When I start the fireplace it’s on high. When I go to lower the flame it shuts off.

SOURCE: Gas fireplace pilot flame won't stay lit.

Hi , you can try and pull the panel on the bottom of fireplace out and check the adapter in fireplace. Sometimes they go bad. When you open in also check to see if there is an adapter plugged in and a option to use the battery operated function. If this goes bad the pilot will not stay lit.

SOURCE: my heat n glow fireplace comes on fine with all

You may have a few sensors, one may be a thermopile that energizes the pilot. It is a very thin but long bulb located in the pilot flame. Then you may have something called a thermopile which is also located in the pilot flame that energizes the main gas valve. It is a larger diameter bulb and will have metal wrapped wireg going to the gas valve. If the pilot stays on but the flame goes out under the logs, change your thermopile and look for a bad connection at the gas valve or switch. If both the main burner and the pilot goes out you may have a gas valve problem or a plugged vent pipe. If the flame just disappears it is most likely a gas valve. If the flame changes colors and lifts from the burner, that is a sign of a plugged vent. Good luck.

SOURCE: my fireplace starts up just

the fan on most fireplaces incerts and free standing is turned on by a click dics. if you see no change in your fire then chances are this switch is bad. follow the wires from the fan and you will fine this switch. there will be another one that protects from over heating so make sure you have the right switch if your comfortable jump the fan switch, 110volt, and if fan runs wala find a dealer and buy new switch.