I found my Right front air spring dropped one night. Mmm i thought leak on the air spring.

So what I did then last night was to lift the Car to offload settings and took out the Air spring Relay under the seat.

Then the wheel that looked like it had a leak did not drop, but the other wheels drop. (The rear dropped the most.)

Where can a person start looking for a leak. I did use some soap water in a spray bottle but not pick up any leaks.

Depends where the leak is on the bags. Sometimes if the leak is where the fold over, when straightened they don't leak and vice-versa. Don't know how old yours is but mine is 12 years old and all 4 bags were knackered and had to be changed.