So in 1 of my vehicles, I have what is essentially a 2012 late model VE commodore E38 & 6L80 transmission in a 2002 Holden VY ute & I had 2 problems. 1- I was unable to control the AC through the factory dash button & 2 I had no automatic functioning reverse lights. For a while i got around this by having them on manual switches, but since I want everything to work as if it was factory I started looking into a solution.

Since i had been playing around with the VZ platform already & getting the 6L80 to work with the same ECM/TCM architecture, I took another look at these functions & how they were configured & thus managed to work out how to control the Aircon Compressor & Reverse lights in the later OS by manipulating the Can settings to send the correct data to the VZ PIM module.

For a bit of background info, AC Compressor Control in a factory vy ls1 is controlled by the ecu & is part of the engine harness, however the request to turn it on/off comes via a button on the climate control panel, which is wired to the BCM which talks to the original PIM via UART protocol, which gets translated to the VPW protocol to the ECU. The reason for being wired to the ECU is mostly to disengage the compressor based on AC pressure & or RPM.

On the E38 AC control is similar in that it’s wired to the ECU, but the request needs to be communicated to it via the CAN Bus, luckily Holden has already done the engineering for this in the VZ model, so it was just a matter of wiring in a VZ PIM and programming it with the right options via a Tech2, then having the ECU configured to listen & transmit the right can data.

Having mapped out all the CAN ID’s for the early VZ ecu OS it was just a matter of doing a comparison against the later OS & turning the TX & RX ID’s on, in this case it was RX ID 380 & TX ID 348.

Next up was the reverse lights because unlike the 4 speed controllers which have the reverse light power wired via the Park Neutral Safety switch on the side of the box. The 6L80 is all through CAN & since the VZ PIM can be setup to ground an output when it receives the reverse signal it was just a matter of having the TCM send the correct ID – 320.

End result is the AC compressor kicks on/off when the dash button is pressed & with the help of a relay wired in & using the ground activation from the PIM I get reverse lights too.