How to Recharge a Mercedes Benz Auto Air Conditioner

1. Open your hood and locate the high and low pressure ports of your air conditioning system. These ports are located on two pipes that are attached to your condenser and are marked with an "H" or an "L" on their caps to identify which is which (high and low, respectively).
2. Remove the cap on the low side and connect the blue gauge to the port. You can remove the cap by unscrewing it by hand, then screwing the blue hose onto the port.
3. Remove the cap on the high side and connect the red gauge to the port. You can remove the cap by unscrewing it by hand, the screwing the red hose onto the port.
4. Record the PSI readings on the gauges and compare them to the recommended PSI ratings for your AC system in your owners manual.
5. Connect a refrigerant can to the yellow hose on your AC gauges and allow it to charge the system. Continue filling until the blue gauge reaches the same PSI as recommended in the owners manual.
6. Disconnect the refrigerant can, then remove the red hose, and finally disconnect the blue hose.
7. Screw the caps back onto the high and low ports.