Vn v8 no vaccume to heater tap plz help

[MikeC]

Checked everything tested everything. Still no luck heater core is hot hoses are hot still won’t blow hot air it’s got me stumped

Is the hot water valve opening and closing? If you clamp it open, put the temp on max (32C ?) and override the fan speed to 3 does the heater blow hot air?

 

[Lex]

Checked everything tested everything. Still no luck heater core is hot hoses are hot still won’t blow hot air it’s got me stumped

Checked the condenser (the one in front of the radiator?), do you have air flow, or jambed up with leaves & crap.?

 

[Fu Manchu]

Wouldn’t be the first time a new part is faulty.

Have you got a vacuum pump to test the lines?

 

[MikeC]

I live near Heathcote and I bet its cold at the moment. First thing I'd do is turn the heater right up on the CC then check that the heater valve opens and the pipes to the heater core get hot.

My heater used to only work on full 32 deg heating- that was a stuck motor/limit switch on the mixer door- the control is on the passenger side of the heater box.

Then later it stopped heating- that was the stuck heater valve.

With the CC computer it is better to start with the obvious and easily checked then work back. That computer needs a a few different inputs to be right before it opens the heater valve.

 

[Gmvn5l]

Is the hot water valve opening and closing? If you clamp it open, put the temp on max (32C ?) and override the fan speed to 3 does the heater blow hot air?

Still blows cold

 

[Gmvn5l]

I live near Heathcote and I bet its cold at the moment. First thing I'd do is turn the heater right up on the CC then check that the heater valve opens and the pipes to the heater core get hot.

My heater used to only work on full 32 deg heating- that was a stuck motor/limit switch on the mixer door- the control is on the passenger side of the heater box.

Then later it stopped heating- that was the stuck heater valve.

With the CC computer it is better to start with the obvious and easily checked then work back. That computer needs a a few different inputs to be right before it opens the heater valve.

The amb is showing -30 not sure why.
I converterd the whole car to full electrics cruise and climate controll. Swapped out the whole loom and heater box.
I checked all the vaccume valves they all open and close and hood vaccume. Just can’t seem to blow hot air no matter what I do

 

[Gmvn5l]

Checked the condenser (the one in front of the radiator?), do you have air flow, or jambed up with leaves & crap.?

condenser u mean the radiator thing? if so it’s not clogged with leaves as I had the whole car stripped. Due to building it

 

[Gmvn5l]

Wouldn’t be the first time a new part is faulty.

Have you got a vacuum pump to test the lines?

No vaccume pump but I did test the lines with air there’s no blockage. I do know that the line to heater tap I can suck threw it. iv replaced the bottom vaccume block under radio and still can do that same thing

 

[Gmvn5l]

New core! Getting serious.
Make sure you have a good heater tap- I had an opening failure until I threw out the replacement supposedly GMH tap and installed a Gates.
After that you may have a control system problem.
Check the wiring and connections to the solenoid pack at the back of the radio as much as you can.Check for creased or damaged hoses.The heater water valve hose is yellow and the vacuum source hose is black
Have you run through the self diagnosis program on the climate control. It's detailed on the forum but basically you start by pressing the CC off button within 10 secs of switching the ignition on. Push the hot button each time the CC finishes testing to start testing the next group of control software/sensors.

When you get to modes you should have :
step-Valve state
31-closed
32-closed
33-open
34-open
35-open

If you can check the heater valve solenoid it should have 12V when the valve is closed.

Codes where 21 and 25

 

[MikeC]

Code 21 and -30 deg C is an open circuit on the ambient temperature sensor you would have installed in front or the radiator.

25 is an open circuit on the sun sensor in the top of the dashboard.

I don't know if the CC works if the inputs from these sensors is missing.