mad85 · Nov 8, 2024

noticed a while back that the AC fan is not coming on when I switch on the ac. as far as i know the fan should come on whenever the AC is on, regardless of the temperature (i usually set it to 16 or LO)?

I think it may be an issue with the engine bay fusebox as when i connected the earth from the AC clutch to the FAN the fan is starting. From nanocom I can see that there are some related errors. Any ideas before i remove the fusebox? :

sierrafery · Nov 8, 2024

mad85 said:
as far as i know the fan should come on whenever the AC is on, regardless of the temperature

You dont know far enough

... actually it's not the best setup by LR cos for aircon it should work more that it was designed to based on outside temperature(from 28*C or above), the inside setting has nothing to do with it hence i hacked it to kick in every time the A/C is on otherwise the pressure in the system is always at the upper limit when it's let's say 26*C outside and it kills the compressor in time

though those a/c related open load fault codes can be due to bad contact or "tired" relays... the ECU monitors the relay's coils

mad85 · Nov 8, 2024

sierrafery said:
You dont know far enough ... actually it's not the best setup by LR cos for aircon it should work more that it was designed to based on outside temperature(from 28*C or above), the inside setting has nothing to do with it hence i hacked it to kick in every time the A/C is on otherwise the pressure in the system is always at the upper limit when it's let's say 26*C outside and it kills the compressor in time

though those a/c related open load fault codes can be due to bad contact or "tired" relays... the ECU monitors the relay's coils

ok, thanks for the new information

so the hacking part is ready lol, but i dont like that i have the open circuit errors. im guessing i need to investigate the fusebox a little. is it hard to remove? once tried to remove the internal fusebox and i couldnt get the connectors off no matter how much i tried!

sierrafery · Nov 8, 2024

mad85 said:
i need to investigate the fusebox a little. is it hard to remove?

Wasn't hard for me....but i can remove the interior one too in few minutes.

mad85 · Nov 8, 2024

sierrafery said:
Wasn't hard for me....but i can remove the interior one too in few minutes.

fair enough, effort can be quite relative sometimes

hughdavies · Nov 8, 2024

Does the fan come on at all? these fans are very prone to siezing up, and replacements are not easy to find.

mad85 · Nov 8, 2024

hughdavies said:
Does the fan come on at all? these fans are very prone to siezing up, and replacements are not easy to find.

yes, the fan had been replaced in the past for a Spal one and it does work. I hacked the system a bit by bridging the relay connectors for the clutch and the fan so now it has no choice but to come on whenever there is a request for the ac clutch but am concerned that the errors might indicate corrosion (which might affect other things if left unchecked)

mad85 · Nov 17, 2024

Replaced the engine bay fusebox as it had lots of corrosion and now there arent any errors anymore will still hack the system though so that the fan comes on whenever the ac is on. Was planning to bridge the earth of the two relays unless there is a better method?

sierrafery · Nov 17, 2024

mad85 said:
Was planning to bridge the earth of the two relays

My method was to unplug the external air temp sensor(which is in front behind the grille) then the system's default is to switch the fan on every time the AC is on... that reading was never accurate anyway and i dont need it

mad85 · Friday at 14:28

sierrafery said:
My method was to unplug the external air temp sensor(which is in front behind the grille) then the system's default is to switch the fan on every time the AC is on... that reading was never accurate anyway and i dont need it

i might go this route although i m not a big fan to be honest as i like being able to "brag" when the temperature is showing 44 degrees Celsius on the control lol. If i bridge the earth for the compressor and fan relays, would this engage the compressor if the ecu decides to turn on the AC fan to aid the engine cool? ill be honest this has never happened as the engine only gets a little hot (max i have seen it is 102 degrees celsius) when the AC is on so the compressor would still be engaged then. is my understanding correct?

sierrafery · Friday at 17:53

mad85 said:
If i bridge the earth for the compressor and fan relays, would this engage the compressor if the ecu decides to turn on the AC fan to aid the engine cool?

That's not a good ideea cos the fan will come on together with the compressor on AC compressor request while the fan is supposed to work even with compressor off if the pressure went high in the system but then the compressor will not go off when needed cos it will be activated by the fan request... in a nutshell with bridged relays the fan and compressor will always work together regardless of which one is needed and that's not OK... if you want to keep that useless outside temp reading fit another relay controlled by a thermocouple on the fan relay's coil as to trigger the fan with AC on when the ambient temp is 20* or so, that 28*C is not a good limit IMO cos it happened to me not once that the dual pressure switch disabled the compressor while the fan was off and that's because the condenser wasnt cooled enough .... i can work out a scheme for that if that's what you want

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