Heater/defroster problems
Thread Starter
|
Senior Member
Joined: Mar 2018
Posts: 106
Likes: 3
From: California
Heater/defroster problems
I have a 2002 S type. I had a similar problem with my '98 XJ8. When I'm out at night and get back into my car, the windshield is always fogged up no matter what the weather is like outside. So I turn on my defroster which automatically turns on the AC. Okay, maybe that's the way it's suppose to work. Yes, it does eventually defrost the windshield although me and my passengers had to deal with being cold when it was cold outside. So the AC comes on, the fan goes up to high and the windshield clears. Fine. So I turn it off. Meanwhile I'm trying to get some warmth in the car. I turn the heater all the way up. I swear it take over 20 minutes of driving before I feel any hot air. Hey, what's that? The windshield is fogged again. So I go through the defrost / AC / high fan things again. People are cold, fogged up windshield and then I turn it off. This goes on for a long time. Any ideas? Thanks
Veteran Member
Joined: Feb 2018
Posts: 1,797
Likes: 684
From: The wilds of Montana
While Karl ruminates...
Steve: When was the last time that you changed your pollen filter (the one underneath the scuttle in the engine compartment)? If your scuttle drains are not flowing freely, rain/wash water can flow to places it shouldn't and the filter can become sodden, forming a source of moisture being drawn into the HVAC duct-work,
Steve: When was the last time that you changed your pollen filter (the one underneath the scuttle in the engine compartment)? If your scuttle drains are not flowing freely, rain/wash water can flow to places it shouldn't and the filter can become sodden, forming a source of moisture being drawn into the HVAC duct-work,
Senior Member
Joined: Oct 2019
Posts: 233
Likes: 56
From: Central KY. US.
Under the hood on US models..
On the passenger side there is a panel that needs to be removed to replace the cabin air filter.
Last edited by Catfan01; Jan 20, 2020 at 09:04 PM.
Joined: Jan 2012
Posts: 6,067
Likes: 2,982
From: Newport Beach, California
Karl is going to be along in a minute with a list of items for you to check to get the HVAC system diagnosed properly. In the meantime, here is a link to the Workshop Manual for the X200:
https://www.dropbox.com/s/jp6343385h...e_FSM.pdf?dl=0
https://www.dropbox.com/s/jp6343385h...e_FSM.pdf?dl=0
Joined: Mar 2012
Posts: 4,759
Likes: 1,435
From: Hazlet Township, NJ
Check your sunroof drains and ensure they are not clogged up. If windshield is always fogged, especially after rain then you have moisture getting into the cabin.
Same if cabin filter drain is blocked.
Karl will be along shortly regarding HVAC.
Same if cabin filter drain is blocked.
Karl will be along shortly regarding HVAC.
Trending Topics
Veteran Member
Joined: Oct 2012
Posts: 4,895
Likes: 2,303
From: Oregon
Criminy, I guess my reputation precedes me...
Steve, first things first. The #1 cause of windows fogging is leaving previous threads unresolved. Go here and answer the mystery of the missing fuse #18, and whether your car has the early or late wiring:
https://www.jaguarforums.com/forum/s...e-16-a-198995/
Try that before anything else and see if it helps.
Next, be aware there may not be a single magic fix for your defrost issue. It could be a combination of several little things.
As you surmised, it is by design that the AC runs when defrost is selected, or even just when in auto. The AC system helps remove humidity from the cabin. The fogging may come from a combination of too much moisture in the cabin (more details in a minute) and reduced capability to remove it. Basically, the heating system theoretically has a nearly unlimited supply of heat (from the engine) to make the defrost airflow warm (from the heating system) and dry (from the AC system). Reduce the heating capability and you get cold air from the ducts, which even though dry, doesn't work nearly as well.
I would suggest starting with a test of the DCCV as detailed here, in post #2:
https://www.jaguarforums.com/forum/s...ol-how-185002/
Make sure both sides of the DCCV can open and close fully as commanded. After that, move on to post #6 in the same guide, for low or no heat. Please put a thermometer across the defrost duct (don't let it fall in) and let us know what temperature air is coming out of the ducts.
