I have a 1999 XJ and fuse 21 or 19 blows. fuse 21 is the PCM and Coil and 19 is the auto shutdown relay. the code is No ASD Relay Output Voltage At PCM An open condition was detected in the ASD relay output circuit it all started about a year or two ago I got a death wobble and she died replaced the fuse and started right up, but two months later later later later it happened again. now it does it whenever it wants, sometimes when I put it in gear, sometimes when I park it and turn the key, but the hard part is I can't make it happen. sometimes it will blow 2 in a row sometimes it's just one. it's driving me nuts I think I might need to replace the PCM but I would think it would do it all the time. some people said the alternate but I can make it happen to test if that would fix it. I've tried looking at all the wires to see anything melded or otherwise bad. The hardest part is it can go Hours or Weeks without it happening

 

surely a fuse blow in that situation is due to a split or crushed wire that is intermittently shorting

I would carefully remove the PDC and examine the wires underneath

take a lot of pics as you go, so you are 100% certain where the wires go

there is a special technique for hunting shorts that uses a home made flasher circuit wired in place of the fuse, shake the harnesses and wires (or just use fuses)

 

Thank you tried that it been 5 ish days and same problem