My Hevac has never been an issue. Today it worked fine, parked up and left the car for 30 mins, on restart no Hevac. Nothing , not one light, no fans just completely dead. I checked all relevant fuses were ok and tried diagnostics with my Icarsoft but it says cannot communicate. Any ideas?
I have removed the Hevac unit just to check for any obvious issues with wiring/plugs. Strangely when unplugged with the ignition on the rear console fan comes on but not when the hevac unit is plugged back in. Do these hevac units just die? 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

I have been doing my best to check the electrics and hopefully, someone with more knowledge can assist if I am on the wrong track.
Following Rave electrical, Fuse 12 provides a constant 12v to the Hevac ECU plug 1630 on a RP coloured wire. This is on page 82 /3 of rave. I have checked this and a constant 12v gets to that plug OK.
Fuse 53 supplies the ignition switch, when the ignition is turned on a live goes to fuse 34 then to plug 1629 on the ecu GY coloured wire. On pin 1 of that plug, GY, I get 12v with the ignition switch on so I presume all the wiring is ok.
As the HEVAC remains totally dead I am now at an end on diagnostics so must guess the Hevac unit is knackered. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

So to end my issues, Unbelievably for Perth Australia, I managed to track down a used Hevac for a very fair price. I was pleasantly surprised that the seller was a Range Rover owner and knowledgeable DIY home mechanic. After telling of my issues he insisted we tried his good unit to prove if mine was, in fact, dead before I committed. The known good Hevac unit lit up with the ignition on and everything proved to work as intended. I enjoyed my hour ride home in air-conditioned comfort. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

looks like this was sorted very quickly wayne...thanks for posting your experience..  ... - .- -.




Y. O. L. O.
.

Glad it is all sorted

Having searched for a related thread to my problem, this one is as close as any, so please forgive me resurecting it again.

2004 Td6 Vogue: On and off over the past two years I have been working on bringing the car back to a healthy state. New inner and outer rear sills and jacking points, complete new hard brake pipes and flexis allround, refurbished rear brakes including new parking brake shoes, new ignition switch, new height sensors, new steering angle sensor, all fluids changed including gearbox etc. Headlights, bcm, bdu, wipers etc etc etc... She now has a brand new shiny MOT but there is still so much to do, and I just want to enjoy driving her again for a while

Trouble now is no HEVAC unit. Completely blank, no lights, no fan nothing. That's for a/c, heater, blowers, windscreen, heated seats etc. It was working fine up until I started to dismantle things, so naturally I have tried to make sure that all relevant items are reconected. I have removed the unit, dismantled and cleaned both pcb's, one of which was practically caked in grim, the part near the fan intake. All fuses are intact. Battery is only 3 years old and has been carefully maintained showing good v at rest and when engine running. Everything else on the car is working normally. There are no codes on my gap IId. So what am I missing? Could the HEVAC unit have gone bad just lying idle and am I going to have to fork out for a replacement unit just to eliminate or prove that possibility? Any thoughts of anything else I could check would be much appreciated. Cheers, Mark