The Icom AT-130 is compatible with the M-802. However, you need to determine if the AT130 you have is working correctly. A power/swr meter would certainly be helpful in doing the testing.
Meanwhile, check and re-check all connections from the radio
to the tuner and from the tuner to the antenna
and RF ground system. Be especially careful in examining the Molex connector for the control wire between the radio
and the tuner, particularly at the tuner end. This is a common source of trouble. The pins are flimsy and sometimes don't make good contact.
Also, the control wire connectors are NOT waterproof, and surface corrosion
often creates problems.
BTW, the 802 itself is not even splashproof, much less waterproof. But, hey, what can you expect from a $2,000 radio, anyway?
The "Tune" LCD should blink while the AT130 is seeking a match, and will go solid "Tune" when it's finished tuning. However, you don't know how good a match has been found, if any, unless you either have an external power/SWR meter or you get an approximate indication from the SWR/power out indicators on the control head
One advantage of the AT-140 tuner is that it will show "THRU" when a good match has not been found and the tuner is essentially passing RF directly to the antenna
. However, with an external cross-needle SWR meter (like the Daiwa CN-101L...my favorite for boats), you get a good visual indication of transmitter performance and of antenna tuner and antenna system performance.