Hi, again, It's suppose to be warm here and I have a "weak heat" condition, among other things on a early 98 12 valve. I can hear a change in the blower's pitch when I go from Cold to hot on the heat control, so the mixer door is working. I believe the core has, probably, Bars leak in it, and is partially plugged. I want to back flush the core and would like to know which of the hoses is the hot supply and which is the return? So I can dislodge the obstruction and not put it through the core, some more? I believe the way the coolant flows, on the bottom of the core is where the debris is? I also have a hot wire from the + through a add-on fuse a 20 amp fuse that blows out, I have a 25 in it and seems to be holding for now. How much amps does the blower motor pull on high? And Dodge uses the - to control blower speed? Through the resistors? And blower speed control ****?

 

The coolant line on the drivers side of the truck is the hot input, line on the passenger side is the cold output. Thats the way it is on my 98, I'd imagine the 12v is the same.