406 HDI Cabin blower problem

Hi,

Hope you can help.

Here is the problem:

My A/C would not work when the car was holding still at an traffic light, I
found that the engine fan motor was 120% dead, changed it with a new unit and
also changed the Low speed fan relay, High speed relay and the Cooling relay.
Now during testing the new engine fan ran also when the cars engine is
running in idle, and the A/C worked 100%.

The next morning I took the car for a spin, and the A/C was on AUTO and
working, suddenly the cabin blower stopped running (and it has not run since).


I then checked and tested all fuses in the passenger and engine fuse box,
nothing wrong. I noticed that after this the A/C would not turn on, when I
pressed the A/C ON button, I did not hear the “Click” sound of the A/C
compressor coming on. I the un mounted the cabin blower, and connected it to
a 12 Volt battery, and it ran fine.

When the cabin blower is installed in the car, its DC supplied from a little
black box (control module), near the heat matrix. The box is then supplied
from the 12 volt main battery, when I measured the output from this box with
the blower disconnected (and the cars engine running, with A/C on), my multi
meter said app. 12 Volts, but with the blower connected it said app. 0 Volt.
Also with the blower disconnected I could hear the A/C compressor giving me
the “click” ON sound, and I could switch the A/C OFF and ON without problems,
but with the blower connected noting would work, not the blower the A/C
compressor or the engine fan.

I suspect that the cabin blower control module is defect, but it was working
fine before I installed the new engine fan motor, and relays. I have
disconnected the engine fan to see if this made the cabin blower work again,
but no.

Why does the cabin blower control module control my A/C compressor?

Or is it the A/C control unit in the car that is dead?

Can anyone please help with advice?

Br. TIH

 

Hi,

Can anyone Help?

BR:
TIH

 

Problem solved, I installed another control box.