* Rear AC Blower Motor: This is the most common reason. It's a separate motor located in the rear of the van. It could have burned out, failed due to a short, or have a faulty connection.
* Rear AC Blower Motor Resistor: This regulates the fan speed. A failed resistor can prevent the blower from working at all.
* Rear AC Control Panel/Switch: A problem with the switch or the wiring to it could prevent the rear system from activating.
* Wiring and Connections: A loose, corroded, or broken wire somewhere in the circuit leading to the rear AC components is a possibility. This is more likely if something was recently modified or repaired in the van.
* Blend Door Actuator (Less Likely): While less probable since the front works, a faulty actuator controlling airflow direction *could* prevent air from reaching the rear vents. This is more common if you've experienced issues with air direction even when the front AC is on.
Fuse Location: Unfortunately, there isn't a single "rear AC fuse". The system likely shares some fuses with the front system for common components (like the compressor). You'll need to consult your owner's manual. It will have a fuse box diagram showing the locations of all fuses and what they protect. There might be multiple fuse boxes in your E-350, one under the hood and potentially one inside the passenger compartment.
Troubleshooting Steps:
1. Check the Owner's Manual: Find the fuse box diagrams and check any fuses related to the AC system or the rear blower motor. Replace any blown fuses.
2. Listen for the Rear Blower Motor: With the rear AC switched on, listen carefully near the rear vents. Can you hear any clicking or whirring from the blower motor? If not, it is likely the culprit.
3. Check the Rear AC Controls: Ensure the rear AC controls are correctly set and functioning.
4. Visual Inspection (if comfortable): If you're mechanically inclined, you might try to access the rear blower motor (often under the rear seat or in the rear wall). Look for any obvious damage to the wiring or the motor itself. *Caution: Disconnect the battery's negative terminal before working with electrical components.*
5. Professional Diagnosis: If you can't find the problem after these steps, it's best to take your van to a qualified mechanic specializing in automotive AC systems. They have the tools and experience to diagnose and repair the issue efficiently.
Remember safety first. Working with automotive electrical systems can be dangerous if you're not familiar with the procedures. If you're unsure about anything, it's always best to consult a professional.
