Originally Posted by Bill G
It needs to go in the suction ( low pressure side). Most low pressure ports are on the accumulator (dryer) which is is round black canister that will be on the passenger side firewall connected to a box that sticks out of the firewall.
Your truck should take 134a but check the cowl tag just to be sure.
Thank you guys for the help. I realized I was trying to connect it to the high pressure one, which made sense why it didn't connect. After I put on the low pressure on the passenger side, it worked just fine and now I'm ready for the summer