What kind of driving are you doing when this happens? On my '02 V6, I need about 8 minutes of driving at freeway speed before I really feel much heat. When in auto, I think the HVAC system is programmed not to crank up the fan until the coolant temperature is good and hot. No point in blowing lukewarm air, I guess. If you are putzing around town, with that big V8 loafing, there may not be much heat energy in the cooling system to blow into the cabin. I've noticed on my car, the heater performance drops off at idle and is barely adequate. I think the V8 is even worse, which is one reason an auxiliary coolant pump was fitted. Please read this thread for some good troubleshooting tips for a V8 not putting out much heat. Things like a cooling system pressure test, etc. The final fix (note how the OP came back and resolved his thread, hint, hint...) was the aux pump relay had failed, which prevented the pump from running:
https://www.jaguarforums.com/forum/s...roblem-227286/
The previous steps will let you confirm the defrost air is warm. Next, let's make sure the AC system is operating to dry the air. This is a quickie. With the system in Auto, press the DEF button. (This is the windshield defrost, not the heater grid for the rear glass and mirrors.) With the engine at idle, look at the face of the AC compressor pulley. Make sure the pulley face is spinning. If the pulley face is stationary, this means the compressor clutch is not engaged. If that is what you observe, report back and we can walk you through how to troubleshoot that.
If the compressor clutch is spinning, the next possibility is your AC evaporator may be freezing over. A little bit of ice is normal, but too much will restrict airflow and also severely limit the ability of the AC system to remove moisture. Several things you can do here:
1) With the car idling and the AC on, you should see an occasional drip of water on the ground, near the center of the firewall area. This is the evaporator drain. If you see no drip, that can either mean the drain is clogged (more details later) or the evaporator is iced over.
2) Go for a long drive, maybe an hour or so, with the AC on. Park the car on a dry, level spot, somewhere cool. Don't park in a place warmed by the sun, but preferably somewhere in the shade. The idea is you want the ground to be relatively cool so any water draining won't evaporate right away. Come back in about an hour. A small puddle is normal, indicating a little bit of ice has melted. If you see a big puddle (maybe over 12" diameter?), that means there was a lot of ice.
3) If you suspect the evaporator is freezing over, do this: Put your handy dandy pocket thermometer in the center dash vent. First thing in the morning (so no ice is already present), turn on the AC and manually select LO and start driving. If the duct temperature gets below approximately 38F, the evaporator temp sensor is probably reading a little bit high, and letting the evaporator get too cold. After a few minutes, if ice starts to accumulate, the duct temperature will actually rise a little bit due to the ice blocking normal heat transfer. So watch the temperature carefully for those first few minutes.
4) Another possibility for ice accumulation is low refrigerant. If it has been several years since the system was last charged, I bet it is a little bit low. No matter how well the system is sealed, those pesky R134a molecules are great escape artists. The troubleshooting guide has details about recharging if needed.
So far we've made sure you're getting warm air from the heating system. Then we've made sure the AC system has enough capacity to remove normal moisture from the cabin. Now let's look at a few other possibilities for excess moisture in the cabin.
Remove the cabin air filter as described in a previous post. It's kind of a pain to access, so don't even bother with the old one. Just plan to replace it. If the old filter was nasty, that's great. That was likely a big part of the equation, limiting the flow of fresh air. But before installing the new one, let's make sure the HVAC fresh/recirc door is operating properly. If stuck in recirc, you'll never clear out the moisture in the cabin.
You'll need a helper for this check, along with a source of something stinky. You could use a can of nasty air freshener, cigarette smoke, flatulence, etc. Sit in the driver's seat, close all doors and windows. Turn the ignition on (so the HVAC is active), but not to start. Manually set the fan to high, and select Recirc. With the filter still removed, have your helper release the stink where the filter sits. If the recirc door is closed, you really shouldn't smell anything. Maybe just a hint, as the door may not seal 100%. Now turn off Recirc and have your helper release another blast of stink. If the door opens properly, your eyes should water. This is good, as it indicates the fresh/recirc door is opening properly when commanded.
While you have the cabin air filter removed, check for a blocked drain. Working from potentially faulty memory, I'm pretty sure there's a drain for rainwater at the bottom of the filter housing, designed to dump any water overboard before it can drawn into the rest of the ductwork. If so (can anybody verify?), make sure this drain is open. If it's arranged like I'm thinking, you should be able to pour a little bit of water in there and you'll see it run out onto the ground.
