Trouble with steering locking up

I bought my daughter a 2007 Chevrolet Impala back in October. When we test drove it and took it to our mechanic and they saw no problems. After our first rain, which was a week later, my daughter called to tell me that her steering wheel had locked up on her when she hit a puddle and she saw a message come up on her screen that says something about the battery. It only locked up for a few seconds then comes out of it. We took it back to the small car dealership and they changed the serpentine belt and tensioner and said that it should be fine now. Well…it hasn’t been fine. It still does the same thing every time it rains and she goes through water and the car dealer says that they can’t find anything wrong with it. She says that she goes through it slowly knowing that this will happen, but I am scared it will get worse and the steering wheel will lock on her and stay that way to make her have an accident. Do you have any ideas as to what else might be causing this problem?

You’re describing a slipping belt. Normally replacing the belt and tensioner would fix this type of problem. Perhaps one or more pulleys have gotten glazed or worn. Possibly there’s some sort of splash shield underneath the belt area that’s missing or cracked. A second opinion from another dealer or a good independent mechanic would make sense here.

For what it’s worth, I don’t think her steering is locking. She’s just losing the power assist, which means it’s much harder to turn the wheel. While this is being sorted out, she needs to keep two hands on the wheel at all times and be ready to grip and turn the wheel very hard if needed.

The belt is likely slipping and usually they slip because the tensioner spring is weak. If you have the 3.5L V-6 engine this is the part

other engines likely use a similar part. It is not difficult determine it that is actually the problem and if it is replacement is not difficult.

And the steering wheel isn’t actually locking. The power steering fails when the belt slips and it requires considerably more effort to turn the wheel but it will turn. Driving slowly through water is a good way to avoid a serious problem when doing so is possible.

If the belt and the tensioner were replaced, then the most likely scenario is that one or more of the splash shields underneath the engine compartment are missing. This is the type of thing that is not unusual when buying a used car.

Restore the missing splash shield(s) and the problem should resolve itself.