Just got my 2001 disco II. I'm not very car literate but this forum is great and has taught me a lot already. Anyway, I'm trying to replace the #15 in the main fuse box under the steering wheel which powers the cig lighter and a few other things. Owner manual calls for a 20 amp fuse. Every time I put one it and start the car it blows the fuse. Any ideas?

Note- there was no fuse in the box when we got the car... Damage already done?

 

Yes, you have a short in the wire harness to the lighter, quit replacing the fuse or, if you haven't done it already, you may burn up the harness.
Leave the fuse out and take it to a local shop to have them test and repair it.

 

Seat heaters, vanity mirrors, lighter - you can unplug some of thse things to see if load changes, can test with an ohm meter rather than risking harness.

 

My 20A fuse is in tact and the lighter still does not function in my 2002 LR Disco II.
I suspect this too could be a wiring issue.

 

Ozzy : peek into the lighter socket for bent of stuck anything in there.

With engine running, apply a voltmeter probes to the nibs at both sides of the blown fuse face (where the 20A marking is). If there is voltage, the next new fuse you put in will likely blow.
If there is an anomaly inside the lighter socket, it can be unplugged at its connector by its back before installing the next new fuse.