Turn Signals, Hazards, and Main (high) beams stopped working in my 2005 X-type. Lots of surfing through threads on this site, with valuable guidance especially from Thermo. Tried everything suggested with no luck, and came to the conclusion that it must be the GEM (a/k/a GECM). Had a devil of a time finding out where it was located (I've never been able to download a usable copy of the JTIS, which requires considerable computer knowledge to pull off), but finally found a recall TSB that showed where it is: on my LHD 2005 X-type it is above the passenger’s right foot, piggybacked on top of the engine control module, and remarkably easy to remove (by Jaguar standards) by depressing a small tab on the cradle that holds the GEM. Picked up a GEM at pull-a-part from a 2002, but it was the wrong part number and didn't fix the issue, which I assumed was due to the different part# and/or the electrical changes that occurred in 2004. Then I ordered a GEM for a 2006 from ebay for $50, and it arrived in good shape. Tried it, but didn't fix the issue, which left me with two possible conclusions: either a) the GEM I bought on ebay was defective, or 2) it was never the GEM, and I needed to go back to the drawing board. I opted for #2 and dove back into the forum.

Most of the threads discussed pre-2004.25 X-types, which had a different array and descriptions of the fuses. One post talked about how difficult it was to decipher the descriptive language used in the owner's manual fuse guide, and a light bulb went off above my head (metaphorically in this instance, but with these cars anything is possible). In the pre-2004.25 models the fuse that controlled the main beams, hazards, and turn signals was in the engine compartment fuse box. In the post-2004.25 X-types, though (well, in my 2005, at least), the relevant fuse was F35 in the passenger compartment fuse box. The manual calls F35 the fuse for the “Direction Power Module”, which I had never translated from British English (or British Automotive Engineer English) into anything relevant to my issue. They couldn’t just say “turn signals/indicators, main beams, and hazards”, could they?!

Long story short, if you have this issue your first step should be to look at fuse F35 in the passenger compartment fuse box, in spite of its inscrutable description in the owner’s manual fuse guide. If that fuse is fine, then God be with you, as you’ll have to follow the guidance offered by Thermo and our other fellow travelers in X-type world in the other threads addressing this issue, e.g., check the wires for abraded wire coverings and shorts; use a jumper wire to check the harness that connects to the turn signal switch and see if you can actuate the signals by directly connecting the black power wires to the various colored wires; failing that, shop for an appropriate GEM on ebay for your model, plug it in and pray (and then try to get the security code reprogrammed if it sets off your alarm everytime to open the door).

Best of luck, and thanks to everyone offering advice on this utterly invaluable forum for X-type owners, especially Thermo, the master of all X-type electrical conundrums.