HVAC Mode Door Problem

[@nohalo1103]

Somebody is not paying this man enough money he is an awesome instructor very talented the way he explains the whole procedure where almost anyone can understand very impressive

[@strokewarrior5762]

Thank you Danny. I appreciate you recognizing the educational benefit

[@fgarcia5446]

Agree 💯 %

[@truthnewsstation2698]

What if my compressor turns on and fan but not cold and shoots thru the defrost same way as you fixed

[@vicious-nv9be]

This is the best video I’ve seen on the vac system and how to properly diagnose it from under the hood to the cab ., what a money saver, experience pays , thank you so much for sharing this, well done sir 😊🙏👍💯

[@realfixesrealfast]

glad you liked it, thanks for commenting

[@rickmontgomery3037]

Totally agree!! 👍

[@jhofker]

11 years later and this video was still incredibly helpful. Thank you!

[@SHIRLENETAYLOR-zz6im]

12 years later and you described our car's A/C problem. THANK YOU!

[@Sandz_]

11 years later and this is still being used. Thanks for education! This is a great video!

[@daveprudaddy.3626]

You’re a Genius sir ! You’ve explained my situation perfectly. Now I know what my mechanic missed in his diagnosis. Wish you were my service guy. Thank you so much for your help and your knowledge.

[@tomcat452]

Lo 😆

[@danalarson8500]

Absolutely the best explanation I found in regard to vacuum leak and the hvac. Thank you for taking the time to do this.

[@realfixesrealfast]

Your welcome, and thanks for commenting

[@dreamrealitysyndrome]

Thank you, I've been working on cars for years but I never really understood vacuum lines. after fixing the HVAC door on an Expedition because of your video, I feel more confident about the subject

[@acetv4618]

Couldn’t have done without you. Took me directly to the root cause. Deteriorated hose at the check valve. Replaced the hose and back in business. Thank you!

[@joebudi5136]

Where did you find the replacement hose? I can't find any.

[@harryotaint9163]

This was more helpful than anything else the search turned up. I should have known the older dudes always know what they're doing!

[@realfixesrealfast]

Glad it helped. Thanks for commenting

[@AnOutgoingIntrovert]

What if you have no air flowing from the front vents at all? I don't notice any airflow on any fan setting, AC, heat, or defrost. Has it still defaulted to defrost? I have replaced the 3 AC fuses under the steering wheel, the blend door actuator relay, the blend door actuator, the blower motor, and the resistor. Still no air flow. 2001 excursion 7.3 2wd. Rear ac blows cold. No air flow at all to the front. I'm going to try this vacuum diagnosis and see what happens. Best video I've ever seen, great teacher.

[@angelolivera9]

Thanks for explaining the vacuum diagram, you certainly are a master in teaching, you saved me from doing unnecessary work. It turned out to be the hose to the vacuum reservoir. Thanks 100%

[@colinmoore68]

Thanks, you clearly know your stuff!!! Fortunately I watched the second half of your video which addressed my issue with a 2003 Expedition. Before anyone loses heart because they don't have a vacuum gauge or smoke machine, take a look at the check valve and the connections to the feed lines, all 3 of mine were perished and had holes. Fortunately I had some spare line, cut 3 pieces and it is back to good health. Major points from the wife as it is her car. I got lucky, but apparently that is the most likely area to go wrong. Good Luck.

[@sivucit]

I become addicted to your video, every day i look for any new vidoes from you. One can understand why knowledge and experience is important from your videos. you are a role model to any one about how to diagnose and find probems, you make most difficult problem in to very simple one. Awesome, Great, Great.. i dont have words to appreciate you. You rock.

[@scottgm321]

Great video! Opened the hood of my 97 F-150 and had an idea what to look for. The line from the reserve tank was broken and when I tried to disconnect lines from the check valve, it fell apart. All 3 ports just snapped off. Got a new check valve at the auto parts store and connected all the hoses and now I can step on the gas and the AC stays on the vents. Thank you so much.

