No reverse only forward

I just got this 02 ford think does not go reverse only forward any idea thank

…Error/fault codes?..

No codes , batteries were low which charged ok don’t see any blinking or solid light except batteries shows charged

when you switch to the reverse position, do you hear beeping?
Also check to make sure the key switch cable is connected securely into the back of the cluster.

Check the ignition switch operation. If you need a shop manual send me your email.