Dorman 85147 2-Wire A/C High Pressure Switch Instruction Manual

1. Product Overview

The Dorman 85147 is a 2-wire A/C High Pressure Switch designed as a direct replacement for specific automotive applications. This component ensures proper function of the vehicle's air conditioning system by monitoring refrigerant pressure.

This HVAC switch connector is engineered to match the appearance and function of the original hardware, providing reliable performance and durability.

Key Features:

• Direct Replacement: Matches the appearance and function of the factory hardware.
• Ideal Solution: A reliable replacement for a missing or failed original part.
• Durable Construction: Manufactured from quality materials for reliable performance and long service life.
• Quality Assurance: Backed by a team of product experts with extensive automotive experience.
• Vehicle Fitment: Designed for compatibility with select vehicle makes and models.

2. Safety Information

Always prioritize safety when working on vehicle systems. Improper installation or handling of automotive components can lead to injury or damage.

• Disconnect the vehicle's battery before beginning any electrical work.
• Wear appropriate personal protective equipment, including safety glasses and gloves.
• Ensure the vehicle is securely supported if working underneath it.
• If you are unsure about any step, consult a qualified automotive technician.
• Be aware that the A/C system contains pressurized refrigerant. Only qualified personnel should service the refrigerant system.

3. Package Contents

The package for Dorman 85147 typically includes:

• One (1) Dorman 85147 2-Wire A/C High Pressure Switch with integrated connector.

Figure 1: Overview of the Dorman 85147 2-Wire A/C High Pressure Switch.

4. Installation Instructions

This section provides general guidance for installing the Dorman 85147 A/C High Pressure Switch. Specific procedures may vary by vehicle model. Always refer to your vehicle's service manual for detailed instructions.

1. Preparation:
   • Ensure the vehicle's engine is off and cool.
   • Disconnect the negative terminal of the vehicle's battery.
   • Locate the existing A/C high pressure switch on your vehicle. This is typically found on the high-pressure side of the A/C system, often near the condenser or compressor.
2. Refrigerant System Considerations:
   • Important: The A/C system contains pressurized refrigerant. Depending on the vehicle design, the high-pressure switch may be located on a Schrader valve, allowing replacement without discharging the system. However, some systems require the A/C system to be properly discharged and evacuated by a certified technician before removing the switch. Consult your vehicle's service manual or a professional.
3. Removal of Old Switch:
   • Carefully disconnect the electrical connector from the old switch.
   • Using an appropriate wrench, unscrew the old high-pressure switch from its mounting point. Be prepared for a small amount of refrigerant to escape if the system is not fully discharged or if there is no Schrader valve.
4. Installation of New Switch:
   • Apply a small amount of refrigerant-compatible lubricant to the O-ring (if present) on the new Dorman 85147 switch.
   • Thread the new switch into the mounting point by hand to prevent cross-threading.
   • Tighten the switch with a wrench to the manufacturer's specified torque. Do not overtighten.
   • Connect the vehicle's electrical harness to the new Dorman 85147 switch. Ensure a secure connection.
5. Post-Installation:
   • Reconnect the negative terminal of the vehicle's battery.
   • If the A/C system was discharged, it must be properly evacuated and recharged with the correct type and amount of refrigerant by a certified technician.
   • Start the vehicle and test the A/C system for proper operation and check for any leaks.

Figure 2: Close-up view of the 2-wire connector pins on the Dorman 85147 switch, showing the electrical contacts.

Figure 3: Side view of the Dorman 85147 connector, illustrating its profile and wire entry point.

5. Operating Principle

The Dorman 85147 A/C High Pressure Switch functions as a safety and control device within the vehicle's air conditioning system. Its primary role is to monitor the refrigerant pressure on the high-pressure side of the system.

• Over-pressure Protection: If the refrigerant pressure exceeds a predetermined safe limit, the switch will open its electrical circuit. This action typically signals the Powertrain Control Module (PCM) or A/C control unit to disengage the A/C compressor clutch, preventing damage to the compressor and other A/C components due to excessive pressure.
• System Engagement: Conversely, the switch may also play a role in allowing the A/C compressor to engage when pressure is within an acceptable operating range, ensuring there is sufficient refrigerant in the system for proper operation.

Proper operation of this switch is crucial for the longevity and efficiency of the entire A/C system.

6. Maintenance

The Dorman 85147 A/C High Pressure Switch is designed for long-term reliability and typically requires no routine maintenance. However, periodic inspection of the A/C system can help identify potential issues.

• Visual Inspection: Periodically check the switch and its electrical connector for signs of corrosion, damage, or loose connections.
• Leak Detection: If A/C performance degrades, have the system checked for refrigerant leaks, which can affect pressure readings and switch operation.
• System Health: Ensure the overall A/C system is maintained according to your vehicle manufacturer's recommendations.

7. Troubleshooting

If your vehicle's A/C system is not functioning correctly, and you suspect the high-pressure switch, consider the following common issues:

• A/C Compressor Not Engaging:
  • Possible Cause: Low or high refrigerant pressure, faulty high-pressure switch, or electrical issue.
  • Action: Check refrigerant pressure with appropriate gauges. Inspect the switch's electrical connector for corrosion or damage. A faulty switch may prevent the compressor from engaging even with correct pressure.
• A/C System Cycling On and Off Rapidly:
  • Possible Cause: Incorrect refrigerant charge (often low), or a faulty pressure switch providing intermittent signals.
  • Action: Verify refrigerant levels. A diagnostic scan tool may help identify erratic pressure readings from the switch.
• Check Engine Light / Diagnostic Trouble Codes (DTCs):
  • Possible Cause: A malfunctioning pressure switch can trigger specific DTCs related to the A/C system.
  • Action: Use an OBD-II scanner to retrieve any stored codes. Research the codes to determine if they point to the A/C pressure switch or related components.

For complex issues or if you are unable to diagnose the problem, it is recommended to seek assistance from a certified automotive technician.

8. Specifications

9. Warranty and Support

Dorman products are manufactured to high-quality standards. For specific warranty information regarding the Dorman 85147 A/C High Pressure Switch, please refer to the warranty documentation included with your purchase or visit the official Dorman website.

For technical support, installation assistance, or any product-related inquiries, please contact Dorman customer service directly. You can find contact information on the Dorman website or through your product retailer.

Dorman Website: www.dormanproducts.com