Thread: Nil heat from HEVAC

If it was a long time since the old blend motors failed, the flaps themselves could have become stuck due to non use over an extended period of time, although if they were working fine prior to the failure of the old belnd motors, they might be ok.
Have you tried the ac to see if cold air comes out?
Sometimes the book symbol will not appear for a while even if there is a fault.
I'm assuming the fans are working and the wiring is correct for the new motors.
I would check hevac fuses 8 & 17 as a starting point, they can cause these issues.
If that makes no difference, I'd also check the heater core and hoses to make sure there is not a blockage somewhere.
I would disconnect the heater hoses in the engine bay and give it a flush out with a hose just to make sure that is not the issue.
Even though the heater core is hot, a partial blockage could affect things.
Let me know how that goes!
Cheers, Pete.

Thanks mate. The AC goes great and I have re calibrated the blend door motors with my RSW EAS thingy. Fans are great, ice recently replaced one plus the their relays.

There is definitely hot coolant getting to the core so I'll try flushing the core and see if I unblock anything hiding in there.

If it's not a blockage, it has to be a flap not doing what it's supposed to.
I had a/c only coming out of the passenger side vent and the book symbol appearing on mine. Hooked up the faultmate, and got a right hand blend motor short circuit fault.
Interestingly, I cleared the fault and everything started working again. I have read if the book symbol is showing, the system won't work properly until the fault is cleared.
I was only doing local trips for a couple of weeks and all was fine, but when I did a longer trip, the fault appeard again, and only a/c out of the passenger vent again, same thing with heat.
So mine wouldn't throw a fault until I took it for a longer drive.
If you could get a fault to appear, at least that would point you in the right direction to solving the problem.
Just out of interest, are you mostly doing shorter trips at the moment?

I agree that if the core is hot then it's most likely and issue with the flaps or blend motors. The nanocom lets you operate the motors so you can see what's going on, not sure if you have a nano though.

Steve