Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Doesn't actually fit all first generation Tundra

There are three factory stereo configurations for first generation Tundras. There is the stock OEM system with two ten pin adapters. As far as I know this adapter will fit these. There is also a "factory upgraded" stereo with an amplifier in the dash (early Tundras) or under the right rear jump seat (2005-06 Tundra). These use two 20 pin adapters. This harness will NOT fit and even if you somehow made it fit, it wouldn't work because the amp will not turn on. The third option is the widely known JBL upgrade.So if you are considering replacing the factory stereo in your Tundra make sure what you have first. If you have tweeters in your front doors, but no "JBL" identification on the stereo, then you have the factory amplifier option and this will not fit.You can buy an adapter (Tato for the JBL system) that will work on the non-JBL amplified system. Just be sure to follow all of the instructions carefully.