Hello,

I just noticed this issue with my truck today. Whenever I turn off the A/C I hear the fan stop, however when the car isn't moving I still feel air coming through the vents. If it's on low I feel cold, if it's on high I feel hot air. The faster I go the more air comes through. Anyone have any idea what could cause this?

I had some dirt and grit in the radiator and around the fan so I very carefully used a pressure washer from a distance to knock some of it out. No fins on the radiator are bent or anything. Besides that, I went on a trail a few days ago with some friends and it was a pretty rough ride (I got jerked around a lot, pulled out of a few bogs).

Thank you guys,
Jacob

 

I may be missing something but in the video the fan is on (at a pretty high speed based on what I see on the front panel) and the climate control is on. So air is moving.

Anyway maybe something is stuck open on yours? If you are sitting still, and the fan is off, air should not be moving through the vents though.

There is a way with the HVAC unit to run a "self test" that will give you error codes. Maybe you should try this:

YouTube Link to HVAC Self

You prob can google any codes you find or search on here to figure it out if you do get error codes.

 

That is with the fan on, as you noticed. I was trying to show the ticking noise I got for a minute but it wasn't very apparent in the video. With the climate control completely off I can feel air coming through the vents, but it's not moving at any significant speed. However, when the climate control off, when I drive quickly (on the highway), the fan stays off, but I feel air rammed through the vents. I read some other threads after a lot of searching, and apparently, it is designed to let air through when moving? Also, apparently, when the A/C is turned off it keeps the positions that it was in before? So if I turn it off in high, is it okay that on the highway I can feel hot air coming through the vents?

 

So, I got 21 and 22, which are sunlight sensor faults. Apparently they occur when the test isn't done in sunlight, so I don't think that's anything to worry about.

I think maybe this is just normal? https://landroverforums.com/forum/di...rol-off-14288/ https://landroverforums.com/forum/di...rol-off-54369/ https://landroverforums.com/forum/di...ng-vent-22139/

 

Some insight on the HVAC operation that you might find helpful (or not...). The heater core always has hot coolant passing thought it and the AC is always ON (unless ECON mode is selected or the HVAC system is turned off). Temperature is controlled by servo vents directing and mixing the hot air over the heater core with cold air from the AC evaporator. Assuming that you are setting the air temp for a "normal" temperature when you turn the system off I believe the servo vents stay where they are. So, if the system is off and you are driving air is being forced though the heater core (which is hot) and being mixed with air from the AC system which is off, so its not cooling down resulting in the mixed air still being quite warm when it's pushed through the vents. Long story short: hot air while moving with the system off is OK. Air is being pushed through the intake which is located under the lower windshield cowling AND there is a vent in the right rear quarter under the trim casing which would draw a tiny vacuum while at speed to ventilate the truck.

To your other point, (air moving through the vents when the truck isn't moving) that I have less of an explanation for. The "fresh air" is technically drawn in from the engine bay (great for acquainting you with those Disco oil leaks) so your radiator fan might be shifting enough air to be pushing some of it through the vents. That's all I can come up with, barring, of course that your fan isn't actually shutting off or there is some sort of super low speed that only the HVAC system can turn on.

Quick thought, if you turn on the "recirculate" setting can you still feel the air moving?

 

With recirculate I still get air while driving, is that meant to happen?

 

I don't think so, there is a servo flap which shuts off the fresh air inlet when recirculating mode is on. Are you absolutely certain the fan motor is off when you switch it off? Like, have you see it with your own eyes? The motor/fan assembly is easy to remove and probably worth removing just to clean it out. Junk gets in there all the time.

The fan is controlled by a relay to turn power on and off and a resistor pack to determine the speed. I suspect it would be easy enough to disconnect the relay to ensure the fan is off to confirm any suspicions.

 

Don't forget that the foam insulation around the servo flaps deteriorates over time. I know little chunks of grey foam have come out of my vents on occasion. With the radio out I've seen more evidence of this behind the dash... I would guess that this would also lead to leaked air getting through the vent system with the climate control completely off.

 

I get hot air through my vents also when driving. I've looked at the flap/air door behind the glove box, and it looks like it closes to me. If my AC wasn't in working order, you wouldn't be able to drive my rig in the summer, it would cook you out.