# 2000 mercury cougar lights



## rodsteryz (Oct 12, 2007)

The interior lights and the headlights "surge" in about 3 second intervals going from bright to dim. Putting a tester on the battery with the car running it fluctuates from 14 to almost 16. After doing some research it sounds like it as a huge pain changing the alternator on this car so I wanted to check here for any other possibilities before changing it. I will also take it to a shop tomorrow to have alternator checked. Just wanted to check with all of you first as I trust you guys WAY more than any service shop! :thumbsup: Any suggestions appreciated. Thanx


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## nap (Dec 4, 2007)

is the engine surging in time with the voltage surges?

If you increase the engine speed and hold steady, what does the voltage do?


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## rodsteryz (Oct 12, 2007)

Didn't test it while reving engine in park but the lights still surge at the same rate as I am driving at a steady speed of 60 mph. The battery warning light in the dash also comes and goes off as it surges. Does not seem as though the engine changes as this is happening.


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## nap (Dec 4, 2007)

definitely an odd situation. I can't say I have a clue why you would have those symptoms. If you are near an Autozone or Advance Auto Parts, they do free charging system checks. (at least around here they do).


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## rodsteryz (Oct 12, 2007)

Thanks for the input. I'll go by and get it tested. I'll let you know what they come up with.


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## intropiles (Dec 31, 2010)

rodsteryz said:


> Thanks for the input. I'll go by and get it tested to sell my car online. I'll let you know what they come up with.


Okay man! I'll count on you. :thumbsup:


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