Remove the Old Core

• 1). Drain the Ion's engine coolant from the water pump (remove the surge tank cap and drain bolt). Disconnect the heater outlet and inlet hoses by removing the clamps.
  
  
• 2). Disconnect the Body Control Module. With the battery disconnected, parking brake on and transmission in Neutral, detach the entire front console, pull back the carpet to the right of the left dashboard support bracket and remove all the BCM's connectors and retainers.
  
  
• 3). Pull back the carpet below the left dashboard support bracket. Remove the gas pedal from the front of the dash, then remove the center floor outlet ducts. Disconnect the main center floor duct from the heater/air conditioner module.
  
  
• 4). Remove the heater core cover, from the HVAC module, sliding it away from the module locating pins and rearwards until the drain tube clears the dash front. Remove the heater core from the cover.
  
  

Install the New Core

• 1). Install the new heater core and reconnect the core cover. Use a new drain tube seal on the drain tube. Spray the core seal and dashmat with soapy water to make installing easier.
  
  
• 2). Reattach the center floor ducts and the gas pedal. Install the Body Control Module and the front console.
  
  
• 3). Connect the outlet and inlet hoses to the heater, replace the surge tank cap, fill the cooling system and connect the negative battery cable.
  
  
• 4). Operate the Ion's engine until it reaches normal operating temperature. Watch over the climate control operation and check for any leaks.