[@davidoshea2260]

Thank you for this video, and your other 3 part video on the heater blend door. Fortunately, this job was much easier than the heater blend door was. For other readers, if you have hot/cold problems it is the heater blend door. If you have A/C vents vs. Floor vents vs. Defroster vent problems, then this video applies. The heater blend door is electrically controlled by a servo motor. The A/C vent vs. Floor vents vs. Defroster vents are controlled by a set of vacuum motor servos (driven by engine vacuum). Usually, as shown here, the problem on the vacuum controlled motors is most typically the vacuum feed lines or vacuum resevoir or the vacuum check valve. (Occasionally the problem is the vacuum servo motor, but that is less frequent.) In my case, I bought a $15 vacuum gauge (Harbor Freight Tools), and was fortunate to have a "really" easy to find leak, that I could in fact hear with my ear. Listen for a hissing sound. If your leak is much smaller, or much larger, then you may not get a hissing sound, and then you need a smoke machine. You can make a smoke machine, there are KZbin video's on how to make a make-shift smoke machine. One version of it uses a small (low power tire filler type air compressor). You can also buy one of those air compressors at Harbor Freight tools for cheap, but the other parts of the make-shift smoke machine you have to make, and it takes a while. I have one I made from a metal "jar" some Harbor Freight Tool air compressor line fittings, a bit of wire mesh I had sitting around, and some charcoal brickets and some cardboard (cardboard makes good smoke), brickets stay hot under low air compression.

[@patrickcharles3748]

David O'Shea ol o o m

[@joeramos4680]

David O'Shea I k

[@reesekitchens5325]

David O'Shea o

[@chrisreid8298]

I love it when videos explain how the system works instead of just showing what you replaced to fix it. My 2003 f150 was not switching off of defrost ever and I found that the hose on the intake side of the check valve had cracked. Replaced it and boom fixed. Thanks again!

[@realfixesrealfast]

your welcome, thanks for commenting

[@miltperez3375]

Have to say your videos are some of the best I've seen on KZbin. Your presentation is outstanding. You have saved me a ton of money . I have to say if not a teacher you missed your calling. Thanks again.

[@dannytorino851]

This is a great video. The way he explains it and diagnosed the issue. I tell you, the smallest vacuum leak like this, can cost a lot of money in extra gas consumption. I have OBD1 ford engine and the smallest leak makes the whole thing idle like hell and run like crap and run lean/rich/lean/rich. Im re doing all my vac lines and sealing the seams with JB weld on my air intake tube thats 30 years old.

[@jamesmcqueen2618]

Sir, you are the very best instructer I've seen on this king of problem. Thank you so much, I might can fix my problem now, you may have saved me a lot of money. What you said made a lot of Sense to me, God Bless You, (Mac)

[@billsisk2815]

Fixed my 1997 Chevy Express Conversion. It was a large Vacuum leak (use smoke). You are very good at what you do "SIR", especially at explaining.

[@realfixesrealfast]

Glad it helped, thanks for your comments

[@billwagner2693]

Best HVAC controller troubleshooting video I have found.

[@IRBent2]

Thanks for the detailed description and showing how the system works as a whole. Our 2003 Expedition initially started out as you explained where when going uphill it would quit blowing out the dash vents. Eventually it got to where it would only blow out the defrost no matter what position the control knob was in. I only had to watch the video up until you explained which line left the vacuum control valve and went through the firewall. I took a quick look at the line to see that it was cracked nearly through a few inches below the control. I cleaned both ends up the vacuum hose, slipped a short length of shrink tubing over one end, inserted the other end of the broken vacuum hose making sure to turn it so it would be in a position to reconnect to the control valve, then shrunk the tubing to seal the break. I'm not sure how long it will last but my guess is there's only a tiny amount of vacuum there to begin with. If it collapses I'll try again but make sure to double up the heat shrink. Last result would be to buy a coupling or completely replace the vacuum hose. But for now, it was a 3 minute free fix.

