Thread: What happened to your Discovery 2 today?

Originally Posted by Eevo

im very confused.

since engine conversion, never been super happy with the aircon, just wasnt cold enough, despite being a big compressor on there.

anyways, had an a/c line blow cause the high pressure was too high. it was borderline high before it blew, so part bad workmanship, part something wrong or design flaw.
replaced condenser with a new one, old one was very gunked up.



now the air from the vents is -1 degrees. (ambient about 12)
great in summer, not good in winter as the evaporator will freeze over, possible compressor damage

there is a TX valve which feeds back to the ECU/BCU to tell the compressor to disengage but with the engine swap and this connected, the compressor never engages as the ECU/BCU is expecting a crank angle input, which is doesnt get, and doesnt engage in the first place.
never had this problem before the condenser was replaced as the evap temps never got this low.

so im a bit stumped

The evap runs below 0° in summer too.

I'll have a look tonight at the control circuit our Romanian mate posted up on another thread, it was pretty sophisticated.
On the mobile/road for the next few hours trying to escape this bloody cold place I'm living in....

Originally Posted by Eevo

im very confused.

since engine conversion, never been super happy with the aircon, just wasnt cold enough, despite being a big compressor on there.

anyways, had an a/c line blow cause the high pressure was too high. it was borderline high before it blew, so part bad workmanship, part something wrong or design flaw.
replaced condenser with a new one, old one was very gunked up.



now the air from the vents is -1 degrees. (ambient about 12)
great in summer, not good in winter as the evaporator will freeze over, possible compressor damage

there is a TX valve which feeds back to the ECU/BCU to tell the compressor to disengage but with the engine swap and this connected, the compressor never engages as the ECU/BCU is expecting a crank angle input, which is doesnt get, and doesnt engage in the first place.
never had this problem before the condenser was replaced as the evap temps never got this low.

so im a bit stumped

The ECU is switching the earth path for the AC compressor and electric fan.
You may need to find the temp sensor input wire that once went to the ECU and use it to control the AC compressor relay directly.
I had to do similar to this for my Defender/D2 hybrid AC wiring.
Do you have RAVE?

C0637-16 YS is the compressor signal wire and C0637 - 38 (31)PW is the signal wire for the electric fan.
If you find the engine running signal wire, you can connect an earth or + (not sure id have to check) and fool the AC ECU into believing the engine is running.

no, its looking for the crank angle sensor.
no input means the engine is off and therefor dont engage the compressor.

Yea I probably havent written that well.
But shouldn't need engine info.ill need to check the V8 diagrams and ECU input/output

OK,, just went through RAVE again and what I did with mine.
The ATC ECU is essentially dumb regarding anything from the engine. It does not look for any signal external to its AC components. Its only (external to AC) inputs it uses is road speed from the BCU to turn off the Aux fan above 80km/h
Which brings us back to the ECU.
The D2 Engine ECU is what grants any Ac compressor or Condenser fan requests. My understanding is you have an LS engine and assume the relevant ECU from that engine?

This comes back to my earlier post where the original connector and sockets mentioned are the request wires from the ATC ECU to the Engine ECU. C0637-16 YS is the compressor request wire and C0637 - 38 PW condenser fan *NB request wires.
If you take these wires and provide them each a relay to operate an earth path to the AC and Fan output , through the old connector output socket and loom C0636-31 and C0637-29 *NB these are the output wires (request granted) or wire direct to AC compressor and Fan relay.
Then any engine running circuit eg fuel pump for power to energise the relays.
The ATC ECU will not know or care and will operate as per factory.

My D2 Chaffy is now up for some drive bits as he dropped 5th gear last night on the way back from Katherine

Chaffy got me home ok .

still had drive in 5th just sounded bloody terrible. Drove home the rest of the way in 4th with no problems at all.

so now looking at some Ashcroft goodness to get Chaffy back on the road.

The wallet is not looking forward to this

Cheers, Chris .

Originally Posted by strangy

OK,, just went through RAVE again and what I did with mine.
The ATC ECU is essentially dumb regarding anything from the engine. It does not look for any signal external to its AC components. Its only (external to AC) inputs it uses is road speed from the BCU to turn off the Aux fan above 80km/h
Which brings us back to the ECU.
The D2 Engine ECU is what grants any Ac compressor or Condenser fan requests. My understanding is you have an LS engine and assume the relevant ECU from that engine?

This comes back to my earlier post where the original connector and sockets mentioned are the request wires from the ATC ECU to the Engine ECU. C0637-16 YS is the compressor request wire and C0637 - 38 PW condenser fan *NB request wires.
If you take these wires and provide them each a relay to operate an earth path to the AC and Fan output , through the old connector output socket and loom C0636-31 and C0637-29 *NB these are the output wires (request granted) or wire direct to AC compressor and Fan relay.
Then any engine running circuit eg fuel pump for power to energise the relays.
The ATC ECU will not know or care and will operate as per factory.

Mark, any idea where are the sensors are to switch the comp ?
Are they in the evap coil or return air ?

Originally Posted by 4runnernomore

My D2 Chaffy is now up for some drive bits as he dropped 5th gear last night on the way back from Katherine

Chaffy got me home ok .

still had drive in 5th just sounded bloody terrible. Drove home the rest of the way in 4th with no problems at all.

so now looking at some Ashcroft goodness to get Chaffy back on the road.

The wallet is not looking forward to this

Cheers, Chris .

I can see the Ashcroft HD bearing in the extension housing fix happening....