XJS HOOD (TOP) CONTROL MODIFICATION

Do you own one of those beautiful Jaguar XJS roadsters?  Tired of playing with the parking brake when you want to raise or lower the hood (top)?  There is a simple 10-minute answer.  But note you will lose the safety feature that prevents top operation unless the brake is on; Jaguar assumed erroneously that this meant car was stationery.  The author assumes no responsibility for your kids (or spouse) trying to raise or lower the top while going 70 mph so tell them what you’ve done.  

Open the boot (trunk) and A) remove the trim cover on the RH forward side.  You’ll see the battery and above it a shelf with the cylindrical hood pump/motor unit, black logic module, and a series of small cubical relays.  Notice the wiring from the logic module and the nearby multi-pin connector.  The black wire is grounded all the wire.  The black-with-white-tracer wire is grounded only when the hand brake is on.  B) Cut the black/white wire on the car side, not the module side, of the connector.  C) Take a short 4-6” piece of wire (about 18 gauge, solid is preferred to stranded) and strip ½” of insulation from both ends.  D) Push one end into the connector hole for the black wire and the other end into the black/white hole, both so they contact the pin crimped onto the end of the existing harness wires.  Be sure no bare wire can touch any other connector pin and the wire is not likely to fall out.  Double it up if it’s loose.  E).  Test it and F) replace the trim cover.  You’re done.

For the curious, your jumper tricks the module into thinking the brake is on (full-time) by grounding the black/white terminal.  Snipping the wire prevents the jumper from activating the Park Brake light on the dash; the light still warns if the handle is pulled up.

While you have the trim cover removed observe the 30 amp fuse for the pump motor and the arrow-like black valve in the plumbing on top of the motor.  If you should ever have a pump failure you can turn the valve to the manual position, as noted on the decal on the unit, and then manually raise or lower the top.

About the author. Jim Morton is the proprietor of Morton Restorations, Greensboro, NC, (336)-294-3436