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terpam
New User
Feb 23, 2009, 10:52 AM
Post #1 of 7
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Floorboard heat only
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Hello to all,
I have a 1985 Chevrolet S-10. 6 cly. with A/C (compressor is out). In the truck I only get air blowing out at the floorboard. The blower switch is new as is the control unit (that switches where the air is suppose to blow and the temp. slider) But it only blows out at the floorboard...good I might add. I have been told it might be a vacuum hose disconnected but i cannot find a diagram even in a Haynes book. Any ideas?
Thanks, Terry
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 23, 2009, 12:08 PM
Post #2 of 7
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Re: Floorboard heat only
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Hi Terry - some guessing for this:
Usually vacuum controlled ducts will default to defrost mode vents when broken. Chances are this has a stuck diverter door and if you can find the arm exposed out of the distribution box and move it by hand it might snap out of it. Wild guess is that THAT mechanism (vacuum controlled? May be electric but doubt it) is over gas pedal on driver's side.
Were "new" controls really new or new to this vehicle?
T
Ps: Compressor out shouldn't effect this at all.
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terpam
New User
Feb 24, 2009, 6:16 AM
Post #3 of 7
(1829 views)
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Re: Floorboard heat only
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Hey Tom,
My mechanic found an unplugged vacuum line but could not find where it went. So he spliced into an existing line and it does blow through the various levels (although at every setting it still blows out strongest at the floorboard) but it still isn't strong.
Terry
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 24, 2009, 7:10 AM
Post #4 of 7
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Re: Floorboard heat only
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Excellent!
OK: The loose hose originally should have gone to probably an actual manifold vacuum source (use a "T" if adding into existing other hose) that might have been on what's called a vacuum tree and now plugged off for some reason unknown. these had a bunch of vacuum issues even when tons newer!
Vac tree is like that or some thing that screwed into manifold and was multi-functioned.
Then the hose would go to a vacuum ball (probably plastic with breakable nipple - about the size of a softball or larger hidden usually on passenger's inside fender area) which stored vacuum to hold ducts when no vacuum was available like when going up hill, accellerating or for a while with engine shut off. There's a one way check valve on ball or in line you could get anywhere if missing and would work without it but default to defrost going up hills - amusing for company??
At the age there could be a ton of gunk in by blower motor and you might even get a shot at a door to see if it moves ok. For A/C there's a choice of inside or outside air and just outside air doesn't give as much air as a mix or just inside air - AKA Recirc = recirculate = MAX. Max is really for a/C only - not heat only mode.
Blower motor is fairly easy to remove. Memory gone (back in a few) - ok - I think just 5, 1/4" bolts hold the whole thing to the distribution box underhood, pass side firewall and one slightly larger bolt for a ground = 6 in all.
Whole motor and squirrel cage comes out as one for inspection or cleaning.
View while attached.
View when removed with squirrel cage attached.
OK: Squirrels can't fit and other critters can't read so they make nests and other junk gets in there which will greatly slow down airflow. Carefully vacuum cleaner it out or use compressed air if that works better. The cage doesn't really catch junk - it passes to plug the air path or if real nasty can prevent diverter doors from proper operation.
That isn't that difficult to check and clean and may be the flow issue. Takes 1/4 drive little sockets to get at the bolts and then fanagle the unit out intact - little snug to do it but does come out intact,
T
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terpam
New User
Feb 24, 2009, 8:18 AM
Post #5 of 7
(1820 views)
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Re: Floorboard heat only
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Tom,
Thanks so much for all the good info. I'll check on the things you recommended. The tight spaces may be difficult, but I can try. The motor could probably use a good cleaning and lube. Thanks so much.
Terry
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Feb 24, 2009, 9:15 AM
Post #6 of 7
(1817 views)
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Re: Floorboard heat only
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There are 1/4" flex drivers like this (hard to see) but they are a cable if you will that goes around obstructions. You can get just one as an extention for any driver (ratchet) or (1/4" screwdriver style) and put the little sockets of need on the ends will get at this with little trouble. Going back hold the bolt with a thin strip of duct tape till it starts or some may be magnetic. Just check out funky tools at parts stores or even dept stores for one - handy stuff.
The motor isn't serviceable on these. You could try to put ONE drop (oil) where you see the shaft of it with a maybe for some help. They are sealed and near impossible to service DIY. Whole things don't cost all that much either.
BEWARE - the nut that hold that metal or nylon squirrel cage on MIGHT be reverse threaded so don't touch it if you don't have to. If it breaks the motor is junk
Taxing my memory again but the wires to the motor and a ground need be in good shape where they connect. Simple sandpaper and a drop of oil or WD-40 on connection can make them work better.
Know that the flare of that assy must be ground and may have an "L" thingy to attach a ground wire and that one bolt is NOT holding it in place - the other size ones are. If you can't get them all back in it will still work with most of them - laugh! Then when you get the right tool you can put it back in later. If you get there and replace - don't overtighten those little bolts - snug is enough. They are self tapping like wood screws into plastic not machine threaded to metal - it's ok you could go find a bigger one.
This isn't that hard as things go but anything can be without some tools to get at stuff.
YOU don't have to do this at all as it's just on the maybe list to make it better or perfect - not a sure bet that it's causing any issue.
Good luck with it. I like this vintage of S series Blazers - had an 84 as just a plow vehicle that was mechanically just right for that but rusted badly! That didn't have A/C at all - perfect for the extra room for plow hydraulics for what I needed it for. Nice strong chassis on those, and most things pretty straight forward to work on!
T
Ps: You didn't ask - but you can get at the speedo cable thru the speaker in dash if you need to lube it! Just a trick you may come to need!
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terpam
New User
Feb 24, 2009, 9:23 AM
Post #7 of 7
(1811 views)
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Re: Floorboard heat only
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"If you can't get them all back in it will still work with most of them - laugh!"
Everybody knows that most items contain extra parts. When I work on things there is always an extra screw, nut, etc. left over! It's amazing the extra screwholes these people put in things!
Terry
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