When you see the signs of a potential problem with your Lexus alternator, there are a few simple ways to test its function. Of course, the first step is to know the signs to look for. One common sign of a malfunctioning Lexus alternator is a reduced function in vehicle accessories, such as dimmer lights or slow moving power windows. If you switch on the air conditioner and your dash lights dim, there is likely to be a problem. Now, to find out if your culprit is indeed the Lexus alternator, without the need to take it apart, you will need a voltmeter. First, you will need to start the vehicle, and get the engine up to a fast idle. Then you will need to set your voltmeter to DC, and measure the voltage across the terminals of the battery, with the red wire of the voltmeter on the positive terminal and the black wire on the negative. The reading should be approximately fourteen volts of power, if it is twelve volts or less you probably have a failed Lexus alternator, and will need to test no more. If that test was within normal range, the next step is to turn some of the power drawing accessories, such as the heater, the rear defroster, radio and headlights. Then rev up the engine and check the readings again. If the reading is less than thirteen volts at this point, you probably need a new Lexus alternator. If so, we have a selection of quality Lexus alternator replacements in our online catalog, all at great prices. You will find our secure site very efficient for placing your Lexus alternator order, or if you prefer, our toll-free line is just as convenient.