[@realfixesrealfast]

I'm glad it worked for you. But I really impressed that you took the time to think thru your problem and then locate the fault. Great work.

[@IRBent2]

@@realfixesrealfast My wife confirmed that it worked well for several hours yesterday while they were out. My only concern as slight as it is, I think I got the vac hose ends where it was broken to touch inside the heat shrink before I shrunk it down. If not and there's a gap between the ends, I suppose the heat shrink could collapse eventually due to the vacuum. Thanks for the help.

[@dougngn]

@@IRBent2 Congrats on finding the problem. If it fails again you know where to look ! ! Shrink tube has worked for five years so far on my truck.

[@jimmyfraser11]

This is one of the best videos I've ever seen on this subject!! Very informative! Thank you SO MUCH for sharing your knowledge and experience with us!!

[@realfixesrealfast]

Thanks, I appreciate you taking the time to comment

[@cwvoelker]

Very helpful to identify the cause and location of the right vac line. My 2003 Taurus had this issue and the vac line was broken, but hanging by a thread to the grommet that attaches to the dash. I was able to position the house back to the grommet, use some black silicone to seal and strengthen that seam and everything worked as expected. This video was the key for me.

[@realfixesrealfast]

Glad it helped. Thanks for commenting

[@StumpyVanLife]

Excellent video! I had the same exact problem on a Ford Van about a year ago. It turned out to be the same exact vacuum hose! Maybe a pattern failure? Thanks for posting this and all your videos. Good job, carry on!

[@sam111880]

I did learn apparently when there is no vacuum on these models the blend door defaults to defroster setting (so it seems that the default for vacuum based blend doors is 0 vacuum for defrost vent routing) ...All the other blend door positions for front , by feet ,...etc are a certain percentage of vacuum

[@dsadave]

You are SO helpful!! A cut vacuum tube is my problem. You are a very good teacher. Thanks for sharing your knowledge!

[@strokewarrior5762]

Glad it helped, thanks for letting me know

[@Sileff]

Finally someone who knows what they are talking about. Thank you sir!

[@craigcarrillo]

I really want to thank you for your time to not only inform but to also teach by real life examples for those at home. Like the old saying about teaching someone to fish and they can catch fish for a lifetime.

[@strokewarrior5762]

Thank you, I appreciate it.

[@jon-kl9mk]

So there's only one vacuum line going into/ coming out of the vacuum reservoir?

[@drm315]

Thanks for taking the time to make these videos. I find the information given here to be THE BEST on all of youtube, and I watch a lot of car repair videos. In addition to your vast knowledge I am impressed with your presentation, very clear and easy to follow. I've been working on cars professionally for more than 25 years and learn something new with each video. Keep up the good work, looking forward to the next video!

[@skylarkendrick656]

instaBlaster...

[@kevingreen342]

Great video the actually takes the time to explain how the vacuum control system. I have been troubleshooting issues for days with my van, trying to figure out why I cannot direct the heat where I need it. It is single-digit weather and I cannot get my defroster to work.

[@Zelaznogsiul-63]

The same exact line broke completely off on my 2002 f 150, I found that out yesterday while I was putting the engine together hopefully for the first and last time. Great video.

[@joeysowell116]

Very good teacher! That’s the way they all should be explained on KZbin. It would make it so much easier. Thanks. Now I know what to do.

[@realfixesrealfast]

Thanks Joey, good lluck

[@joeysowell116]

I found it, it fixed. Thanks for your help. I subscribed to your channel.

[@michaelbladebrownwallace3552]

First video was.my issue.. replaced reservoir, vacuum hose and replaced some tubing and I was back in business... thanks for this video..

[@1976DannyG]

Simply amazing explanation. You took a lot of the mystery out of vacuum lines and check valves. Smoke machine really cool. Excellent troubleshooting and repair. Just subbed.

