why would the heater on ford ranger go out
Low coolant level, stuck open thermostat, etc.
your automobile has had it my son could be a blown headgasket, check for back pressure on the cooling system on cold start.
Tom has a good point, but also there is a vacuum operated valve in-line on the heater core supply hose that can become stuck or vacuum line detach. I'm not sure what year this is, I think 1999 but will be similar or same, it is Ranger
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