i got a 93 taurus, 3.9 engine, automatic.. the a/c was working fine last
week and then it started to go off, just hot air, and on the ride home
it went from hot to cold.. it seemed that when i got caught by a red
light sitting at idle it was cold and then when taking off it would only
blow warm air... it did this about 6 red lights and i got home and only
blow hot air.. the compressor was not moving then.... the next day i
start it up and it blows ice cold air... later hot and no compressor
movement... i thought it might be the throttle position sensor and
checked it out and it works fine(the TPS).... i just get hot air now..
i start up the motor and pull off wiring to the a/c cycling swith(the
one that cuts off the compressor when you dont have any freon in it so
you dont burn up the compressor, and i bypass the contacts and the
compressor still does not pump.... i then check the a/c cycling switch
and get continuity on the two probes that come out so this tells me that
the a/c got a charge... it seems that the a/c is not getting any juice
for the pump (anything that i could have overlooked to check out on this
problem???) thanks for a reply...
Do you have manual or automatic climate control?
The service manual list:
dirty contacts clutch cycling switch
poor connection A/c clutch connector
clutch cycling switch connector
A/C cutout by ECA (engine control assembly)
You need to see if there is 12 volts at the cut out switch and clutch
connector with A/C on and go from there.
thanks for the info.. this is what i did today..
10 checked fuse(15 amp) under dash, OK.. then under hood checked the
wiring that goes to recycling switch- it read 12 volts... and i also
checked for continitity on the switch to make sure it was charged up..
then i followed the wires to the computer under the rad. cover.. same
color pink/lt. blue and they had voltage there.. i then check the
black/yellow striped wire coming out that goes to the a/c clutch and it
was zero.. i did a continuity test from pins to the back side of the
wires by shoving a thin straight pin into the wires and checking that
they is internal contact on the wires to pins... all ok...
all of this and Zero voltage to the wire that goes to the a/c clutch...
i then get disgusted and try something else: i cut into the wire that
goes from the computer to the a/c and run the wire that goes to the a/c
straight to the battery just to see if the clutch engages... it does and
the a/c is ice cold..... so somthing else it blocking the signal to the
a/c.... i dont want to buy another computer and find out that it did not
solve the problem... any suggestions???? thanks for a reply.. i tried to
find a cut off for the compress==somthing that will kill the compressor
when the pressure gets too high... like on some other cars so the
pressure does not go to high the a/c comp is cut off, but could find
nothing that does this,, its gotta be some sensor or the computer, but i
cant find out where... thanks again....
according to the trouble shooting Helm book you disconnet the harness to
the TPS and see if it will now work??? did that and it still did not
work... engine Overheat????--- engine ice cold in the morning...and
still no go with the compressor.....
Here is the signal flow:
12 volts at the A/C function switch assy.
When you turn the A/C on it puts 12 volts on the line
going to the A/C clutch cycling switch.
(It seems your OK up to this point).
From the A/C cycling switch, the 12 volts goes to the
ICM (integrated control module) mounted on top of the radiator.
The relay in this module is what actually feeds the A/C clutch with
I will have to research this a little more, but i think there is a signal
from the main computer (ECC) that has to be at the relay module along with the
A/C clutch 12 volts to engage the relay. This info is off my 90 manual, but i
think pin 21 of the ICM is the input from the A/C
cycling switch, and pin 23 and 16 drive a A/C clutch.
So, you have one of two problems.
1) the IRC is bad
2) The signal from the ECU is not correct to engage the relay.
This could be a bad ECU (not likely) or a sensor that
is not in range telling the ECU to turn the clutch off
(more likely if it has that capability)
I will see what else i can find.
Can you find a used ICM to swap out and try?
Have you checked the connector for corrosion?
Checked the grounds and mounting of the ICM?
Pull the top radiator shield off and check it out.
