Converting Your Jaguar To Negative Ground

All Jaguars equipped with a generator (AKA "dynamo") are positive ground (AKA "earth"). There is no theoretical advantage to negative over positive ground, but if you want to fit modern electronics such as a CD player, you'll have no choice but to convert to "normal" polarity.

It's also an advantage when your car might require a "jump" from a modern car and the uninitiated are involved: there's less of a chance the cables will be connected incorrectly.

Here's what's involved with the switch:

• Reverse the battery connections so the negative cable becomes the ground. This may require a new cable or some re-arranging of the battery.
• Polarize the generator. Use a jumper wire from a hot source (such as the starter solenoid) and brush it twice against the "F" terminal on the back of the generator. The "F" (or "field") terminal is the smaller of the two. If the terminals on the generator are spade type, it might be easier to remove the first remove the "F" wire for better access. This procedure can also be accomplished by simply jumping between the A and F terminals at the control box. Use a screwdriver, penny or wire and simply brush against these terminals twice.
• The ignition coil on a positive-ground car will be labeled SW (for ignition "switch") and CB (for "contact breaker", or the wire that goes to the distributor). Simply reverse these connections so that the SW post is connected to the distributor and the CB post is connected to the ignition switch.
• Ammeter/Voltmeter. Reverse the leads or the unit will read backwards.

That's it!

Note: The latest "electronic" or solid state, SU fuel pumps are polarity sensitive. They may fry themselves if connected to opposite polarity.

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