I have had luck replacing batteries but more often the circuit board is damaged beyond my ability to repair. I bought a handful of relays and re-wired the drivers seat operation in my 95 RRC using the relays and eliminating the memory feature. The relays fit under the seat where the ECU had been. I only wired the seat motors and didn't bother with the remote mirror feature. It's been several years since I made the modification and the relays have worked fine and have been more reliable than the direct wired switches in my 89 RRC.
I just traced out the wires and inserted the relays in place of the circuit board using the existing harness that I cut off the beige ECU box under the seat.
I didn't develop a diagram. However, the LRO forum has a thread that does include a simple wiring diagram. http://www.lro.com/forum3/viewtopic.php?f=33&t=4955
Since I didn't follow this LRO version, I can't vouch for it. However, it seems simple enough and the color code appears to be accurate. In this diagram, the left column shows the existing seat switches, the center column shows the relays and the right column shows the seat motors.
2013 RRS
2006 RRSC
2002 DII
1998 P38 4.6
1995 RRC SWB
1989 RRC
1965 SIIA 109 SW