Denso 210-0543 Remanufactured Alternator If you are needing to replace the alternator on your 2004 Toyota Sienna with the 3MZ-FE engine then this may help... The first step you will want to do is disconnect the negative battery terminal... This is the area of concern and were we will be working.... You will first want to remove the upper alternator bracket... You will now want to loosen the alternator belt by way of the tensioner.... Now we can disconnect the electrical connectors from the alternator.... Now remove the last alternator bracket and the two bolts holding the alternator in.... \ The alternator will come out through the top..... Now install the new alternator and make sure you check the operating voltage....