Red light on,check filter - LG WM-3677HW Front Load Washer / Dryer

I love my LG combo unit and it saves me hours and hours! I've had it for five years.

The laundry seems to wash itself. I put it in dry-and-dirty and take it out dry-and-clean. It eliminates "wash day" because all you have to do is load it up before you go to bed or go to work and hang it up when you get home. And no more chapped hands from moving the wet laundry around!

I have a tip on the lint trap. (I am asusming by now that you checked your owner's manual and know how to empty it.) That lint trap seems to be the most common problem I've read about online. What I do is cut apiece of plastic mesh to 2.5 x 4.5 inches. (I find the plastic mesh that comes under some carry-out pizzas works best.) I roll it so that it fits into the lint trap as an additional filter. It will be open at the back just like the main filter. It catches ten times as much lint! And if you forget to check it, it will trigger your OE light sooner, so your water pump will last longer.

Is this a ventless dryer? I.e. a condensing dryer?
If so, there is a filter that filters the lint out of the water in the condensing unit. Check your owner's manual to find out how to service this. It is usually a little door on the front, bottom of the unit.
If it is not a ventless dryer, then the only filter I know is the lint screen.

Good Luck!