Not sure how to set my split system LG for cooling

Generally, they are operated by a remote control (similar to a television), although some units do have a wired wall control option as well. The indoor and outdoor unit has sensors that measure temperature (to control the operation of the mini-split) and (once the remote is set) the sensors control the system until it reaches the set point set on the remote.

Keep cool mode and temp setting 23 degree. And more information,

www.retrevo.com/support/LG-LA091CNP-Air...manual/id/.../t/2/

Hope it's helpful.

It sound like a defective receiver pcb. Have this professionally checked. I take the time to help, so please rate me!

Sound like a defective receiver board. Have this checked. Also check to see that your remote transmits. Hold the top part of the remote to your phone or digital camera lens. press a button and a light should appear on the screen of your phone or digital camera screen.
Hope this helps I take the time to answer your question so please rate me

If the units are close to each other they will both read the same setting. You just have to get the remote really close to the wallmont air handler you want to command.

Is this a heat pump or just straight a/c?

On the remote, press the mode button (might also be labelled master control) until a snow flake appears. Then set the temperature for 23 degrees. The speed of the fan can be changed by the fan button. All functions should cycle through so if you go too far, just keep pressing the button until you get back to the desired setting.

I could not find a "fault code" list for the LA125HV but for thier Multi Split Units LG lists code CH7 (C7) as "Indoor Unit is Set in Different Cool/Heat Operation Mode." So maybe your air-handler tihinks it's in Heat mode will the compressor is in Cool mode, or vice-versa....

make sure outdoor unit is running if it is may have low freon if not check power at outside unit

We have an LG Split System with a Remote Touch Screen Control Panel. There is a message flashing "CH46". How do we fix this?