If equipped with a sunroof, check those drains, too. Anybody got any ideas there?
So there, is that enough for ya? The rest of you guys satisfied? Was it worth the wait?
Steve, first things first. The #1 cause of windows fogging is leaving previous threads unresolved. Go here and answer the mystery of the missing fuse #18, and whether your car has the early or late wiring:
https://www.jaguarforums.com/forum/s...e-16-a-198995/
Try that before anything else and see if it helps.
Next, be aware there may not be a single magic fix for your defrost issue. It could be a combination of several little things.
As you surmised, it is by design that the AC runs when defrost is selected, or even just when in auto. The AC system helps remove humidity from the cabin. The fogging may come from a combination of too much moisture in the cabin (more details in a minute) and reduced capability to remove it. Basically, the heating system theoretically has a nearly unlimited supply of heat (from the engine) to make the defrost airflow warm (from the heating system) and dry (from the AC system). Reduce the heating capability and you get cold air from the ducts, which even though dry, doesn't work nearly as well.
I would suggest starting with a test of the DCCV as detailed here, in post #2:
https://www.jaguarforums.com/forum/s...ol-how-185002/
Make sure both sides of the DCCV can open and close fully as commanded. After that, move on to post #6 in the same guide, for low or no heat. Please put a thermometer across the defrost duct (don't let it fall in) and let us know what temperature air is coming out of the ducts.
What kind of driving are you doing when this happens? On my '02 V6, I need about 8 minutes of driving at freeway speed before I really feel much heat. When in auto, I think the HVAC system is programmed not to crank up the fan until the coolant temperature is good and hot. No point in blowing lukewarm air, I guess. If you are putzing around town, with that big V8 loafing, there may not be much heat energy in the cooling system to blow into the cabin. I've noticed on my car, the heater performance drops off at idle and is barely adequate. I think the V8 is even worse, which is one reason an auxiliary coolant pump was fitted. Please read this thread for some good troubleshooting tips for a V8 not putting out much heat. Things like a cooling system pressure test, etc. The final fix (note how the OP came back and resolved his thread, hint, hint...) was the aux pump relay had failed, which prevented the pump from running:
https://www.jaguarforums.com/forum/s...roblem-227286/
The previous steps will let you confirm the defrost air is warm. Next, let's make sure the AC system is operating to dry the air. This is a quickie. With the system in Auto, press the DEF button. (This is the windshield defrost, not the heater grid for the rear glass and mirrors.) With the engine at idle, look at the face of the AC compressor pulley. Make sure the pulley face is spinning. If the pulley face is stationary, this means the compressor clutch is not engaged. If that is what you observe, report back and we can walk you through how to troubleshoot that.
If the compressor clutch is spinning, the next possibility is your AC evaporator may be freezing over. A little bit of ice is normal, but too much will restrict airflow and also severely limit the ability of the AC system to remove moisture. Several things you can do here:
1) With the car idling and the AC on, you should see an occasional drip of water on the ground, near the center of the firewall area. This is the evaporator drain. If you see no drip, that can either mean the drain is clogged (more details later) or the evaporator is iced over.
2) Go for a long drive, maybe an hour or so, with the AC on. Park the car on a dry, level spot, somewhere cool. Don't park in a place warmed by the sun, but preferably somewhere in the shade. The idea is you want the ground to be relatively cool so any water draining won't evaporate right away. Come back in about an hour. A small puddle is normal, indicating a little bit of ice has melted. If you see a big puddle (maybe over 12" diameter?), that means there was a lot of ice.
3) If you suspect the evaporator is freezing over, do this: Put your handy dandy pocket thermometer in the center dash vent. First thing in the morning (so no ice is already present), turn on the AC and manually select LO and start driving. If the duct temperature gets below approximately 38F, the evaporator temp sensor is probably reading a little bit high, and letting the evaporator get too cold. After a few minutes, if ice starts to accumulate, the duct temperature will actually rise a little bit due to the ice blocking normal heat transfer. So watch the temperature carefully for those first few minutes.
4) Another possibility for ice accumulation is low refrigerant. If it has been several years since the system was last charged, I bet it is a little bit low. No matter how well the system is sealed, those pesky R134a molecules are great escape artists. The troubleshooting guide has details about recharging if needed.
