How to Locate the Low Side Coolant Fitting on a GMC Yukonby Jeremy Holt
The low side coolant fitting, also known as the low side charging port, is part of the GMC Yukon's air-conditioning system. The vehicle is kept cool when pressurized Freon gas is turned into a liquid by means of a compressor. The liquid is then passed through an expansion valve where air, cooled by the Freon, is blown into the cabin. Occasionally, the Freon in the air conditioner needs to be recharged; the low side charging port allows this.
Raise the Yukon's hood and prop it open.
Locate a canister wrapped in silver insulation at the back passenger's side of the engine -- this is the air-conditioning accumulator.
Trace the pipe that runs over the top of the accumulator from the fire wall forward, and locate a dust cap marked with an "L" approximately 5 inches away -- this is the low side charging port.
Access the low side charging port by removing the dust cap; turn it counter clockwise and pull up.
- speedometer image by Joy Fera from Fotolia.com