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Hi everyone,
I’m new here obviously but I use these forums often for very valuable info related to my LHD 2014 Jaguar XF. I’m having a very benign - yet frustrating issue that’s causing me to pull out whatever hair is remaining on my head - and I’m hoping somehow here can shed some light.
I had an issue recently wherein I noticed that my right side passenger vent was not closing when I turned off the car. But the driver and 2 center vents were closing. This is not a huge deal since I live in the Philippines and ALWAYS have the AC on (climate setting set to auto close, not always open) - so really only noticeable when you shut off the car. Nevertheless, I googled the issue and it seemed like an easy enough fix so I went at it.
Most of the posts I read referred to a small plastic round stepper motor clutch that breaks often so I assumed this would be my case. I removed the RH register (easy enough to remove after two panels) and removed the stepper motor to reveal that it had simply slipped off of the round plastic clutch - slipped off the little inward catch 180 degrees across from the “nipple”. I put it back together and reinstalled it. Only now, it opens and closes as you would expect, but the other 3 registers have remained open now and will not close.
I have done extensive research and testing and learned that all if this should have been done with the climate control setting set to “always open” which I probably did not do. So now I cannot seem to get the other 3 vent registers to join the LIN Bus for communication (I suspect).
To try ti fix, I set the climate control to “always open” and I started / stopped the car twice to confirm settings were stable. Then I disconnected the battery for over an hour. While disconnected, I re-attached the right register. I attached the battery, confirmed all register vents were open and drive the car for a day with the climate setting still on “always open”. I was optimistic that this would work but I just changed the setting back to “auto” and only the right hand register closes when the A/C is turned off OR if the car is turned off. The other 3 vents remain open and will not close.
i understand that I can now leave them on “always open” and this is not an huge deal but I would like to solve this problem as it is consuming me. I’m suspecting I need someway to get the LIN Bus to communicate properly with the other vents not just the RH - which btw is the first in the serial line across the vents in the electrical wiring diagram. I have also tested all pins for voltage, etc.
Any help would be much appreciated! Can’t stop thinking about this now lol.
To add to this in case it helps, while troubleshooting this, I did connect the stepper motor to the car without being attached to the register several times to verify it was working (I suspected the motor was the issue). When connected it definitely tries to initialize itself and find the high/low points which it does not find when it is not attached to the vent with the clutch stops. It does, however initialize itself correctly once the motor is attached to the register with the stops. I’m wondering if this caused some confusion to the Lin bus when the stepper motor was allowed to run past the stops and told the other registers to just remain open. Maybe some DTC’s need to be cleared for it to work? Other the car cycled a few times? Any thoughts would be appreciated I’m out of ideas and may just leave it in “always open” mode now…
A common issue is a faulty pre-heater, this upsets the lin bus & causws issues. Disconnect one of the wires on the pre-heater & test.
Yes I have read this could be the fix too but since one is working now and the other 3 were working before, I assumed this was not the fix. I also had trouble finding that wire. I will research its location and try that and report back. Will do it now…
John,
im going to do this now I think I found where the wire should be. My car is LHD so I’m guessing it’s on the drivers side footwell , right side near the infotainment unit. Will check. But one question - do u think this could be my case if I’ve NEVER used the heater. I live in a very warm climate and only ever used the AC since the car was off the line 9 years ago. Thanks again!
Hey guys. I’m in the car now. It is LHD and I’m under the steering wheel pulling the trim and felt apart but can’t find it. Can anyone point me in the right direction. Where exactly is it and how do I get to it. Want to try to disconnect it.
It's an automatic thing as the engines (diesel) are slow to warm up, I imagine that it's rarely on. Thing I'm not certain of is if the petrol engine cars still have a pre-heater, I'm guessing all the heaters are the same, but I'm not certain of this.
The pre-heater has nothing to do with the AC, more to do with engine temperture & heater demand.
It's an automatic thing as the engines (diesel) are slow to warm up, I imagine that it's rarely on. Thing I'm not certain of is if the petrol engine cars still have a pre-heater, I'm guessing all the heaters are the same, but I'm not certain of this.
