BrianK told me he replaced the FETs and relay. /QUOTE]
'relay'? There are two relays in the controller. The power relay which is on the +12v supply to the FET H bridge in the controller and the fail safe relay which I believe is between the negative terminal of the rack motor and the FET H bridge (its been a bit since I looked at the diagrams). Both relays carry the same amount of rack motor current and I thought that in Kaz's blog they both suffer the same problem and he replaces both. It might be worthwhile to confirm that relay is in fact both relays by emailing Brian K.
Checking the grounds is good. Do the rather simple checks in the service manual on pages 17-36 & 17-37 to diagnose a rack motor problem. Removing a rack is significant work that you don't want to do if the problem is elsewhere. My gut reaction is that if you had a
#25 error, did something and the
#25 went away and then reappeared, the problem is not the rack motor. Shorts or other problems in direct current motors tend to come and stay around, not go away. The tests in the service manual should confirm that.
I am of the personal opinion that leaving a battery on a tender for extended periods of time does not guarantee anything. Maintenance free batteries have a way of dying where they seem to be just fine and then 15 minutes later they are not capable of starting the car. A load test (or watch the voltage when the motor is cranking) is the only definitive way to confirm that the battery is in good condition. In April I took my NSX out of storage, reconnected the battery and my 8 year old battery started the car up just fine. However, the car was experiencing some electrical weirdness and about 1 week later the battery did the 'fine one moment dead the next moment' act. New battery and everything is just fine and the weirdness never re apeared. I am not saying your problem is battery related, just that maintenance free batteries can be deceptive.