1. Disconnect the negative terminal of the battery to avoid any electrical accidents.
2. Locate the heater matrix housing inside the vehicle. It is usually situated behind the dashboard or in the engine compartment near the firewall. In the Relay ambulance, it's most likely behind the dashboard.
3. Remove the necessary parts, such as the dashboard or the engine components, to access the heater matrix housing.
4. Identify the inlet and outlet pipes connected to the heater matrix. Disconnect these pipes by loosening the hose clamps or fittings.
5. Remove the mounting bolts or screws that secure the heater matrix in place.
6. Carefully slide out the old heater matrix from the housing.
7. Inspect the condition of the housing and make sure it's clean and free of any debris. If there is any damage or excessive corrosion, it might be necessary to replace the entire housing as well.
8. Position the new heater matrix inside the housing and align it properly.
9. Reattach the inlet and outlet pipes and tighten the hose clamps or fittings.
10. Reinstall the mounting bolts or screws to secure the heater matrix in place.
11. Reconnect any electrical connectors or sensors related to the heater matrix.
12. Reinstall the removed components, such as the dashboard or engine parts.
13. Reconnect the negative terminal of the battery.
14. Test the heater system by turning on the engine and setting the climate control to heat. Make sure you have warm air coming through the vents.
It is important to note that this process can vary depending on the exact year and model of your Relay ambulance. If you encounter any difficulties or feel uncertain about the replacement, it's best to consult a professional mechanic or refer to the specific service manual for your vehicle.