The pre-heater has nothing to do with the AC, more to do with engine temperture & heater demand.
But how do I get to it to disconnect it. Summary now is the left three registers now stay open all the time despite the climate setting. They worked fine previously. The right vent, which was removed and reinstalled after aligning the clutch in the only vent working and was previously not working because of the clutch.
There's a youtube search "sofa warrior" (uk account) there's a video showing how to get to it, but it is a R/H/D car & a diesel.
Yes the link is below. I have watched it several times but it lacks the details on how to actually get to that wire. He fast forwards to showing the actual wire but now how he got it, where it was located or what panels to remove to get to it. Any help would be appreciated. I’m stuck.
Yes the link is below. I have watched it several times but it lacks the details on how to actually get to that wire. He fast forwards to showing the actual wire but now how he got it, where it was located or what panels to remove to get to it. Any help would be appreciated. I’m stuck.
Guys are we sure there is actually an electric aux heater on the non-diesel vehicles? My XF is not diesel and I cannot locate this red pre-heater wire.
That said, my issue still persist wherein only the TH register opens / closes. And the other 3 stay open all the time. But they worked before I reconnected the RH register so something is wrong with the communication and needs to be reset? Do I need a special jag diagnostics tool? Could it be that DTC codes need to be cleared first to get it to work?
In the workshop manuals I have the booster heater is only mentioned in relation to diesel vehicles, but I'm not confident it covers 2014 models:
It doesn't usually need any codes clearing to reset it, they just come alive. However if you have SDD it might be able to see if there is a fault in the comms with the registers.
Looking at the LIN network the registers are wired in series, starting with the RH register. If there is a fault, or poor connection, with the electronics in the RH register then LIN signal will not get passed down the chain to the other registers. It could just be a bad connection, so I'd take a look at the connector to the RH register, check the pins aren't bent etc and make sure they are clean. The registers get their open/close commands from a LIN connection to the air mixer (which is also shared with the booster heater, hence why when it fails it mucks up the air vents in the dash). So its possible that there is an issue with that communication, maybe you disturbed the connector or wire looking for the booster heater, so might be worth checking that.
If that doesn't make a difference then maybe remove the RH register and connect the LIN_IN to the LIN-OUT (i.e. bypass the RH register) to see if that makes the other registers work, i.e. the fault is related to the RH register. It could also be a fault with the connection between the outer and inner RH registers, so the next one in line either isn't receiving the signal, or is faulty and not responding to, or relaying, the LIN message.
If you have a tool, computer or oscilloscope that can decode LIN you could connect that at each register starting from the RH side and see if the LIN network is working properly.
I can attest with certainty that my car does NOT have the preheater- but my car is a 2008 build so no guarantee yours doesn't. Pretty sure though they were diesel only, also may not be present in markets outside Europe & US due to climate. I think that is a red herring for your vent problem.
Thank you for your responses and info John, Fivel and Pod XF. I had access to the wiring diagram and had checked the voltages in the supply, lin_in and lin_out pins. I don’t have access to a scope or Lin reader at the moment but the lines all looked good / active w a multimeter (showing 12+ volts and fluctuating on the line lines but I certainly couldn’t capture the ms changes). I also agree that the electric heater is likely not my problem, although I can see in the wiring diagram where it could be if it was attached.
At this point I’m actually thinking the problem is more simpler than I’m making it. I’m thinking that since I didn’t set the climate to always open when I installed the RH register and since I didn’t make sure the register was fully open when I installed it and I hooked up the stepper motor to the system without the register attached (to govern its stop locations), I likely caused the other 3 registers to slip or break off the plastic clutch when the RH register was doing its thing. As punishment for not following the instructions properly, may have fixed one and broken 3 . I’m going to take apart the rest of the dash and look at the other registers to see if they are off track etc. I will report back. This might help someone else in the future as it’s a pretty unique use case. Thanks again!
09-21-2023, 12:10 PM
Odd Issue with Air Registers / Vents
. I’m going to take apart the rest of the dash and look at the other registers to see if they are off track etc. I will report back. This might help someone else in the future as it’s a pretty unique use case. Thanks again!
