01 9400 A/C problems...still.

Is the APADS showing any flash codes?

 

I don't have access to the actual International APADS diagram, but I do have the generic one. I don't think they use the "air conditioner" relay with an APADS because the relay is for compressor clutch operation with the standard wiring. The apads module powers the clutch itself. I'll start with the blower. The blower has several different circuits for the different speeds including different relays. If you have a failure of any individual circuit you will loose that speed. Generally you will still have one speed or only loose one speed. When you turn on the hvac this triggers relay "heater control". Pin 30 is powered from breaker F1-C, 20amp. This basically powers all speeds except high. High speed comes from "Hi speed" relay, powered by breaker F1-A, 30 amp. The Heater controls get its power from breaker F9-D, 10 amp. Check all those. If still nothing, you may need to open up the heater box and check for power to the motor. If you have power to the motor, the motor has failed.
The 4 flashing red LED is either low or high pressure switch circuit. Basically those sensors are wired straight to the apads module at the 4-wire connector. The low pressure wires at the apads module are White, and White/Black. The high pressure wires are Yellow and Yellow/Black. Do and continuity check between the sensor connector and the apads connector for each wire to see which one is open.

 

Oh, and another thing, check the firewall pass-through connector at the lower left side there that the APADS wires go through. The connector is round and also has the ABS wiring in it. The connector just twists to disconnect. This connector is prone to water intrusion and corrosion of the pins inside.