1998 Jeep Wrangler Dead, not in the water

Clarify "doesn't start". Does the starter crank the engine? If it cranks but too slowly, start by measuring the battery voltage. If it's less than 12.2 volts, charge it slowly for an hour, then, if it starts, measure the battery voltage again while the engine is running. Holler back with those numbers.

Doesn't even turn over, dash lights barely came on, could hear a slight clicking, then nothing. Thanks!

The battery is dead. Measure its voltage. It is supposed to be 12.6 volts when it's fully-charged. If you find around 12.2 volts, it's okay but discharged. Charge it at a slow rate for an hour. If you find it near 11 volts or less, it has a shorted cell and must be replaced.

If you charge it slowly for an hour, start the engine, then measure the battery voltage again. It must be between 13.75 and 14.75 volts. If it is low we'll have to test the charging system next.

I really appreciate your response, let me bring you up to date. The battery was fine, suspected the alternator, so I took it out and took it to the parts store. They tested it, said it was good. I explained what had happened and that the speedometer was dead. The sales person suggested that it might be the speed sensor. I found it and disconnected and then re-charged the battery. Sure enough everything was fine, (except the speedometer.) I bought the speed sensor, and everything has been fine for two weeks. Then this past Thursday the Check Gauges light came on and the battery charge gauge was pegged to the right at 19 volts. When I came to a stop, it went back to the normal 14. It did this again Friday morning, but then was fine Friday evening. I did not drive it at all on Saturday. Sunday morning it would not start. There is a low electrical hum when the key is turned, the dash lights are very dim, but it does beep to tell you that the door is open. Any ideas? Thanks in advance.

In regard to latest issue, cleaned battery terminals, it started right away.

Dirty or loose battery cables can cause the same thing that we warn about by removing a battery cable while the engine is running. That is a failure of the voltage regulator to be able to control system voltage to a safe level. That would explain the 19 volts and the failure to crank the engine. You may have solved both problems by tightening the cables.

In the future, when the generator needs to be tested, have that done on the engine. When you remove them to have them tested on a test bench, there are too many parts of the system that aren't included in the testing, and there's a few important parameters that can't be accurately measured.