Defrost Only? Cheap and Easy Fix

This is a very common problem on vehicles with vacuum actuated HVAC controls. The plastic vacuum lines break and the system defaults to defrost.

[@jameslookstwice]

Anyone who post's videos like these to help others, deserves a like.I really appreciate you.Thank you for sharing your knowledge to help others. ❤

[@cgrooms599]

6 years later and you're still making a difference with people. Thank you!!

[@skullpimp4684]

And most mechanics will tell you that the actuator needs replacing. Just what the mechanic we use for our company vehicles told my boss. Wanted to charge more. Because replacing a little line. Wouldnt be able to charge the $289 he wanted to replace actuator. Thank you for telling the truth. I was able to replace it myself. Saving the company money.

[@nudetaynehatwobble]

Your employer likely doesn’t deserve you. Hopefully he/she values your additional efforts to help their company!

[@chenisikymoh]

i can't find the tube any where inside my 2012 GMC van ( under the hood ) , it may be easier to find from the bottom ?

[@Z71_Kevin]

Yea S10's are notorious for this as well, I had a 03' S10 with a 2.2L and I was lucky the vacuum leak was under the hood near the brake booster. Great informative video!

[@frankenstein70]

Thank you and thanks goes out to KZbin as well, for making this video. You saved me an unknown huge amount of dollars. My air conditioner on my 1996 Olds was working only through the defrost system. I watched this video, and lifted up the hood. I found a plastic vacuum line unattached to a purge valve. I reconnected it and the air conditioner works like new again. Thanks.

[@drazi3356]

Uhhh youtube didnt make this video.

[@TheTradeuser]

Many thanks for the information. My GMC van is doing this and could not find information anywhere. Thank you sir for posting.

[@monkeygrrl2]

thought i needed a blend door actuator , had this same issue in my 97 s10. went out and fixed it for 2$ ! thank you

[@paulparoma]

You are a real expert mechanic! I had the same problem on my 1978 Buick Electra many years ago. No one could tell me exactly what was wrong. Too bad there was no Internet then, and you were probably a kid not even old enough to drive.:)

[@richardcoughlin4478]

Absolutely! Thank you. I had ripped open the panel to investigate and was ready to test the opener solenoid. Thanks and thanks and thanks!

[@alief88og]

Excellent video. These videos are a true gem and learning experience.

[@marthaaguirre8661]

Thanks so much. Appreciate the info. Big help just in time for summer. Thanks again

[@artisticprecision4383]

My 97 Dodge 12V Cummins just did this yesterday. I thought it was the recirculate door but after dropping the blower motor it was clear that wasn't the issue. Hours of youtube searching later and I'm almost positive this is it. Blows good but only out of the defrost vents. I'm glad I found this before I fabricated return scoops for the dash vents!

[@chevrolet355]

Do you want to sell it?

[@hectorolivos7373]

Thanks very helpful I fix my 1996 conversion van it was that vacuum line broken now works good.

[@pierrehere762]

Great video, I like the way you explain the system. Easy to understand but not too much blah blah. Easy way to eliminate other causes- I turned my vent to floor only (floor wasn’t getting any heat (or any air blowing) and instead of coming out of the floor it came out of the defrost, which like you said is a fail safe so now i know it’s a vacuum leak not a different cause. Thanks!

[@charleyswanson1473]

Our church has a 2001 Chevy Express 3500 passenger van that cools great on the rear air, but only marginally on the front air. The air comes out the correct locations based on the switch settings, but when you turn the front control from Max to A/C, it gets warm like a blend door is not closing or something like that. Another question I have is when the rear air is on, the compressor runs normally, and the suction pressure is around 35 psi, but with it off and only the front a/c on, the compressor short cycles, the suction pressure varies between 22 psi where it cuts off the compressor to about 30 psi where it kicks back on and then repeats the on / off cycle, and the return line to the compressor which should be cold to the touch is warm full time. Any suggestions???

[@Cetega]

Useful information, this sounds exactly like the problem I'm having with my 2000 Monte Carlo SS. Now to figure out where the vacuum line is on my car, heh.

