XJS Hood (Top) Control Modification

by Jim Morton


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 youve done.  

Open the boot (trunk) and A) remove the trim cover on the RH forward
side.  Youll 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 its
loose.  E).  Test it and F) replace the trim cover.  Youre

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