Check to make sure both heater hoses are hot when engine warm. Check for a vacuum leak. If it has a water valve on heater hose or engine it must have vacuum to send hot water to heater. Also, must have for switching from defrost to floor. We do not have vacuum charts for that truck due to age. But start at engine and should go back to heater through firewall to control on dash then to vacuum motors on heater. Also, check for a broken heater cable if you have one I forget on that model.
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Sunday, January 15th, 2017 AT 11:10 AM