I have been checking out this 05 Camry with 160K to buy used from a private seller. Its a 4cyl, automatic.

Seller states that warning lights on dash had suddenly came on and had actually had the car into the shop pior to have the issue fixed but it cropped up again. Seller now states the CEL is on, the ABS light comes on intermittently, and the speedometer drops to 0 sometimes while braking. Was also mentioned the power windows operate slower than usual. Seller was thinking the alternator since if the sensors that control the warning lighs are not receiving the proper voltage that could affect them and cause the lights to come on. Also as with the windows operating slower than normal.

The car was taken into the shop again and had a new alternator and battery cables installed but the issues remain. The shop couldn't find the cause of the lights coming on. 

Seller hasen't gotten back with DTC's yet, but does anyone have their thoughts and ideas as to the cause?