Yesterday, took the time to remove the electrical panel on my JD4400. I was trying to see if there was a good way to connect to external outlets. From my inspection the panel had an accessory fuse position "I didn't have a fuse there, maybe robbed it out at some time" however I couldn't see where this fuse was powering. I don't recall a seperate panel anywhere. The other outlets were simple...powering key switch, lights and normal things running. I can say from looking at it, that they really didn't mean to encourage anyone hooking onto the panel. When I put the power for the multiplier..I tied into line on key switch so it would be positive electrical shutdown. I know it's possible to have an electrical fire and I strongly suggest folks really examine their electrical tie ins. I do have the service manual, but the electrical is like trying to understand the book of revelation. The 4400 does have some kind of instrumentation computer module but not very sophisticated. My biggest beef with my JD4400 is the plastic breakup...after 22 years, plastic tabs are broken, I've used fiberglass repairs on a lot of stuff. I think there is programs and write ups of plastic versus metal and on this score the plastic really looses....but anyway passing on the electrical take...good luck on service of your units...