[@radajamesjavelosa]

Thank you sir, when i heard you mention accelerate up and the air from front vent transfer to windshield defrost, it's same problem i got on my 03 Expedition vacuumleak tubing same spot behind the battery, the AC is Fixed because you're video, is very helpful , thank you again sir!!

[@realfixesrealfast]

Glad it helped, thanks for your comments.

[@jockodog2009]

Great diagnostic instruction for both intake source line and component lines downstream. Thank you.

[@robertodebeers2551]

Outstanding video. Very helpful, especially the vacuum-check valve and checking for broken vac lines.

[@harryreilly1760]

Thanks for helping with my A/C that was not blowing through the a/c vents. The information you gave me was great and you how the system worked and not just replace everything in the A/C unit.

[@strokewarrior5762]

glad it helped, thanks for commenting

[@strokewarrior5762]

glad it helped. Thanks for commenting

[@jesusmejia1334]

This was a good video. I think on some older fords this same exact line is hooked up with the EGR. Mine line is completely ripped off. Gonna fix it this week.

[@mikelangelo187]

I've been wondering where that fishing line goes and why I can't get cold air out of the vents. Now to check behind that battery. Two birds, one stone. Thank you, sir!

[@snocrushr]

@Mutleytech Yes vacuum is measured in inches of Mercury, the chemical symbol is Hg

[@miken4022]

2001 Ford F-150 4.6L would go to the defrost vents upon acceleration and back to vents when letting off the pedal. This was by far the best video I watched but upon inspection the plastic hose coming from the vacuum reservoir had a crack. The crack was only 4-5 inches from the check valve and easy to work on. I placed black tape over it for now until I can get some replacement hose. Took it for a test drive and it is working well until the long term fix can be put into place with new hose. I would still like to get a vacuum gauge and smoke machine because who doesn't like new tools. I want to say "still useful after 13 years" like everyone else but...that would be pointing out the obvious.

[@realfixesrealfast]

glad it helped, thanks for commenting

[@travishogsett161]

The only video that followed the line I need to know thanks

[@johnstanke8679]

You nailed it! That is exactly what I needed to hear. The mechanic could not find the problem. Thanks

[@jeremydiy]

Best and cleanest fix I’ve seen yet. Thanks for the video, I’m going to do this exactly.

[@artboytidwell]

Well done... Great teaching style and very clear instructions. Thanks

[@pwcoon]

This man is SOMETHING ELSE!!! Can he come live with us!!! I hope this generation has half the sense he has!!

[@realfixesrealfast]

Thanks for your comments, I appreciate them

[@jhonnychingass6252]

Very good info,,,I never thought ac on cars was vacuum controled,,, I thought it was electronically...thank u so much!!!

[@ThePond2023]

Thank you so much I just spent 3 hrs under the dash getting to my ac door actuator only to find out mine works just fine, the 2nd part of this awesome video was my exact issue! You are a fkn legend! God bless you.

[@adrianflores1916]

I really appreciate you for uploading you’re videos I hope you well. Very simple and easy fixing with you’re explanation god bless you sir

[@richardallanjoseph]

@realfixesrealfast - Sir why does the manufacturer connect the a/c vent doors to the vacuum? Why does the vacuum something to do with the air door control system? I thought everything is manually controlled at the knob on the dashboard?, Thank you Sir.

[@brianedwardcasey]

Thanks for demonstrating the diagnostic approach and smoke test !

[@AnthonySvt_]

This video saved me a lot of time and money I guess the previous owner was doing something with this and put the valve backwards

[@spelunkerd]

Brilliant video. You regularly find the huge gaps in my knowledge foundation. Say, is there a "poor man's smoke machine" that anybody would suggest?

[@rickchapman3707]

Really enjoyed watching your video I dont know any mechanics in europe to have a smoke machine , ive heard of them. Now i want one hope they are not too expensive. Great Video Top mechanic !!!

[@lyleswavel320]

This man finds the problem and fixes it, amazing

[@jalapenovibes]

Awesome video. I have a Ford Windstar that keeps defaulting to the defrost vents. Now I know what to look for! Thanks, you guys rock.

