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It has a single purple wire that connects to the sensor. To check the gauge take the plug key on and ground it and the gauge should peg full hot. Even in the UK the sensor should be available for a fair price.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184