I've been trying to tackle the issue with AC in my 2003 540i.
I've looked at numerous threads and videos about diagnosing my issue.
Here's what's happening:
Here's what I've done so far:
What other issues can be wrong with the AC system? Does a clogged/stuck compressor prevent the car from turning the AUX fan on?
I've looked at numerous threads and videos about diagnosing my issue.
Here's what's happening:
- The AC function appears to activate: I notice there's a bit more airflow when AC button is activated.
- AUX fan does not turn on regardless of car's temp or AC is on or off.
- AC clutch does not activate when AC button is pressed.
- External temp sensor was replaced and shows proper outside temp.
- AUX fan is not seized, can be rotated easily
Here's what I've done so far:
- Tested AC clutch with direct 12V - clutch activates (can hear it click).
- Tested the lead to AC clutch but is only at 5V regardless of AC being on or off
- Tested (was good) and swapped out lower radiator temp sensor (AKA AUX fan switch) - AUX fan still does not turn on.
- Checked leads and plug to AUX fan, it gets constant 12V at plug but does not seem to activate fan; third wire has 5V going to it (I assume this wire sends the signal to the fan's "CPU" to turn it on).
- Checked AC charge and recharged it to 40psi.
- Checked blower fuses 75 and 76. Checked all AC related fuses in glove box (9, 20, 7, 20, 22, 23)
What other issues can be wrong with the AC system? Does a clogged/stuck compressor prevent the car from turning the AUX fan on?