MAF Adapter Harness With IAT Plug Series 3 III to LT1 This is a harness that is made for Series III cars that are going to convert to the LT1 MAF, most common for turbo setups. This MAF does not have an IAT built in, so it comes with an end that allows you to install a IAT sensor from a Series II car. An IAT extension will allow you to move it where you would like within the extensions range.