Very similar to one I had on my 99 until last week. When I bought it there was evidence of an alarm and other electronics being installed once upon a time. I always thought my box was a small brake controller until one day a couple weeks back it started beeping at me and my rig wouldn't start. I unplugged it, plugged it back in, and presto my jeep started. It did it a couple more times, so I dug in and found it was attached to my ignition so I think it must have been some sort of old auto start or something. Glad it is gone now! NO more extra electronic BS on my Jeep!

 

I don't think that its a knuder valve. It looks more like the Panadermic Marzelvane!