rev up your engines, today I'm gonna talk
about a common car air conditioning problem and how you can fix it the
problem is this say the passenger side is blowing cold air but the driver's
side is not blowing cold air, now a car like this 94 Celica it's a simple air
conditioning system it doesn't have dual controls or anything it's got AC you
turn it on or off then it's often a very simple problem just being low on
refrigerant now this may be a 26 year old car but I've only had to add
refrigerant one time now here's an old broken AC compressor
all air conditioning compressors leak somewhat over time the fan belt spins it
spins a shaft the shaft has to have a seal on it if that seal was perfect it
would run dry burnout and all the freon would leak out, they all leak a little bit of
refrigerant and AC oil in order to lubricate that seal now in a case of
Toyotas it's often a very slow leak I mean I had to add refrigerant to
this thing once in 26 years so it's a very slow leak but when it leaks out
enough it will affect the performance of your air conditioner if you understand
how our air conditioners work it's totally logical the compressor
compresses the refrigerant it's hot then it pushes it to the condenser in the
front which gets rid of the hot air, hot air gets blown away then that gets sucked
into the evaporator inside the dash that expands and gets cool there then it's
sucked back into the compressor in an endless cycle and since most cars have
the evaporator on the passenger side if you're running low on refrigerant the
passenger side can still blow somewhat cool but by the time it makes it over to
the driver's side it's not cool anymore so just being low on refrigerant can
make it do that so if you know how to use AC gauges you can hook them up to see
if your low on refrigerant and if your are you can add some and if you don't you
can just pay a mechanic to check it it doesn't take five minutes and here's a
money saving tip guys are always trying to sell people stuff say your low on
refrigerant they'll say oh wow your compressor is leaking you need to buy a new
one before you spend a whole bunch of money if it's been years or if the
system never has had any refrigerant and first just add some refrigerant I've
done that on cars and sometimes they last five six years before they stopped
working to get in then you just fill them up once every five or six years
always start simple and work your way up and if you do add refrigerant if your
system doesn't have any of that leak dye a lot of them are made with leak dye but if it
doesn't you can add a little bit of the leak dye in to so then when it finally
leaves out you'll see the dye coming out of the area and you'll know which one is
leaking now many cars just have the single AC system leaving this relatively
new matrix it's got a single system called on one side not on the other odds
are you just low on refrigerant but if you have a more modern dual control
system where you control the left side and the right side independently like
this lexus then things can get complicated because here as you can see
you can adjust the driver's side from cold to whatever temperature you want
and the same thing on the passenger side you can adjust that too, now here of
course you're doing the level of sophistication all run by computers that
can make your head spin but basically here's how it works the computer system
take the inputs there's temperature indicators inside and inside the dash
are blend doors that open or close to a certain degree to make it whatever
temperature you sided here now of course a lot of its fantasy you put it on 69
degrees it's not gonna stay exactly 69 but you can make it soap one side can be
as hot as you want in this case will go too hot or the other side can be as cold
as you want in that case the passenger side it would
turn the duct to the heater open using the actuators that open the door so
you'd have hot air blowing here but on a driver side it would only open the
actuator for the AC system so cold air would come out here and you can guess
what happens with computer actuated systems when they break I mean thank
heavens this is a Lexus they hardly ever break so I don't have to mess around
with it but when they do break unfortunately you're gonna have to find
a guy like me that has one of these really fancy computers to access that
data to do bi-directional testing I'll show you how it works on this Lexus well
the beginning is easy it just plugs into the data port plugged in then we put on the
car and we're looking for stuff for the air conditioning system well the air
conditioning system on this particular one
it's part of the body system so we'll push body it's got all kinds information
I could join that the magnetic clutch is off now cuz they see just the cycling
and on a second they're not back on again
you get all kinds of data you can analyze and as various active tests that
you can do to not question you don't have one of these fancy scan tools good
luck trying to figure out what's wrong it's one of those blend doors is
breaking plus most of the time it'll be something like an actuator motor you
gotta take the whole damn shit a car apart to access it repairs can easily
top a thousand dollars on many cars these days of fun of those stupid little
doors breaks but it is another tip that might save you a ton of money let's say
you're having electrical problems the first thing I advise all my customers to
do is have the battery load tested and have the alternator load tested many
auto parts stores do that free you can even buy a quality thing to test it you
stop these days for seventy eighty dollars you know buy an expensive one
like this midtronics this thing was over eight hundred dollars and it was new
today you can get 60 70 $80 versions from other companies that work quite
well realize that all computer-controlled systems require a
steady accurate supply of voltage if the voltage goes too low or too high
squirrely things can happen if you're cold on one side hot on the other maybe
there's just not enough power going to the other side
always check the battery and alternator before you start spending a ton of money
doing computer analysis and turn the dash apart and here's another trick
let's say this side is blowing called and this sides blowing high well the
extra weird is dropping here sometimes just going back and hitting the dash really hard
if it's a stuck actuator a lot of times they'll unstick I've had some
customers that drove cars years that way when one went cold on one side and not the one side they give it a
good whack and it would start working and realize those stupid doors are
generally made out of plastic and they can stick as they age and if hitting it works
what the heck so now you know a bit more about car AC
systems and what you can do if you've got hot air blowing out on one side but
cool air come out of the other so if you never want to miss another one
of my new car repair videos, remember to ring that Bell
