1999rodeo I wash the motor and its trying starts up by its self what's my problem u think

When you get the not so water proof connector apart and dry it out which you should do as if you just leave it to dry by itself it may corrode, when you put it back together fill the connector with dielectric grease so no moisture will be able to penetrate it again.

You have water intrusion past the Weather-pak seal on the wiring harness to the starter solenoid relay. You can try spraying WD-40 or similar short-resolving fluid into the wiring harness connectors, until the problem stops, or you can wait for the harness to dry out naturally. USE CAUTION, SUCH FLUIDS ARE USUALLY FLAMMABLE!

I don't recommend trying to turn on the ignition, as it may cause the starter to grind while the engine is running, causing damage to the starter and the flywheel/clutch.

As already posted, unless you have a very good reason to, hosing off/steam cleaning and engine is really not recommended.

Sorry to say-- we have not washed motors
for the last 25 years, because of what you have

(Problems with water intrusion)

Start taking it apart & use an air hose to remove
any water you find