(Disconnect the battery if you disconnect the ICM)
OK, a little more info. Pin 22 on the ICM is the Wide open throttle
A/C cut-out switch. It comes from pin 54 on the ECC. This is the pin that if
could cause the A/C clutch not to engage if every thing else is OK. If this is
case, the question is what sets WOT on the ECU? Is it the TPS, or another switch.
More questions to answer. But i think this will at least point you in the right
direction now. Have you changed out your TPS?
man, thanks for the info on this,. i first suspected the TPS and tested
it for operation... via ohm meter and it seemed to be OK, for the range
it did.. i will take it off and take it to auto zone and get them to put
it in their tester??? but then i read in the 93 shop manual(does not
have too much electric stuff) that you remove the wires to the TPS and
then you can rule out the TPS as a problem as it is disconneded and will
not have the WOT causing the a/c to not function.. gonna read it again,
when aggravated trying to figure this out, i might be reading it wrong..
thanks again.. more help than i got out of the Haynes book and the Helm
93 taurus/sabel shop manual.. i just ordered the Elect. vacuum trouble
shooting guide for the 93 taurus/sable from Helm,inc..
thanks again, it sure would be alot easier to know whats inside the
module... i had a 83 mustang and there was a module in the kick panel to
cut off the a/c or let it come on?? the module was bad... took it off a
pried it apart.. one of the internal wires were loose/bad solder joint..
at the time the part was $46 my discounted price from the dealer....in
1984 dollars... a little solder and it was fixed...was hoping it could
be something like this.. a good int. module will proably cost me $150 or
more and still might not be the problem...
i finally fixed the problem... well at least it works now::::
took off the TSP and checked for voltage at the black/yellow stripped
wire from pin No. 22?(the one that gives power to the compressor
clutch... it had 12 volts on it.. gee i thought this must have been the
problem all along..(key on/the engine was running) i then put the TPS
wires back on the TPS and there still was 12 volts coming out.. Oh well
that was not it???/ i then kil the engine and cut the bypass wires that
i had on the compressor to test it out and figure i am just gonna put
the compressor wire back to the black/yellow stripe wire, but with the
engine running there is no voltage to this wire....i lost it..........
i then take out a pair of pliers and tap on the intergrated control
module and pull on all the wires to it and tap on the TPS module and
pull on all of its wires.... then i check the voltage at the black an
yellow stripped wire and get 12 volts...... so it is either the ICM, the
TPS or wires to or from them.. but it is working now(unknow for how
long)... i know the ICM has relays inside it, but i dont think they are
mechanical relays with point on it but probably electronic relays with
Itergragted circuirts in them.... so if i pop the ICM to look at it for
possible burned contacts,etc. i will not see them and with no test
equipt. other than a volt/ohm meter i cant test much in electronics...
thanks for all the help you gave i appreciate it... i will get some
contact cleaner and clean the contacts on the wires and make sure there
is continuity from the plugs to the wires....
only thing i can say is THANKS very much.. i did order the
Eletric/vacuum manual from Helm for $32, should have ordered it when i
got the shop manual years ago.. i first ordered the helm books back in
1973 when i bought a Grand Torino... got a whole box of books for
$35, then in 83 Got a box of books for my mustang/ and all the ford
models for $75.00,,, i guess they would want $400 now for a box of books
and it would only cover your specific model car??
Being the cheap skate i am, i will wait until one comes up on ebay.
Still not cheap, but better than a new price. I think i gave 30 to $35 for
the 93 taurus shop manual + shipping. I gave close to $45 for the Two
manuals for my S10.
Now, i do see these manuals on CD for cheap.
There are a few on ebay now:
i prefer the paper manuals. I like to sit down and study them over an over.
That's the only way i have found out (other than the news group) about how
to fix my fords.
There are a few shop manuals too:
There always cheaper when you don't need one.
check your low pressure switch. If it isn't working properly or is working
intermittently, it could cause this. That is the switch that tells the
computer that there is freon there, and allows the compressor clutch to
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