How to Troubleshoot a Toyota T100 A/C

Troubleshoot the A/C system in your Toyota T100 before temperatures rise into the double-digits this summer. There are a number of things that can go wrong with the A/C system, whether it's an issue with insufficient A/C pressure or a fuse that has blown. Before taking your Toyota T100 into the shop for what could turn out to be an expensive repair, there are a few troubleshooting steps you can run through on your own.

Difficulty:

Moderately Easy

Instructions

1. • 1

     Start the engine and turn on the A/C and fan to check if the A/C controls are faulty. If the controls are difficult to move or loose, have them replaced. If the fan does not turn on, a fuse may have blown, or the fan itself could be faulty.

   • 2

     Check the fuse box for blown fuses. The fuse box is located on the left side next to the foot pedal. Consult the schematic on the inside of the fuse box cover to locate the fuse for the A/C system. If the thin metal strip inside the fuse is broken, replace it with another of the same rating.

   • 3

     Start the engine and look under the hood to check the two heater hoses. The heater hoses protrude from the firewall and are roughly the thickness of a garden hose. The firewall is the metal division that separates the engine and passenger compartments. Place your hand on the two heater hoses. They should both be warm to the touch. However, one should be slightly cooler than the other. If it is not, it could mean that the valve control needs to be replaced. Have a qualified mechanic investigate this further for you.

   • 4

     Set the A/C to the highest setting with the engine running. Check under the hood to see if the magnetic clutch connected to the A/C compressor engages. If it does not turn over, this could mean that the system is low on refrigerant. Have a mechanic refill the system. If the magnetic clutch is receiving voltage but is not engaging the compressor, the clutch may be defective and need to be replaced.

   • 5

     Inspect the A/C hoses for leaks. If you notice a green, oily residue on the hoses, they may need to be replaced.

   • 6

     Turn the engine off and test the A/C system for sufficient pressure. Remove the black caps from the service ports on the Toyota T100's A/C unit. Screw the blue hose to the low-side service port and the red hose to the high-side port. The test gauge has both a red pressure monitor and a blue monitor. The pressure should read between 50 and 80 PSI. If it does not, it could indicate a leak. Have a mechanic investigate it further for you.