Join Date: Feb 2009
Location: Northeastern BC
No need to be embarrassed here. Last time I checked, everyone puts their pants on one leg at a time ... well, those of us who still have legs. And pants.
If the coolant is low, add a bit into the overflow container (unless it's totally empty, then you'll need to add some to the rad, and then the overflow). Drive it for a day or so, and then check the overflow container to see if it needs some more. The heat/cool cycle of the engine will suck it up from the overflow bottle.
Coolant comes in pre-mixed or add water types. I recommend you get a jug of distilled, de-ionized water from the drug store, not tap water, if you don't use the pre-mixed type. It's cheap. Check your owner's manual for the type of coolant you need. They're not all compatible. If you're totally confused, just buy some from the dealer. I think Prestone and others make pre-mixed coolant that's compatible with all coolants. But definitely check the label and your manual.
Re: your heater not working.
Does the temperature gauge on your dashboard go up to around half-way when the truck has warmed up, and stay there when you're driving? If it's not warming up all the way, then it could be your thermostat is stuck open.
Replacing the thermostat is not expensive, and would be considered a do-it-yourself job, assuming you've got tools and a place to work and inclination. There's lots of information on the net about it. You can't tell if the thermostat is defective just by looking at it (unless it's obviously completely thundered). You have to remove the thermostat housing from the engine, remove the thermostat, and test it.
But if the engine is coming up to temperature properly, and maintaining it as you drive, I wouldn't worry about it just yet. The problem could be elsewhere.
If the engine is warming up properly and you've got enough coolant, a control linkage or something might have become loose, which controls the dampers in the ductwork behind the dashboard. Or it may just need some adjustment. I think the AC/heater dampers work with vacuum motors on these trucks, so a vacuum hose could have come loose.
Also not an impossible job, but if you're a beginner, it could be a bit of a rat's-nest.
It's more unlikely that your heater core would have cacked-out after only two years. Most likely coolant level or thermostat.
If Princess Auto were a real girl, I'd ask her to marry me.