i would like some t/s steps or most likely causes.
the backup sensor is off all the time. i can turn it to on as long as i am in any gear except reverse. when in reverse it will stay off. when i try and turn it on it will blink once and stay lit( off islit up).
any help would be appreciated.

2004 e/b 4x4. 105000 miles.

wow, dont everybody reply at once. thanks for all the help, fellas.

Could be a problem in the PAM (parking aid module).. A diagnostic testshould be done to look for any PAM DTC's, and/or module communication..