So far we've made sure you're getting warm air from the heating system. Then we've made sure the AC system has enough capacity to remove normal moisture from the cabin. Now let's look at a few other possibilities for excess moisture in the cabin.
Remove the cabin air filter as described in a previous post. It's kind of a pain to access, so don't even bother with the old one. Just plan to replace it. If the old filter was nasty, that's great. That was likely a big part of the equation, limiting the flow of fresh air. But before installing the new one, let's make sure the HVAC fresh/recirc door is operating properly. If stuck in recirc, you'll never clear out the moisture in the cabin.
You'll need a helper for this check, along with a source of something stinky. You could use a can of nasty air freshener, cigarette smoke, flatulence, etc. Sit in the driver's seat, close all doors and windows. Turn the ignition on (so the HVAC is active), but not to start. Manually set the fan to high, and select Recirc. With the filter still removed, have your helper release the stink where the filter sits. If the recirc door is closed, you really shouldn't smell anything. Maybe just a hint, as the door may not seal 100%. Now turn off Recirc and have your helper release another blast of stink. If the door opens properly, your eyes should water. This is good, as it indicates the fresh/recirc door is opening properly when commanded.
While you have the cabin air filter removed, check for a blocked drain. Working from potentially faulty memory, I'm pretty sure there's a drain for rainwater at the bottom of the filter housing, designed to dump any water overboard before it can drawn into the rest of the ductwork. If so (can anybody verify?), make sure this drain is open. If it's arranged like I'm thinking, you should be able to pour a little bit of water in there and you'll see it run out onto the ground.
If equipped with a sunroof, check those drains, too. Anybody got any ideas there?
So there, is that enough for ya? The rest of you guys satisfied? Was it worth the wait?
Last edited by kr98664; Jan 21, 2020 at 11:35 AM.
Member
Joined: Aug 2017
Posts: 91
Likes: 17
From: Suffolk, UK
[QUOTE=kr98664;2181406]Criminy, I guess my reputation precedes me...
Steve, first things first. The #1 cause of windows fogging is leaving previous threads unresolved. Go here and answer the mystery of the missing fuse #18, and whether your car has the early or late wiring:
https://www.jaguarforums.com/forum/s...e-16-a-198995/
Karl...thanks for sharing that. Its a similar problem to what i have with fogging of windows when i first get in it...can't see any leaks even from a coolant pressure test, so suspect its something else as you have suggested.
Also....(apologies for hijacking the thread) Karl this one is for you...my car friends now affectionately refer to my car by asking: how's the buttocks sensor doing?
....who needs the comedy channel when you have banter like this!!! Good to read
Steve, first things first. The #1 cause of windows fogging is leaving previous threads unresolved. Go here and answer the mystery of the missing fuse #18, and whether your car has the early or late wiring:
https://www.jaguarforums.com/forum/s...e-16-a-198995/
Karl...thanks for sharing that. Its a similar problem to what i have with fogging of windows when i first get in it...can't see any leaks even from a coolant pressure test, so suspect its something else as you have suggested.
Also....(apologies for hijacking the thread) Karl this one is for you...my car friends now affectionately refer to my car by asking: how's the buttocks sensor doing?
....who needs the comedy channel when you have banter like this!!! Good to read
Last edited by beulahjag; Jan 23, 2020 at 09:41 AM.
Veteran Member
Joined: Oct 2012
Posts: 4,895
Likes: 2,303
From: Oregon
Well, technically, I don't think it's possible to hijack a thread if the OP abandons it. I guess from now on, that will be known as "Pulling a Steve". Dang, I was looking forward to what the fix might be. I put about two hours' worth of research into my previous reply. Maybe I can get Steve to come do an equivalent amount of yard work at my house to even things up. 
Veteran Member
Joined: Oct 2012
Posts: 4,895
Likes: 2,303
From: Oregon
I don't know if "wrong" is the most appropriate term, but you pulled a Steve. You started a thread by asking a detailed question, get some good in-depth replies, and then crickets. I figured you had given up on us. No response at all until I pulled your chain a little.
I've got some rose bushes that need pruning. Or just some general raking and debris cleanup if you'd prefer that.