[@benjamintucker1964]

thanks Daniel, that's all I needed was my faithful youtube look up, and sure enough there was an answer to my problem

[@coololds85]

I have the same problem on our 89 Buick and the shop is telling me the vacuum lines look good but I checked the check valve and it was bad... plus my vacuum purge canister solenoid is also making rattling noises at engine idle. Could the solenoid cause that issue too if none of the vacuum lines are broken? I already spent a lot of money on other repairs and I wouldn’t want to spend an arm and a leg if they have to remove the dash which I don’t want...

[@crazyjdkid]

Daniel what would cause my electric radiator fans to stay stuck on high speed. My temperature sensor is working correctly and my defrost/AC is off. As soon as the engine is started it brings the fan from low to medium to high within like 8 seconds and stays on high no matter what. My OBD2 reader is reading the correct coolant temperature and it says the radiator fan is on high. So the vehicle knows the fan is on the highest setting. The relays work correctly as well.

[@lewbear6738]

temp sensor for the fan is different to the temp sensor for the gauge, its probably the fans sensor that failed.

[@noahmoore8313]

I have a 1996 gmc seria 4.3 liter engine my heater and ac are stuck on the floor setting I haven’t check the hose that you described in this video yet but I’d like your feed back to know if it could be something else

[@rahalati]

Very useful information, thanks. Do you think Toyota land Cruiser 1998 uses the same approach? I am having kind of similar problem accept that it comes and goes

[@metallickeyboard]

Finally, someone who’s helpful, thanks for the info man!

[@DayTripperLennon]

This was extremely helpful, thank you so much!!

[@Bruce_Bruce632]

I have a pro star cold air comes out of defrost same the as you shown in video.i know car and truck different set you but I need to figure out how get my air come through the vents

[@kiokiperezkiokiperez746]

I think this the issue that i"m been looking for,, thank you

[@djbis]

Excellent. Diagnosed my issue with this video. Thank you so much!

[@bigjoe2458]

I have a 2010 Chevy Express conversion van. The AC works fine for awhile but the AC will soon turn to hot air and continue to stay hot until I turn the AC off for a few min. then I turn it back on then it's cool again. this seems to happen under extreme loads on hot days when the fan runs at top speed. Any clue as to how to fix it?

[@sweetiepienumber1]

Does anyone know if a 2004 would still use the same vacuum hose system? They didn't switch to a vent motor that year dud they? I don't think so, but I don't have access to the van right now. Thanks for the video!

[@migruiz142]

hello would this also be true on my 2002 chevy suburban? is has the same problem.

[@trav885]

I have the same problem on my 02 Buick LeSabre. The air is cold but it only blows from the bottom. It barely comes out the dash vents. Can you help me out Dan?

[@lnandousa18]

You are the best! That's what I was looking for! Problem solved! Thank you!

[@jeffmarshall7409]

I have a 1998 Buick LeSabre and the blend doors that are vacuum operated goes to defrost only a on a/c. There are three vacuum diaphrams under the dash and I have took my snap-on vacuum pump to them all and all I get is one that will make it go to the vents barely. My Chilton and Haynes book wont tell me anything. I need some help please. I can't find a you tube video even close to help me. The a/c would come out the vent sometimes going around corners and then go back off to defrost and sometimes when you touched the brakes it would go on to the vents, which is weird because you would think it would draw the vacuum out of the a/c controller.

[@louiscampbell1416]

I'm just glad there's intelligence out there thank you for making this video God bless

[@rigomelendez2146]

Thank you so much for this great information you save me a lots of money

[@nitroxur]

Do you have a vid for the same thing for a ford Crown Victoria? I have the same extact problem too being stuck on defroter too!

[@Solitaire401]

This just happened to me this morning. I went out early to beat the heat but on the way home from the grocer I could really feel it not working. It was coming through the defrost and steaming up the windshield and it was coming out the back blower but not the ones in front of me. I have a 2002 Astro. Your dash looks just like mine except I have a separate air controller for the back.

[@juliebaldwin8730]

Solitaire401 me too same make and model

[@jacobsantana603]

I have an 09 CVPI that did this on the way home from a road trip. Luckily, it wasn't too hot or cold outside. I figured it was the vacuum hose because the air still blows strong. I just have to find the hose that's busted, I guess lol. Thanks for the video!

[@nudetaynehatwobble]

Did you ever find it?

