posted by 010175

1998 suburban, owned it for 15 years, 220,000 miles, new battery, starter last year, cleaned connections by disassembling all parts at battery! The bolt out, the round lead thick washer out, ect. The problem is when I turn the key at times it acts like a dead battery. Jump starting works all the time. If I go from off to start with the key sometimes it will not turn the starter. If i go from off to on, wait 20 sec, then start, it will start. Is there a starter relay somewhere not on the starter that is going bad? What is the chance it the ignition switch? I know its not the battery or the connections at the battery! Any other ideas would be help full.
Dave

I would load test the battery , since a jump start stops any cranking issues.

at this amount of mileage replacing the ignition switch and the crank starter relay is a good idea .

any corroded wires should be replaced. the corrosion can work into the connector fittings reducing amps required to drive the starter.
the other Item would be the alternator output should be checked under full load. it is possible its only putting out 50% power as the diodes start to fail. also on shutdown will suck down the battery power [leakage of current].

[010175]

Well getting back with what was wrong. It was a losses starter cable at the starter. Replaced the starter last year and did not tighten the cable enough. That was it! Dave