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Thread: does anyone else's vents blow only hot air?

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    back from the land of JK 2k2wranglerX's Avatar
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    Default does anyone else's vents blow only hot air?

    ok, this sucks so bad. i know i don't have AC, but when it's 60 degrees outside, i'd expect the cold setting to be somewhat close to that. not the billion degrees . . . .ok so maybe not that hot, buti only get really really warm air at the coldest setting even when it's chilly outside. . . . is this normal?
    03 TJ sport
    4" full traction long arm
    full skids
    solid industries 60
    4.88's, arb's, alloys
    kilby oba
    mastercraft seats.. etc etc etc

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    I think the engine heat probably overrides the outside air temp.


    Eric
    '98 TJ Sahara

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    Here in the desert I get 110F air blowing through the vents. I wonder why?
    89 YJ, modified 6 banger
    95 YJ, stock 4 banger

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    mine blows warm air at the feet all the time.
    my 97 Sahara did the same thing.
    99TJ sport, 5.5" RE long arm,44's, flipped d300 w/4:1, 37" MT/Rs----SOLD
    99 WJ stock
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    My Jeep just started doing the hot air only thing and I have no idea what triggered this. The air used to blow cold (no a/c either) when it was cool outside and now it only blows at the hottest. Even when it is turned off, the side defroster vents and floor vents blow hot air. I ended up covering the vents with electrical tape and it werks. I would like to know hot to fix me heat problem though in the rest of my vents...
    97' TJ SE

    4.88's, D30/ D44 locked, 4" Pro Comp Stage I, 2" body, 35x12.50 Pro Comp X-Terrains, Avalanche Rockers, Rock-It Intake, Exhaust...

    Yes...Its a four banger on 35's!

  6. #6

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    Mine does it. I hate it. I also have AC but something broke that directs the air to the different vents so now mine won't blow out the upper dash vents. only the floor and the defroster. Oh yeh, that is when I use the defroster as the AC.
    Black, 97 Jeep Wrangler Sahara with too many options to list.

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    OffRoadJeep1; check for loose vac hose under hood...

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    Default mine does it too

    i have no AC either and mine used to blow cold, or at least it wasn't hot. then one day it rained really heavy and i ran the defroster all day on hot. and since then i can't get any colder. any one know how to fix it?
    '98 TJ Sahara... i've done some things to it. lots of things. too many to list in a sig.
    The highlights being the one ton axles, the SOA and the tube work. discussion over.

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    I had the same problem, but there was nothing wrong with my Jeep. In my case even on "cold" the air was noticably 5-8 degrees warmer than outside air temp.

    I took apart the airbox to see how it worked. (And installed A/C at the same time) Basically there is a diverter door (it is cable operated in 97-98 TJs and electronic in 99+ TJs) and it swings back and forth to direct air over the heater core.

    Unfortunately, even when it is turned all the way away from the heater core, the heater core will still "warm up" the entire airbox, plus there is still a large slit where hot air will mix... To try to explain, the diverter door blocks off air from going INTO the heater core, but there is nothing that stops the heater core air from coming out into the main flow of air. (they just assume that if air isn't blowing into that side of the box, air won't blow out)

    If you live in a warm climate, the easy solution is to buy two short pieces of heater hose, and block off the heater core entirely. Just route the engine coolant back to itself, and put another short piece on the two fittings coming out of the firewall. (so nothing crawls in there, etc) Then come wintertime replace the factory hoses and you'll have heat again. In fact, I'm still thinking about doing that, because honestly I only need my heat about 2 months out of the year.

    If your air is REALLY hot, it is possible that your diverter door has come out of adjustment or is broken. The above is just my experience.

    Edit: PS as far as I can recall there is no vacuum hose that would influence this, the vacuum connectors will open and close the various diverter doors that shove air one direction or another, but there is one big door inside that mixes the hot/cold and that was never vacuum driven.
    99 TJ Sport, RE 2" Spacer Lift, 325/60 BFG ATs.

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    i wish i could do that but then i would lose my defroster too. i need a warm defroster to keep the windshield from fogging during the rain. of course i could get some fog-x
    '98 TJ Sahara... i've done some things to it. lots of things. too many to list in a sig.
    The highlights being the one ton axles, the SOA and the tube work. discussion over.