[@eds6569]

Old timers would just blow smoke into the line with a cigar/cigarette but your fancy smoke machine is cancer free and prevents vehicle owner complaints of cig smell. 😆

[@chriss4365]

how do you re vacuum the canister? I replace that small hose that goes in the fire wall and now it will switch from defrost to floor but not to vents if it goes to the floor it must have vacuum right? Where does that line connect on the control panel?

[@antoineford9422]

Hi had smoke test done couldn't find the leak paid $50.00 buck for nothing, I have a 1993 Pontiac Bonneville se plus I was trying to tell my repair it control panel doesn't make the little blow noise when you are changing the mode you have vacuum leak right?

[@wyattandwill12]

I was having issues with my 98 Cherokee and it turned out that the vacuum line was gone from where the hose gets smaller after the T down to a few inches before the firewall. I have some hoses and I wanna see if it’ll help fix the lack of power too since it’s complete open with a 1/8” hole.

[@sam111880]

nice explanation on how to uses a smoke tester machine in vehicles that have blend doors operated by vacuum. But for those that are electrically actuated completely using no vacuum or even worse the old cable driven ones then hope they are easily gotten to or the mechanic will have a ridiculously hard time to switch out the blend door / splice into a cable ...etc depends on car

[@lawrencerasmus]

Finally someone who knows something and how to explain it.!!!!! Thank you

[@j.j.gonzalez8945]

You sir are a teacher, Thank You

[@dougharn7605]

Great video! I was replacing the worn out rubber boots on my check valve today and the hvac hose came out of the firewall....it is only about 9 or 10 inches long from the T at the check valve to the other end that goes into the firewall....my question is what does this other end connect to and how do I get to what it connects to.

[@CynthiaJ7777]

Great info! Would it still be the same issue on a 2015 Nissan Murano? When I first start my SUV, even if the vents are on head, they do not blow any air. The system will SOUND like it is blowing, and as you turn up the flow, it sounds louder, so it is working. However, air doesn't come out. The only way I can get the air to start coming out of the head vents is to turn the vent to front defrost, listen for a little clicking sound indicating the air is then blowing into the windshield, then I can turn it back to head vent, and it blows from those vent. Is that an actuator issue?

[@erikdavis1646]

An excellent no-nonsense walk through. Thank you.

[@lesterthurman8104]

Erik Davis

[@zazarays]

yup

[@moofushu]

Does this same test work on the gas emissions with the evaporator control valve system on cars gas tanks?

[@thedobermangang3503]

This is the best mechanic on KZbin I don't care what nobody say,. This man k nows his shit..

[@BoatLakeHouseKids]

THE BEST LESSON ON HOW TO TEST VACUUM LINES EVER!!!!! thanks' FOR THE EDUCATION!!

[@realfixesrealfast]

Thanks, glad it helped

[@3Krazy83]

I have a different issue: I have air coming out of the defrost, middle, and floor vents at the same time. When I raise the temperature, the passenger side gets hot but the driver side remains cold. Any suggestions? I have a 99 Buick Regal.

[@petepatterson5651]

Awesome I believe I can fix my truck now...wish I had a smoke machine, Where can you get the repair vacuum hose

[@tomd720]

Yes, the absolute best video on this subject . Hope it helps with my problem. Thanks !!!

[@pokeys87jag90]

Big thanks to you! Fixed my a/c and solved my problem in 3 minutes.

[@rubio7922]

Where does the heater valve vacuum hose connect to?

[@nasedo3129]

That smoke machine is pretty cool, I wonder where to get one and what they cost.

[@bohemialite6371]

That was a great video on that but I have a 79 Lincoln Mark V that does the same as soon as I accelerate the blend door closes to the air conditioner and it comes out warm and as soon as I let go of the gas I get the cold air come back do you have any idea more or less where that might be located on the Lincoln Mark V 1979 I hear that was a common problem on the Lincoln's but I just can't seem to find it

[@naranjoceidy]

What kind of hose did you replaced it with and where can I buy some?

