new here truck problems

[Jenetta Schmitt]

hi my name is jenetta..... i have a 99 gmc yukon denali 4x4 ..... ive had the motor replace when i bought it off craigs list last feb ... due to the motor not being the correct motor its was a older 95 modle so distribs didnt match up .... well the wiring harness was never placed back into correct spots to keep from melting.... iii i recently had my vehicle washed not realizing wires was exposed and the under spray got them wet.... well not its throwing all my sensors codes.. bank 1 sensor 1,2 and bank 2 sensor 1,2 ... and my transmission wont switch past to 3rd gear.. almost like its slipping ....does anyone have any kind of help maybe or some kind of direction to point me in.... i dont think the sensors are bad..... do u think if they was it would casue my transmission to act like this all of a sudden or the wiring harness doing something to it ???

[00Silverado4x4]

First thing I'd do is to get everything dried out and sealed up. Then go back and check for any and all possible codes in the computer. If you have wet wires it'll throw everything out of whack and won't give you an accurate picture of what is truly wrong.