[@jacobsantana603]

@@nudetaynehatwobble I did! It was the black line coming from the controller, through the firewall, and onto the vacuum pump. It had cracked from age at the connector to the pump. I snipped away a little bit from the line, reattached it to the pump, and immediately had all my AC settings working again. Very easy fix

[@nudetaynehatwobble]

@@jacobsantana603 thanks for the update! I’m pretty sure that’s what I’m dealing with too. Gonna try this before throwing parts at the problem!

[@jacobsantana603]

@@nudetaynehatwobble Good luck and hopefully it was as simple as mine was! Let me know how it goes!

[@chrisj2199]

thanks this video helped solve my problems with my heater

[@CanadianTalent1]

Same thing happened on my 92' Dynasty. Except it used rubber hoses. Took 22 years for them to fail!

[@Seekay92]

I dont have a pipe from my vaccume reservoir . My ac blows weak and condensor doesnt cool much. There is no leak either. What should i do now.

[@67RcodeFairlane]

My 91 Taurus SHO did the same thing. but instead of replacing the hose I got some heat shrink and put it over the break and put zip ties on both ends of the heat shrink. actually worked pretty well.

[@nudetaynehatwobble]

That’s not a bad idea either

[@McCurtainCounty888]

How did u get the heat shrink on without cutting hose?

[@peterford9369]

I just got done doing plugs and coils on my 2000 E150. Now my blower is on defrost only. Verrry, possibly I either didn't plug something back in or broke a small vac line. Thanks for the fact about the air in defrost position as a default. I thought maybe I forgot to plug a plug together. Back in I go. Thanks.

[@letsthinkitover1]

ok I have no defrost and only have lower blowerl so what can it be ? I pute new blower motor and vacumes out dirt cleaned the coils and put in new switch and new resister still will not blow high speed a mech spent one hour so far could not find whats wrong. wants mw to bring ir back in the morning again

[@jannahlovsky1677]

Hi mister, I have got GMC Safari 1995 but it is an older interior with a vertical AC controller. There is a problem .... the air only flows through the front vents. Even when I switch to the windshield, HTR or AC, hot air still flows through the front vents. Any recommendations?

[@CorruptedKarma]

Question, when you say only come out of the vents, do you mean no air comes out of the vents? I have warm air coming from the vents and cold air coming from defrost

[@abbieabbie6818]

Same problem but I also had heater control valve replace n vacuum line on it , where that line go 2000 Astro van ?

[@adamweatherford2795]

Just had this happen. Looked under the hood. Broken line. Fixing it tomorrow. You just saved me a ton of money!!!!! Thank you!!!!!

[@jameswhite2084]

Found the solution I've been looking for 2 years

[@bristoldaffern8898]

Hahaha Only had this issue for 2 months and what's a saw this it's obvious

[@Nate......]

This is the exact problem I have been having with my 97 Z71 I hope this fixes the problem Where can I purchase that hose ?

[@raynic1173]

If this happens on the road and tubing replacement parts are not readily on hand, stop at a gas station and grab some cardboard out of their trash. Cut a strip 6"-9" wide and 4'-5' long and crame it down along the windshield as an insulator/ deflector. This will reduce coolant loses to the windshield. If you can't get the cardboard to stay in place by friction, just wad up a couple of whatever and wedge them in there to keep CB elevated. Of course don't block your view of the road or front end of vehicle.

[@chenisikymoh]

so smart !

[@rughubb]

So what happens if you don’t hear the hiss?

[@captainhateahoe9800]

Would that mean I need an actuator? My a/c is doing that on my 08 dodge nitro and I replaced the control panel but that didn’t fix it

[@MrMundaa]

\[HAVE A 94 CADILLAC FLEETWOOD STUCK IN DEFROST ANY HELP THANKS ARTHUR

[@lorenzomontgomery5058]

It's a lot of things going with my car ... And this is 1 of them thanks

[@cruzreyna795]

Would it work on a 2003 suburban?

[@blaze2051]

what size did you use in the video?

[@Foxbat_a]

I probably have the same problem on my 2007 Subaru Legacy, but it has electronic AC controls, can it still be the issue?

[@slappytaffy895]

Where can I get that hose for replacement?

[@PrimalurgesMiami]

Dan I have a similar problem on a 96 Corvette. The only difference is that the air started blowing out of the defroster for about 5 to 10 seconds and then comes about 90% out the front and 10% out of defrost. Could this be a check valve or vacuum hose or both?

