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-   -   03 e53 AC problems (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/116320-03-e53-ac-problems.html)

jimdanforth 06-28-2025 08:41 PM

Quote:

Originally Posted by 80stech (Post 1245454)
As already suggested, aux fan not working could be another issue.

I could believe that but I can activate the fan with INPA

80stech 06-28-2025 11:36 PM

I'm not familiar with the non IHKA (auto temp) set up, but it sounds like it's not seeing or liking something. If you can work all the outputs through IMPA but still have no air there must be an input missing.

You could try pulling the lower rad hose temp sensor and see if the DME turns on the aux fan just to see if it has some control of it.

You could also try defrost to see if that kicks the compressor in.

jimdanforth 06-29-2025 06:43 PM

Quote:

Originally Posted by 80stech (Post 1245456)
I'm not familiar with the non IHKA (auto temp) set up, but it sounds like it's not seeing or liking something. If you can work all the outputs through IMPA but still have no air there must be an input missing.

You could try pulling the lower rad hose temp sensor and see if the DME turns on the aux fan just to see if it has some control of it.

You could also try defrost to see if that kicks the compressor in.

I'll try the temp sensor. Did already try defrost. Too hot today to even try

jimdanforth 06-30-2025 06:15 PM

Auxiliary fan does not engage with lower hose temp sensor unplugged, but does when activated in INPA and is speed controllable there.

80stech 06-30-2025 07:32 PM

Well that is interesting. I'm thinking the aux fan maybe doesn't pass the test for the DME but doesn't need to if it gets activated through INPA. Can you read the evap temp in INPA?

jimdanforth 06-30-2025 07:46 PM

Quote:

Originally Posted by 80stech (Post 1245486)
Well that is interesting. I'm thinking the aux fan maybe doesn't pass the test for the DME but doesn't need to if it gets activated through INPA. Can you read the evap temp in INPA?

Don't remember seeing that in INPA, but I cant get into the AC module at all. I kinda assumed it was since I have manual controls

80stech 07-01-2025 08:40 AM

Hopefully someone who knows something about the manual controls will chime in. You should probably get a wiring diagram and theory of operation for the manual controls. It still could be the aux fan but that will be hard to eliminate without having a known good one to plug in.

I see in your first post INPA is showing the A/C input and compressor, that is from the DME then ? Is there even an A/C module ? I know the Evap temp sensor is different for the manual controls so maybe there is not even an A/C module ??

jimdanforth 07-02-2025 01:53 PM

Quote:

Originally Posted by 80stech (Post 1245490)
Hopefully someone who knows something about the manual controls will chime in. You should probably get a wiring diagram and theory of operation for the manual controls. It still could be the aux fan but that will be hard to eliminate without having a known good one to plug in.

I see in your first post INPA is showing the A/C input and compressor, that is from the DME then ? Is there even an A/C module ? I know the Evap temp sensor is different for the manual controls so maybe there is not even an A/C module ??

I think I'll chase the aux fan issue. It's apparently not right anyway and it may be the key to half of this problem. I'll start a fresh thread with details.

80stech 07-04-2025 08:25 PM

When you say there is no voltage at the compressor clutch, have you measured or are you assuming there is no voltage because the clutch doesn't cut in ? Have you tried revving the engine to get the compressor compressing ?

jimdanforth 07-05-2025 12:05 AM

Quote:

Originally Posted by 80stech (Post 1245528)
When you say there is no voltage at the compressor clutch, have you measured or are you assuming there is no voltage because the clutch doesn't cut in ? Have you tried revving the engine to get the compressor compressing ?

I measured it. Pierced the wire and took voltage. It does come up when the INPA turns it on, but not when I request it from the temp selector.
Yes, I did rev the engine to near redline with INPA turning on the compressor, and still no delta on the gauges. Tried without INPA just to cover all options and it still not not engage or change pressure.


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