I was charging up my battery on my 1982 XJ550R Seca after replacing the clutch and my buddy crossed up the leads to the car, sending a negative to my positive terminal and vise versa. After a quick spark my gauges went out and no sign of electrical life was present, no horn, no neutral light, nothing. What should I check out? Are we talking complete electrical overhaul? I checked the fuses under the seat and they all seem fine. Is there a main fuse that could have gone, or did I fry an important component?