Also a handy reference and parts source is XKs Unlimited, Jaguar XJ Parts Master Catalog Series, This one has great parts illistration's
Also SNG Barrett catalog

 

The one for the ALT is short all the way aft that is #4

 

I think I found it (on the picture). It looks like it is hiding at the bottom in the background

Also, thanks for the tip about checking for parts diagrams in the SNG Barratt catalogue. Found the description:


Thanks! Happy New year!

 

In your photo # 1 is the ALT adjuster. #2 is the Power steering. #3 is the compressor (AC) and A/P adjuster. The jockey pulley (J) is the tension device for the Fan (F) under the Fan attach point.

 

Happy New Year to you as well good wrenching