[@taliakuznetsova7092]

possibly could be a leak that is partial and causes enough of a leak that it goes partial setting.

[@Drives31forhalo]

this is why I like either cable controlled (like my 02 ford focus) or electric, provided it's not using crap actuators.

[@debonairecatalina6570]

Drives11 shit, my 65 Catalina has linkage controlling the routing of air for the heater

[@nudetaynehatwobble]

What was the inside diameter of that rubber hose?

[@Boyleheights13]

Thank you Daniel..🇺🇸🇺🇸👍👍👍👍👍

[@officialsaint97]

I have a 1997 chevy 1500. It doesn't blow any air through the vents so I leave the selector on the window defrost its fine, but when I switch it something I hear this funny groan from what looks like the blower motor the sits under the glove box on the passenger side. I was told its either the motor or the actuator. There isn't an AC hose so I don't use it, but I want to figure this problem before getting the AC hose, or if not having the hose is the problem

[@mikecargal9960]

Is I️t the same problem with heat stuck on defrost? 97 gmc jimmy

[@tomd720]

I replaced all the vacuum lines and the check valve on my 2000 astro van . It did not fix the problem. Air still won't come out of front vents. Any suggestions ?

[@jackparkin9849]

Great, I just need to find that vacuum hose on my 93 Bounder- Chevy 454 EFI. Thanks

[@Littlervrentals]

What Size Is That Vacuum Line??

[@dee2250]

And there it is..That is Exactly what happened to me.. Tomorrow I am heading to O'Reilly's for that hose

[@hillaryclinton2415]

Same problem with dodges.. ended up bypassing from engine to black line on controller assembly..

[@marissaw1586]

Wonderful! We've replaced the AC Control Unit twice without success. Going to check this out in my 2000 Dodge Ram Van. Thank you!

[@jamesmiddleton5304]

Having the same issue on my 2000 Ram van. Guess I need to figure out where the the line goes.

[@jacobware8661]

@@jamesmiddleton5304 did you find where it went. It would be great if you could let me know bc I'm about to try to fix it on a 1998 Ram van

[@jamesmiddleton5304]

@@jacobware8661 no I didn't. Sorry. Still on my to do list as with several other things on the van. Good Luck.

[@jamesmiddleton5304]

@@jacobware8661 I finally found parts of it. Fixed a major crack, but still isn't working correctly.

[@jacobware8661]

@@jamesmiddleton5304 I was actually able to fix it a few days ago so I'll just give a bit of info specific to the van. From under the engine cover you can look where the control knob is on the other side and see 4 or so vacuum tubes. I just followed each of them back to the other side under the hood and kept following them until I found the broken one. I hope this helps

[@bigfrank1070]

thank you this fixed my problem

[@paulhumphrey3767]

I got a 2000 Chevy Silverado. when u push the gas it smoter an dies.

[@fishburnfamily]

Thank you so much!

[@simplecarnivore]

Mine works sometimes on my Honda Odyssey??

[@Tumusica311]

My 03 ford windstar upon acceleration it changes to the defrost...will this be the same vacuum hose?

[@Bmxicano2]

I have the same problem. Did you find the solution?

[@Tumusica311]

@@Bmxicano2 no I havent🙁

[@urbanpat1714]

I think this is my issue on my 1989 Oldsmobile delta 88 royale! now to find that damn hose...

[@etp_23]

Does this apply to 03 suburbans?

[@lorenrobertson6017]

Thanks very helpful

[@Erix7810]

Vinyl vacuum hoses that control heater controls. Thank you GM.

[@ryanharmon1719]

What size of rubber hose did you use, and where can you buy it?

[@helivesonforever]

What if my AC in my Dodge truck goes to defrost when I accelerate moderately hard?

[@Mdudeman13]

Sounds like the check valve that Daniel was talking about might be leaking, therefore it doesn't hold a vacuum in the reservoir unless the engine is constantly supplying it. (light or no throttle)

[@helivesonforever]

MetalGear Mine is kind of the opposite though. It works fine when at idle or accelerating lightly, but stops after it hits about 3000 rpm. Could it possibly be a split line? I've also heard of some people saying that the intake gaskets might be leaking a little bit.

