Turning on the AC and the dash light up so it must be the Alternator. Reminds of the story of the deaf frog. A man taught a frog to jump when he said jump. The man remove one of the frog's front leg and yelled jump. The frog jump, but not very far. The man remove the frog's other front leg and yelled jump. The frog was still able to jump. The man removed the frog rear leg and yelled jump. With great effort the frog was able to hop on one leg. The man remove the last rear leg and yelled jump. The frog just sat there. The man continues to yell jump but the frog continues to sit there. The man's conclusion was that after removing all the frog's legs, the frog turns deaf.

Maybe the AC compressor is putting such a load on the engine that it is not able to spin fast enough to generate the needed voltage. Normally when the AC is turned on the idle speed is increased to compensate for the additional load. Could be the compressor is loading up the engine, but that just a guess on my part. This guess is base on the daughter's explanation/observation "that when it comes on you lose a lot of power".

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2006 Infiniti G35
2001 BMW 3.0I E53 X5 Build date 08/2000 SOLD
Lotus Europa 1970 Destroyed by fire
Lotus Europa 1970 S2 Renault Powered
Lotus Type 52 1970 Twincam Webers Powered
PORSCHE 911 Targa 1982 The Garage Queen
Audi Avant donated to Kars for Kids
BMW 525IT Sold
Audi 4000CS Quattro Sold
Jensen Healey Lotus Powered Sold
Opel 1900 Sold
Triumph Spitfire 1971 Sold
Triumph Spitfire 1968 Sold
Plymouth "Cuda" 340 Six pack SOLD