I've got some rose bushes that need pruning. Or just some general raking and debris cleanup if you'd prefer that.
Senior Member
Joined: Oct 2019
Posts: 233
Likes: 56
From: Central KY. US.
Steve-
I've only been here a couple of months and I've seen plenty of drive by members that post an issue and have never come back to let these guys know what actually fixed the problem. Looking back at the 100+ post issue Karl jokingly referred to is maybe an example of what they see?
I'm sure nobody wants you to become a "verb" here. I did read the entire thread about the missing fuse 18...Lots of free time and energy went into trying to get you back on the road then..crickets.
I don't want to begin to list the forum subscribers and members that have helped me so far because I would leave someone out.
If "wrong" is the incorrect word? Help us all by closing issues so the forum can use that data moving forward..
JMHO
I've only been here a couple of months and I've seen plenty of drive by members that post an issue and have never come back to let these guys know what actually fixed the problem. Looking back at the 100+ post issue Karl jokingly referred to is maybe an example of what they see?
I'm sure nobody wants you to become a "verb" here. I did read the entire thread about the missing fuse 18...Lots of free time and energy went into trying to get you back on the road then..crickets.
I don't want to begin to list the forum subscribers and members that have helped me so far because I would leave someone out.
If "wrong" is the incorrect word? Help us all by closing issues so the forum can use that data moving forward..
JMHO
Last edited by Catfan01; Jan 24, 2020 at 07:39 PM.
Thread Starter
|
Senior Member
Joined: Mar 2018
Posts: 106
Likes: 3
From: California
Let me start by saying that I fully appreciate (LOVE) all of the help from all of you in here when it comes to technical advice. BUT>>> I don't deal with any of my car issues until the weekends and some weekends are just too busy otherwise to work on cars muchless even turn on my computer. So today I'm reading all of this advice and going to go out and start looking around for some of the potential problems you all pointed out. THANK YOU TIMES INFINITY. I didn't know that it was appropriate to answer threads right away. I'm VERY thankful. Now, off to get greasy.
Thread Starter
|
Senior Member
Joined: Mar 2018
Posts: 106
Likes: 3
From: California
Something tells me I'm using this forum wrong. I don't mean to. Thank-you for your input. I'll let you know when I solve this issue and what it was. That is if I ever solve it. I've got an intensely busy life and a fogged up windshield on my weekend driver isn't always on the top of my list however it is quite important. Thank you so much for your help ! !
Steve
Steve
Member
Joined: Aug 2017
Posts: 91
Likes: 17
From: Suffolk, UK
Hi Steve, I don't believe you are using it wrongly....most folks on the forum are enthusiasts (maybe even full time professional mechanics) with a problem or have a genuine passion or both.... to help keep their motors running. They as i do are genuinely keen to know what-how-when-if a problem was solved. This forum and indeed other forums like this one (I also run a Land Rover Discovery) are totally invaluable to the aforementioned when it comes to taking control and fixing things yourself, if you have time, and a few tools, with a good sense of humor , some ambition to have a go,.... not necessarily in that order!
As i have a similar problem although to yours, (fogging up) i'm hopeful i can share the cause and solution....and if i find mine first ,you'll be the first to know.
Im going to hook up my pressure tester again and try once more next weekend. I dont think it'll reveal much as im not loosing anything noticeable from the header tank...I haven't added anything for 8 months...and not since new radiator and header tank.
btw, as its too cold and dark when work work is over each day, I only get to my car at weekends and that is only if something must be done.
Best
Stuart
As i have a similar problem although to yours, (fogging up) i'm hopeful i can share the cause and solution....and if i find mine first ,you'll be the first to know.
Im going to hook up my pressure tester again and try once more next weekend. I dont think it'll reveal much as im not loosing anything noticeable from the header tank...I haven't added anything for 8 months...and not since new radiator and header tank.
btw, as its too cold and dark when work work is over each day, I only get to my car at weekends and that is only if something must be done.
Best
Stuart
Thread
Thread Starter
Forum
Replies
Last Post
1999 VANDEN PLAS
XJ XJ6 / XJ8 / XJR ( X350 & X358 )
2
Nov 15, 2018 05:31 AM
Blue Lion
S-Type / S type R Supercharged V8 ( X200 )
1
Aug 10, 2011 03:13 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)