[@Grannyhauenstein]

My problem is that it will go to floor and vent but not defrost. When I turn the mode dial, and place my hand on top of the vacuum motor, you can feel the plunger moving up or down when you turn it to floor and vent, but when you turn to defrost, the plunger doesn't move. I tried a new vacuum motor, but it did the same thing. I tried a new HVAC control panel, but that didn't help either. Vehicle is 2001 F150. Any suggestions would be appreciated. Thanks!

[@CoolasIce2]

@logyscott He is revving the engine and then closing the throttle. You are seeing the vacuum rise as the throttle is closing.

[@ronhebert2304]

I have a 2006 Explorer and behind the knobs that turn the a/c on is a black flat piece of plastic that broke. My a/c blows cold air out of the top defrost vents but not the a/c ducts. I took it into the Ford Dealer and they charged my $961.00 to fix it. Said my blend door was broken. I took my glove box out and looked up and saw where the flat black piece of plastic had broken. Ford said I needed the Blend door replaced? Was there a way to fix this without replacing the blend door? Blend door was $361.00 and labor was $600. That hurt, wish I could have fixed it. Any info in this black strip of plastic for future fix.

[@jjplane1493]

by chance what is that plastic line that goes into the firewall to the dash? what is it called?

[@ddog210]

Thank you for this video. It saved me a lot of trouble and headaches.

[@grawey77]

Simple repair with the right equipment.. The smoke machine is necessary.

[@jamesmcqueen2618]

Very helpful, your a good mechanic. I'll try to remember what you taught me,

[@devinnewell2615]

I

[@ahill007ny]

THANKS!!!!!! HAD THIS PROBLEM ON A 2000 CHEVY IMPALA 3800....LINE WAS MELTED REALLY BAD....WHICH CAUSED A/C CONTROLS TO DEFAULT TO DEFROST MODE, WITH BARELY NO AIR COMING FROM THE VENTS :)

[@haterbilt9428]

Just curious shouldn't you have pinched off the engine vacuum and the line running to the reservoir to narrow it down to the line it ended up being? Your gauge shouldn't have dropped because you still had engine vacuum when you blocked the reservoir. Regardless very helpful video thanks for taking the time to make it.

[@joecostu1571]

Which steam machine are used thankyou

[@alcameron6071]

That’s the exact problem I’m having with my 2001 Dodge ram 1500 pick up truck. If I am cruising around at normal speed the AC is blowing through the vents. As soon as I start going uphill and I have to give it gas it stops blowing through the vents and comes through the defroster. As soon as I let off The gas pedal, I can hear the door slam closed and the AC once again blows through the vents. I guess I need to start checking under the hood for those little leak. Thanks for the video.

[@realfixesrealfast]

Glad it helped, thanks for your comments.

[@2012isRonPaul]

what smoke machine is that and what range does the gauge has to have? 30hg?

[@traviscatherall3683]

Thank you . Your a god of vacuum system. What is that smell in the vacuum from.

[@jeffreyeiford2750]

Hey Wayne (I think that’s ur name ). What is a good vacuum gage ??

[@joeyw4442]

So.........if I have this right, vaccum leak has nothing to do with the main blend door. The one with the electronic actuator and adjust heat/cooling. the vaccum leak would only cause vent circulation issues? i.e air coming out only on defrost port, or only floor port, or only panel port?Nothing to do with the air circulation temperature?

[@jrboi1960]

This is the same problem I am having with my dodge, thank you for the video.

[@CoolasIce2]

@richardallanjoseph I'll answer that. Some economy sub compacts might use just cables to activate the doors, but that takes a little more effort. With more elaborate HVAC systems with a lot of options, it's easier to control the doors and valves using vacuum.

[@josephfiumara9065]

What a great video ! This has helped me fix my dakota

[@duranjazzo]

Just what I needed to know for my 01 Taurus. Thanks