VZ air con issies

[leethal1]

Hello all,

I have had to replace the condenser and reciever dryer on my car, I have re-gassed it with HR-12 (I have an ac license and perfer this gas), The issue I have is that the engine fans seem to switch on when the pressure reaches 230- 250 PSI (the pressure of 134a), does anyone know how to bring the engine fans on at the same time as the compressor? I know that there is a hi press switch just beneath the hi press service point which has 3 wires, can anyone say what they do or have a diagram.

thanks in advance.

Lee

edit - can this be done with tech2?? and to correct title, but not able to be done

[illlusion]

The ecu controls when the fans turn on the high pressure switch is inline with low pressure
Switch for the compressor clutch my fans don't turn on straight away on my adventra about up 10 seconds or so depending on outside temp

[leethal1]

thanks, so it is a switch not a variale reistor? by the wiring diagram - VZ Wiring Diagram HERE:, there is only 1 wire to the ecu, the others go to the maf(confirmed) and the other to the fuel sender(not sure why) hence wiy i thaught one might be power and the other earth to sense pressure, there has to be an over pressure safety cutout somewhere.

only reason i need to know the HR12 pressures are around 35 - 40 on the low side and 130 - 160 high side. the R134 pressure switch is set at 220psi well above this gasses working pressure and the fans cycle very fast as pressure fluctuates (about 3 sec intervals) as it goes from 220psi down to 160 then back up again.

[illlusion]

Yep just a switch to prevent compressor damage in the event of to much pressure or not enough pressure

[leethal1]

Found out it is not a switch, more like a variable resistor to detect low pressure, low fan, high fan and overpressure cutout. Made a box today with a 500K trimpot inside and spliced it into the black/green and white wire at the high pressure switch, took some time to get right but the fans now come on at 175psi and off at 140, so when you are crusing the thermo fans are not on, but when you are stopped at traffic lights fans are on low. also by my calculations I should have gained around 300awhp (from formulation $3 X 100, the gain from each dollar spent as per ebay.)

[RiCeY]

Why do you prefer HR-12?

[leethal1]

Hi RiCeY,
Have used it for a long time, never had a problem with it, no bringbacks, I have 4 empty 9kg containers at home - a commodore only uses 240grams, Have done mostly AU falcons which had a tendancy to split condensers, HR-12 has less head pressure at the compressor - my vz on the trot sits around 135psi, can't really tell the compressor is spinning, as cold as factory as well. I really dont like pag oil too much either, have not heard many good things about it, not operationally but when you come in contact with it, I use ERG500 oil - does not absorb water hence allows the reciever drier to catch water much easier.

On the negitave side it is flammable, never seen an aircon burn thou...

Why do you prefer HR-12?

[illlusion]

Well there u go learn something new every day the diagram I got of the air con system does not show in great detail good to see u got it sorted to