Cant get heat to the inside

Check the fuel pump if it is maintaining fuel pressure.

make sure the electric fan is working if not check the ground wires on the trans first

first off all if a/c gas presssure is low or no gas at all ( because of some reason you have already lost it) it acts exactly how you you describe. kicks in and out. but cant cool air inside. (first make dealer check it for leaks and let them fill it with proper yellow flourescent dye added gas)

limited het in cabin heater is another issue. if engine is warm and still not enough heat inside, we can say that you have a clogged cabin heater or air pocket is in hoses connected to cabin heater. you need to bleed cooler radiator inm front. you need to raise infront of car and bleed it with bleeding screw. after this check the heat again if still not enouh heat you may need to replace cabin heater.

if engine is not warm enough when you drive slow or let it idle. this means you have a broken thermostate or it is stuck half open.

I would check all the fuses first (on the left engine compartment) there is a 80amp fuse for high current...hope this helps you ??

You are doing the correct steps in finding the draw, you will need to continue these steps. check lights inside glovebox truck and etc, 5.80 is a big draw, make sure the horn relay is not shorting and the radio or trany seloiniod. you will need to start with the inside fuse box and pull one fuse at a time until the draw drops, im not sure the year make and model of this car so i cant give you ideas of problems ive seen but i hope this info helps and also have that battery tested for the heck of it.

your heater core is probably clogged try flushing the system

I expect the thermostate is stuck partially open not allowing the engine to come to proper temperature. Replace the thermostate found under the goose-neck (follow the upper hose back to the engine) under this piece is the thermostate. Be certain to clean all of the old gasket material away and use a new gasket. Watch to be ceratin the thermostate is not put in upside down, if this happens your issue won't be not enough heat but over heating.
I hope this may have been of help,
Tom

Several things ... best guess, in order:
1. (very likely) Radiator fan is not blowing (turn on car and a/conditioner.
When compressor kicks in, the radiator fan must blow). If it ims not blowing,
the radiator fan motor may be burned out ($40).
2. Check / replace "cooling fan" fuse ($1) and / or "cooling fan" relay switch
($7).
3. Radiator clog (possible)
Hope this helps!

have you chg. any thing lately like thermostate? added any coolent to system? if not, thermostate could be stuck in the open position. if stuck open, setting still, it will throw heat, but moving coolent flows to fast and does not get a chance to get hot. if you did chg. thermostate it could have a air pocket in the system. and also adding coolent can create an air pockets too. you will know this when your traveling down the road and temp guage fluctuates up and down. witch means air in system.

I have the same problem with my 2001 Tahoe. The front blower is working, its blowing strong, but its cold air even with the temp setting as high as it can get. The rear blows hot air. The engine temp guage is at about 210ish which is close to being normal (220). I just replaced the thermostate a few months ago, I don't know if its bad again, or it I deluted the antifreeze too much and it frooze the heater core, or if the heater core just went bad. Any one know what the cause could be?