[@EmonneMarkland]

Where do you get the hose?

[@porfiriodiaz4552]

Auto parts store.

[@mannya5343]

I think this is what happened to my 06 Chevy Colorado. I took it to a local mechanic, he said he charges 120 bucks just for a "diagnostic" not including labor and parts... Now I don't know too much about cars, but I'm pretty sure I can change a damn hose.

[@zakaria23045]

My crown Vic 2003 has the same problem. but I could not locate the vacuum line. please help.

[@caveman123ization]

Your Crown Vic does not use vacuum lines like the vehicle in this video. It uses a electric motors to move the doors. Information on troubleshooting HVAC systems in Crown Vics is very plentiful. Do some research and you will figure out how to fix your problem. My favorite source of Crown Vic information is www.crownvic.net. This forum has write ups and guides for pretty much every issue you might have with your panther platform vehicle.

[@zakaria23045]

caveman123ization thank you

[@davethebarbarian2363]

Quick question for you then was it only a few models that had vacuum operated ones? I pulled the whole box from under the dash in a 2004 mustang and it was vacuum operated I wanted an electric one but being it'll be going under the dash in my 78 trans am its small enough and it works with very little modification to the fire wall.

[@TheLegend-pi4yj]

Alright so i dont have this problem... but i was wondering if it is normal for the temp gauge to go about halfway when the defrost is on the entire time the car is running (being driven for several hours throughout the day being turned off and on) 95 corolla

[@JoseRodriguez-tx1qz]

Hey guys I have a problem with my 2008 Honda Civic & I wish someone could please help me out. My car only blows air through the front vents, not through the windshield or to the feet. What can possibly cause this? It sucks because on cold days, the windshield fogs up really badly when I turn on the heater since I can't change it to where hot air blows on the windshield.

[@hitrun9227]

Good chance your actuators are not funtiining right I'd start there

[@kingmike40]

When I was a kid my parents Buick, think 1970 electria with 455, would do the same thing. My dad's fix wasn't so much a fix because he didn't know how the system worked so he would bypass some hoses and plug them. When the seasons changed we would have to remember which hoses to unplug and plug to get the heater/defroster for winter and the a/c to work in the summer. I laugh now, but it was a pain in the a**.

[@southernglittershine2712]

kingmike40 he bypassed the heater corr

[@alexandercardona4900]

Thank you very much

[@tarassu]

BMW uses rubber hoses with fabric protection. They last 14-16 years. But still fail. 3-5€ for few meters. Luckily AC system works with servos that never fail.

[@kaleighhodges885]

My vents are stuck on the front vents

[@liltrayhomie2k]

Mines only stuck on the vents in my Impala SS 1995

[@kennethjohnson258]

I just bought a Chevrolet van 2500 2011 but the air only come out threw the defrost and the floor. What do I need to do. Is it the blended motor?

[@Jemaro671]

I have a question. There are two ac vacuum openings coming out from the fire wall. Can you please help me routing of the vacuum lines. Hope to hear from you soon.

[@mitchellmccall377]

Dear God thanks brother

[@paulsthormes251]

Thank you

[@breanacummins2705]

have this going on in my 2010 dodge nitro... and its 100 degrees out 😒 perfect timing

[@tino8080]

hi my 99 tahoe ac works on rear but not the front side what can be the problem? plz help has enough freon,front blows warm air when the rear blows really cold.

[@southernglittershine2712]

tino8080 my 2002 yukon is doing the same thing. Ice cold in back cool/warm in the front now it’s blowing through vents and defrost in front We changed the fan clutch, climate control panel, and passenger actuator none of them worked. I know there is 3 actuators in my yukon passenger side under driver side and behind the center console behind the radio etc. Mine is also topped with Freon and my compressor works it’s very frustrating especially living in Florida where the heat is brutal

[@jasminearredondo8012]

How much would something like this cost at the shop? I honestly don’t think I can do this myself😂

[@andreagreen1467]

Usually around 100

[@nanpoe]

Same problem with my 2006 mustang but I can’t find it

[@rbeck3200tb40]

I have the same problem on my car its a 97 mustang

[@HijodeDios305]

Any luck on finding the lines Bro?

[@raidernationcali]

How do you do the actual fix though? im no mechanic