Slippage marks are used to detect movement of the inner tube inside a tubed tire. When a tire has a tube, the tube can slip or rotate relative to the tire and rim under pressure, which can lead to improper seating or pinch flats. Marking the tire and tube lets you see any subsequent slip during service. This requirement applies because a tube is present, not because of a specific pressure value. Therefore, a tubed tire at 160 psi should have slippage marks. Tubeless tires don’t have an inner tube, so this check isn’t needed for them.

The size is chosen to give enough coverage for the label while still fitting snugly around the hose after shrinking. When labeling hoses in an engine area, you want a clear tube big enough to fit over the hose and the label and then shrink down to a secure, readable wrap. A 2-1/2 inch final recovered diameter provides that balance for typical engine hoses: large enough to cover the label and a section of hose, yet small enough to shrink tightly and stay in place. Smaller sizes wouldn’t fully cover the label, and a much larger size would not form a tight, secure wrap. The result is a protected, legible label that can withstand heat and fluids in the engine bay.

Understanding how to read connector codes on the wiring diagram is essential for tracing circuits and verifying installations. For the ATF3 lead generator T3, the diagram shows its lead wires terminating at a specific connector. The code X5017A6B identifies the exact connector and harness variant used for that circuit in this configuration. The X prefix denotes a connector, the numeric portion pinpoints the particular unit, and the suffix A6B indicates the harness variant and position used here. Because the T3 circuit in the diagram routes to X5017A6B, that code is the correct match for this installation. The other codes refer to different connectors or harness variants and would not align with T3’s wiring and pinout in this setup. To verify on the actual schematic, locate the ATF3/T3 symbol, follow the wiring to the connector legend, and confirm that the connection shown is X5017A6B.

When refrigerant is needed, the sight glass will show bubbles. This happens because the pressure drop through the metering device causes some of the liquid refrigerant to flash into vapor as it passes the sight glass. In a properly charged system, the sight glass generally looks clear with a steady flow of liquid and little to no bubbling. Vapor lock isn’t the typical observation here; it would imply a blockage or obstruction due to vapor buildup, not just undercharge.

Maintaining cabin pressure at altitude is done with an automatic feedback loop. The crew selects a desired cabin altitude, and sensors monitor the actual cabin pressure. The pressure controller compares the sensed pressure to the setpoint and automatically commands the outflow valve to open or close. If cabin pressure is too high, the valve opens more to vent air; if too low, the valve closes to retain air. This automatic regulation keeps the cabin at the chosen altitude while also managing the rate of pressurization and protecting against overpressure with relief valves as a safety backup.