Where can you get an original diagram of the heating cooling system of a 1990 dodge b250 ram van bought this used and lines have been cut and now the blower will not blow any heat?
There are only two coolant lines going to the heater. Inlet & outlet. They may be slightly different sizes, so connect them accordingly. If they are the same size then it usually does not matter which is inlet and which is outlet. But ask yourself, why are they disconnected. More than likely the heater core is leaking and needs replacing, so be aware of that and watch for leaks inside the vehicle, passenger side.