Should be around the top hose by the engine right? Thats where mine is anyways.
BTW i don't think you mentioned it but what year is it?

 

Its a 1990 I found the sensor ran out of time to check it been trying to figure out why I don't have heat. I've replaced the vacume switch on the side if the heat ac controls put a new blower motor in just because the old one was blowing week checked for vacume leaks and the only one was on the switch that I switched out with another one I guess next is a new heater core

 

Yup heater core would be my next guess. It is probably clogged, that seems to happen often.

 

Ok this might be a stupid question, but can you flush it some how or do you just have to replace it?

 

I think the best way to flush just the core would be to take it out and pump water in via garden hose. Thats what i would try before buying one, thats if you can remove it easily. If not you could probably do it while it is on the truck just unhook one hose from the core and either hook another hose on the other side or take both hoses off and fire a garden hose with full blast into it.

 

But the good news is it is not blowing as cold as it was but its not as hot as it should be either its somewhere between cold and warm. Also do the defrost vent pipes get cloged as well there's hardly any air the blows from there?

 

I would assume they would get clogged, people leave stuff on the dash and it can get dropped into the vent tube. If you can get to the side where it goes into the blower housing try using an airgun and shooting up into it. That may dislodge whatever is blocking it. I don't know too much about the air vent systems cause i haven't had much work to do on them but that seems like it would work.

 

Ok thanks ill try that with the water hose and the air hose.

 

Ok, good luck.