The fuse panel cover says 2 amp, the official manual I have says 3 amp, and a PDF copy of a 1989 XJS electrical diagram has it listed as a 7.5 amp.

I discovered this trouble shooting my locks. I replaced the solenoids and added an aftermarket remote locking kit. They worked for a while with the 5 amp fuse that was in the stock location but are now blowing a 5 amp fuse. But they are NOT blowing the 7.5 amp fuse I used after searching the PDF electrical diagram.

What say the experts?

 

And to expand my inquiry: The aftermarket remote lock system I used has its own fuse, a 10 amp one. Could it be that the aftermarket remote lock system is overwhelming the stock fuse?

If that is the case, would it hurt to keep the 7.5 amp fuse in there?

 

No it will not hurt to keep the 7.5amp fuse. The fuse is there to protect the wiring and other components from a failure. A total short will blow any fuse (within reason).

 

I appreciate that expert opinion. After looking at the wiring for the door locks it is normal sized (don't know exact gauge) as compared to the rest of the wiring and is certainly capable of handling more than 3 amps. I've been using the 7.5 amp fuse for several days now and it is holding. I think the combination of the keyless entry and new solenoids mixed with ancient English curses overwhelmed the 5 amp fuse and the sweet spot is 7.5 amps.

And I agree, a total short will blow any fuse.

 

Ah new aftermarket solenoids this now makes sense, (sorry I missed the replaced solenoids in your first post) if the solenoid coil is lower in resistance than the original Jag units they will draw more current, hence the blowing fuses. Most general wiring in cars is rated at 10A

 

My repair operation manual for 1990 model year onwards lists 10A as fuse rating for central door locking