Amend CSSB 1863 (house committee printing) as follows: (1) In the recital to SECTION 4.16 of the bill (page 17, line 26, strike "Subsection (c-1)" and substitute "Subsections (c-1) and (d-1)". (2) In SECTION 4.16 of the bill (page 18, between lines 9 and 10), after added Section 162.227(c-1), Tax Code, insert the following: (d-1) A license holder may take a credit on a return for the period in which the purchase occurred, and a person who does not hold a license may file a refund claim with the comptroller, if the license holder or person paid tax on diesel fuel and the diesel fuel is used in this state by auxiliary power units or power take-off equipment on any motor vehicle. If the quantity of that diesel fuel can be accurately measured while the motor vehicle is stationary by any metering or other measuring device or method designed to measure the fuel separately from fuel used to propel the motor vehicle, the comptroller may approve and adopt the use of the device as a basis for determining the quantity of diesel fuel consumed in those operations for a tax credit or tax refund. If there is no separate metering device or other approved measuring method, the license holder may take the credit and the person who does not hold a license may claim the refund on a percentage of the diesel fuel consumed by each motor vehicle equipped with an auxiliary power unit or power take-off equipment. The comptroller shall determine the percentage of the credit or refund. The climate-control air conditioning or heating system of a motor vehicle that has a primary purpose of providing for the convenience or comfort of the operator or passengers is not a power take-off system, and a credit or refund may not be allowed for the tax paid on any portion of the diesel fuel that is used for that purpose. A credit or refund may not be allowed for the diesel fuel tax paid on that portion of the diesel fuel that is used for idling.