The original sub I had blew, it was flapping like crazy so I didn't play music for 2 months until I bought a new sub. I had the sub replaced but now the sub isn't playing. All other speakers are playing except the sub. The dealer took it out and tested it and it works fine. What do you think it is? A blown port on the Mark Levinson amp?

 

Well, if the sub works, then it's not the sub! That leaves the ML amp and possibly the connection harness. Did the new sub work OK for a while right after it was replaced?

 

It never worked when they installed it. I think I'll have to get the Lexus dealership to diagnose.

 

Who is "they"? The dealership (in which case, they need to fix it on their dime) or an auto stereo store (in which case you may be on your own)?

 

I had a local Toyota dealership install the sub for me. They said they don't have a system to diagnose my type of vehicle only Lexus does.

 

Are you sure the original sub was, indeed, blown? An amp going out can produce LF distortion that might sound like a blown sub. All points to the amp. Might be time to bite the bullet and take it to a Lexus dealer for confirmatory diagnosis. If it is the amp, send it to United Radio for repair (less than 1/2 the price of the dealer refurb replacement).