How do I charge the ac system on a 2005 mercury gran marquis

there is a shroeder valve on on the high side big expansion chamber is located near the top of the "big hotdog" there~note the sightglass for unscheduled bits of drier and expansion bubbles~

Always charge on low side/suction line is the larger refrigeration tubing with insulation tape in some parts, your charging kit will only fit that fitting. Your ideal charging pressures should be around 31psi as long as there is no restrictions.

oops low side~

Judge Roy you are only human, it's going to be hard to remember everything that you were taught, for instance last week I answered a question about torque specification, I said psi instead of ft.pound. now that since high school and that was in the mid seventies.

double oops...you know was dragged into this CarGurus affair by David Hutchison (DavidH25, or number one/two guru)...such a gentleman...leads by example...I am an Engineering type with some Mechanic experience 93-96...am still learning....the new ways....strange new world...my meteoric rise to 25,875 is not because I'm a dummy, but have a basic understanding....still have to verify that the evaporator is the hot one and the condenser the COOL one~....and worked as a refrigeration tech for the years '82-'84~shame and pity.~

....always have the handy excuse for bein' here, was taken out of the workforce in 2004 due to MS...MRI's are disgraceful but has given me an opportunity to share what I know that may help...and am a giant fan of Click and Clack...and have learned things that got me thru my mechanic's career 93-96~

Out of respect, you are very knowledgeable.... no one can take that away..as a matter of fact you even helped me out with a problem I had with one of my BMW. I am not a auto mechenic by trade... I am a retired HVAC TECHNICIAN, presently working has a Plantoperator for a 23 story building. Back to our topic the condenser is the high side (hot) it dissipate the heat which was absorb from the evaporator located in the control space. Let me know what you find out with your research. Let me know either way. Thanks Mr Roy.

Thank you guys for my answer to my Question! Also making me feel less stuped about something I should alreedy know. Thank You Anna

laxley and AnnaZ, thank you two for spreading some Positive energy my way...need all the kudos I can get...sort of buddhist where my only purpose is to make things easier for YOU~