This mod as show is for engines not using ISC idle control, and:
(1) gets rid of the relay that another fix uses
(2) does not require cutting ECU wires.

But if a diode is inserted into the cut ELU wire with it's cathode connected to wards the switch (ground) side, and the ground side connected to the fan resistor, I think it will function fine for ISC controlled engines.

 

Could you give a fuller explanation of what you're doing in this diagram and how it works to correct the problem?

 

Since 1999, the PFC does not work 100% of the time in 100% of the cars for A/C activation.
There is a grounding issue with the PFC that is a design problem that does not happend with the stock ecu.
The PFC needs to sense a stronger ground potential then the stock ecu for the A/C to work.

This mod ties the speed 3 & 4 ELU ground to speed 1. Thus only speed 2 has a resitor in its grounding circuit.

The reason to cut or insert a diode into the ELU wire is to prevent a posible reverse current flow fron the ELU to the fan motor +12 volt.

 

So if I have a non functioning A/C due to the power FC this will fix the problem?

 

This is more complex and dificult to do than the fix that uses a new relay inserted into the wiring. But it saves you the price of a few dollars for the relay and long term is more relaible. It is more for the very experienced to do.

It is better for the average person to do the attachment version.

 

Chuck,
Where can I find the other fix using the relay?

Thanks

 

The attachment right above your question.

 

Tried the relay fix today, no go. The compressor won't come on but the PFC shows the A/C is working and I can jump the relay in the front of the car and the A/C blows cold. I'm thinking maybe the relay in the front of the car is bad. I'll try swapping it out next weekend and see if that works.