Originally Posted by HSHADOW96
I have a 2002 Jeep Wrangler 6 cyc that won`t start, I turn the key and get nothing, radio and inside fan came on and that was it. Thought is was a fuse checked all and they looked good so next I replaced the starter with a new one and put a charger on the battery, it was good and still won`t start. I checked this forum found it could be ignition problems so I replaced the ignition switch and actuator pin, still nothing. HELP PLEASE
First off welcome to the forum, you've come to the right place.
If you know your way around a VOM (VoltOhmMeter) that would be helpful. I hate to see people throw their hard earned money away swapping out parts that are not bad.
Confirm you have battery voltage with a voltmeter, position it where you can see it from the driver's seat. You should have around 12.2-12.6 volts DC. If you do not then no need to go any further until you determine the problem with your battery and/or connections or charge condition.
If you have good battery voltage then turn the key to the "RUN" position, you should see a very small voltage drop as the dash lights come on and the fuel pump primes. Once the pump quits running (it only runs for a couple of seconds to prime the system) then turn to the "START" position. Watch the VOM as you do this. The voltage should only drop to around 9.5-10 volts under normal circumstances and the engine is turning over. If there is no change in the voltage reading then you have a problem with either the start "switch" or the starter motor as the brushes are not grounding properly. It could also be a faulty ground cable but it would have to be completely disconnected for you not to have any reading.
If the voltage drops to say 4 or 6 volts then you have one of two problems. You have either a voltage drop in your positive or negative battery cable/connection/circuit or you have an internally shorted battery.
A cable connection is somewhat easy to track down if you know how to perform a voltage drop test. Place one lead of your VOM (DC Volts scale) on the positive post of the battery and the other lead on the terminal. Try again to start, as current is flowing across this terminal any added resistance from a bad connection will show up as a voltage reading. Normal on high voltage side is only about .2 volts DC. If you see one, two, four volts or more you have a bad connection.
If that checks OK, then proceed to the next connection point. Leave one terminal on the battery post and move the other lead to the next connection further away from the battery, such as the connection on the starter soleniod. Same procedure but this time you should only have .4 volts or less voltage drop. Keep going until you have checked the entire circuit all the way to the starter motor. Then move on to the negative cable and test in the same manner.
It actually sounds harder than it is, once you see how the meter works and move the leads around it goes fairly quick to perform this test.
I would almost bet you are going to find a connection in the negative cable where it mounts to the frame or between the frame and engine as these are common corrosion/poor connection points. Especially on Jeeps that see jarring and vibrations from off-road and extreme exposure to the elements.
I hope that helps somewhat. Keep us posted on what you find.