A co-worker needs help. Her heater only works sometimes. she has to get the car to running temp and then shut it off and on a few times before it maybe works.

 

What exactly is not working? The blower? The switch? Without more detail, it could be a stuck thermostat, low on coolant, blower motor, blower motor resister, blend doors, etc.

 

Blower and Blends doors operate. Heat is come and go. I noticed yesterday that it was lossing some engine coolant at the fill cap. I suggested she replace it. As far as a stuck themostat? Idk. Its been really cold here lately maybe it is sticking.

 

If you're losing coolant or coolant pressure, that will cause the heat to be intermittent.

Coolant for the heater core is drawn from the engine side of the loop. A stuck-open thermostat usually makes it take longer for the coolant to get hot and thus provide heat to the cabin.

Get the cap fixed and make sure there are no other coolant leaks, and top the coolant off per the instructions in the Owners Manual.