I have an E8 error message on my Haier hwr10xc6 Thru-Wall/Window Air Conditioner
I had a problem with my Haier Air Conditioner also and was getting an E8 error message. We had taken the air conditioner out to clean it and when we put it back in all we could get was the E8 error message. We tried several different things so I don't know if it was a combination or luck. Here is what we did.
First we tried holding in all the buttons on the panel and another person hit the on/off button on the remote (per a suggestion on the internet). The fan stayed on, but the compressor would cycle and it would get cold for a few minutes then kick off, but we never could get the buttons on the control panel to work. Nothing happened when we pushed them.
Then we checked the thermostat (the little tube in the front) . The thermostat tube was touching the coils. We rearranged the tube so it was not kinked or touching the coils. It was then getting cold, but we couldn't control the buttons. So we unplugged it (reluctantly because it was cool then) and plugged it back in and it started working. Hope this helps someone! I don't know if what we did worked or the mother board got wet and just happened to dry out or something.