Red Lamp Light

The problem lies in the heat sensor that sits just inside the lamp housing area inside your set. Apparently the technician fix is to clip the faulty connector Mitsubishi used when assembling the set and replace it with a soldered connection instead. My fix is simpler and does not require solder. My TV is a 57831 model so it may differ from others but not much if so. Here is what I did.

1.) Remove the two screws holding the lamp door to the set in the back lower right corner of your set.
2.) Follow the set instruction for removing the lamp assembly. it should be unplugged for an hour prior to doing this.
3.) Once assembly is removed, grab your flashlight (if necessary) and look inside the housing. You should see a white rectangular shaped piece attached to the outer frame edge of the opening. Looking straight on, it is located in the upper left corner of the square opening and is held in place by one small phillips head screw. This screw is inserted and installed from the opposite direction and will require the short screwdriver to remove. Carefully remove it and don't drop inside the set!
4.) To make room to move around and do what you'll need to do, you will also need to partially remove the back cover of the set. Mine was limited to just the lower half and was held in place by nearly 20 screws. You don't need to remove all of them but do need to be able to open up the rear enough to access the connecter that sits on top of the upper left edge of the lamp housing. If you follow the two yellow wires from the white sensor, they track back to a small black connector with two black wires on the other side of it.
5.) At this point, you have removed the screw to the sensor. Now you will need to pull the connector wires free from the routing clip on top to free up space for the wire to move freely. Once these two black wires are pulled from the clip, pull the white sensor down from it's position to free it from it's housing and allow the yellow wires to be pulled from the left side of the housing out. If done right, the sensor is free now and can be pulled carefully by the connector at top and out the back of the set.
6.) Squeeze the clip connection where necessary and pull the clip assembly apart. The sensor is now free of the TV entirely and you can work with it separately.
7.) Grab a nail file and work the connector pins a little to roughen the contact points a bit. This is similar to cleaning the contact posts on your car battery.
8.) Push the male end of the clip firmly into the female end until it clicks and then push a little harder to be sure good contact is made.
9.) Do the reverse as done above to put it all back together again and power up!
10.) The message should now be gone.