Diagnose steering wheel vibration

There are many possible reasons of steering wheel vhbrations. It also depend on the vehicle speed where the vibrations occur.

On car with a vibration on a low speed like 20-30mph, most likely you have a separated tires. That means one spot of your front tires is higher than the other points of the tire that touch the ground. To locate the taller spot on the tire, the low spot has more thread depth and the tall spot has less thread thickness. Make sure you replace the separated tire right away. This may cause a tire to blow causing an accident.
If the separated tire is located on the rear, there will be no steering wheel vibration on that speed but vibration on the rear of the vehicle.

On the car with a vibration on freeway speed like 60-80mph, press the gas then release, then you notice the vibration. that means you have a wheel balance issue. If the shop balanced your tire and still having thesame issue, ask the shop to perform a road force balance on your tires. this means their machine will locate the heavy part of your tire, and match it to the rim. they will then mark the tire and the rim and then align those mark to have a smooth ride.

On the car with a vibration on freeway speed like 60-80mph, but vibration occur most during acceleration, this means, you have an issue with your drive axle, or internal differential problem.

On the car with a vibration on freeway speed like 60-80mph, and only occur when slightly pressing brake pedal, you have a warped front brake rotor. To fix this, take your car to the shop and ask them to resurface your front rotor. Make sure they measure your rotor first before they resurface it if it is still in its service limit.