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    JeepXLC, I live in Ft. Lauderdale and have never used my defroster to get rid of condensation due to rain. In fact, most defrosters only truely work if you have A/C, because they use the A/C evaporator to dehumidify the air. I think I'd go insane if I actually had to turn my HEAT on down here - I'd rather roll down a window and get wet instead. If you unhooked your heater core, you could still divert air towards the windshield, but yes obviously it would not be heated...

    Just my $0.02. PS if you search on my name you'll find a bunch of recent posts about my A/C install experience - it is hands down the best thing I've done to my TJ. Even with the top all the way off it's nice having a little bit of A/C when I'm sitting at a light in this 95 degree heat.
    99 TJ Sport, RE 2" Spacer Lift, 325/60 BFG ATs.

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    back from the land of JK 2k2wranglerX's Avatar
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    ok, mine's going to the dealership. I'm getting NO air temp control now. it's hot all the time. like fully hot. so back to the dealer it's going. anyone forsee any warrenty problems with my mods?
    03 TJ sport
    4" full traction long arm
    full skids
    solid industries 60
    4.88's, arb's, alloys
    kilby oba
    mastercraft seats.. etc etc etc

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    AdamLotz, its easier to go get 2 cutoff valves and put them inline to the heater on each hose, then you can turn the heat off and on as you need it, you can even use it to regulate the amount of heat. I had a semi once that had a busted heater control line, so I used the cutoffs to regulate the amount of heat in the cab, I would get it to where the heat was where it needed to be and would crack the windows if it became to hot and stuffy in the cab. also by blocking off the flow to the heater core your ac will cool much better.

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    -=- originally posted by 2k2wranglerX -=-
    ok, mine's going to the dealership. I'm getting NO air temp control now. it's hot all the time. like fully hot. so back to the dealer it's going. anyone forsee any warrenty problems with my mods?
    Wait, aren't you the one who did this post? new 180 thermostat, and now i have a check engine light, any ideas?

    The thermostat on your vehicle is not like the one in your house. You don't replace it with a colder one to get colder air in your car (jeep).

    I'd probably say you should put a correct temperature thermostat in first, so they don't charge you an arm and a leg to do that for you. Then, I'd address the problem. Probably a connection in the slider controls, most likely a loose screw or nut.

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    Roadkill, here is something I'm really not clear on:

    I'm not sure how the heater lines run in the 4.0. Can I just block them off on the engine side without disturbing the rest of the cooling flow? I had assumed that the heater lines were intented to have water actively flow through them, and that if you disconnected them you could have some problems if you didn't route them back to the engine... ?

    I guess I could take a look at my shop manual. Blocking them off does sound like a good idea (especially since I have brand new coolant in, and never need the heat here in S. FL) but I wouldn't want to do it if it could cause other cooling issues.
    99 TJ Sport, RE 2" Spacer Lift, 325/60 BFG ATs.

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    Rather than discussing how to isolate the heater matrix, why not fix the actual problem?

    On Wranglers with the rotary HVAC controls the blend door, that's the flap that controls how much hot air gets into the system, is operated by an electric motor. The fault can be with the switch on the dash, the motor, the wiring between, or the blend door could be stuck.

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    back from the land of JK 2k2wranglerX's Avatar
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    -=- originally posted by DEN -=-
    Wait, aren't you the one who did this post? new 180 thermostat, and now i have a check engine light, any ideas?

    The thermostat on your vehicle is not like the one in your house. You don't replace it with a colder one to get colder air in your car (jeep).

    I'd probably say you should put a correct temperature thermostat in first, so they don't charge you an arm and a leg to do that for you. Then, I'd address the problem. Probably a connection in the slider controls, most likely a loose screw or nut.
    i put the 180 thermostat in to try to help the electric fan. I'm not a moron dude. this isn't the first vehical i've wrenched on. But i didn't know if jeeps were like hondas and broke their climate control cables and stuff. that's why i was asking.

    as far as the correct engine temp thermostat. . . . as far as i'm concerned, i put the correct one in. I fixed what chrystler did wrong it runs at 210 anyway, the thermostat just opens earlier. . . .
    03 TJ sport
    4" full traction long arm
    full skids
    solid industries 60
    4.88's, arb's, alloys
    kilby oba
    mastercraft seats.. etc etc etc

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