[dj12122000]

I've noticed that the two 12V outlets don't work when engine is shut off, I have to switch on the engine to inflate my tires using tire inflator. Do you guys think it is normal? My 2002 Jeep liberty does't need to switch on during tire inflation.
Thanks

 

[volosong]

Per page 505 of the 2015 Owner's Manual, 12v 'cigarette lighter' outlets can only be used in "ACC" or "ON" position.

Should be easy enough to re-wire them so that they are always hot.

 

[Quickdtoo]

I wanted an always-on 12V outlet too, but rather than mess with the vehicle wiring I installed a receptacle in the rear of the console, ran a 12ga line under the edge of the console in ¼" loom to an add on fuse on the fuse block above the driver's kick panel. Real handy to charge my phone with a 12V 2-port usb charger.

 

[CB91710]

You should have the engine running anyways, and preferably connect your compressor directly to the battery.

Modern vehicles are loaded with electronics and they do not "like" low voltage at startup.
This is one reason that batteries used to give "warning" before they failed through slow cranking.
Now, when the key is turned, the computer simply won't boot up so you get no spark and no command to activate the starter.

Compressors draw a LOT of current. Not as bad as an electric heater, but they do draw a lot. Many, even though they have a lighter plug, can draw enough to blow the fuse.

 

[CB91710]

Per page 505 of the 2015 Owner's Manual, 12v 'cigarette lighter' outlets can only be used in "ACC" or "ON" position.

Should be easy enough to re-wire them so that they are always hot.

4.3 and older had a relay that could be jammed closed with a scrap of an old AAA card.
4.4 is apparently direct switched power.

 

[volosong]

I've pretty much dumped all of my old 12v inflaters and now use a Ryobi inflater. I like that you can set the psi and it will pump air into a tire until the pressure hits the limit you set. Batteries are expensive, but if you have other Ryobi tools, you can just use one of their batteries.