all the test light is telling you is if there is power to the plug, not if it's actually working. it would be like testing a light bulb by measuring power at the switch... your tester would say there is power, but your EYES would tell you the light bulb is out.

you need to measure the amps it's drawing, or measure the ohms the plug is resisting to ground. or the best way to know if the plug is working is to pull it out and apply voltage to it, and see if it glows.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!