taurus cooling problem

need some help guys.my daughter has a 2000 taurus with 3.0 ohv engine.got hot on her the other day she had it towed to her boyfreiouse.he is fair mechanic.plastic tank had hole in it replaced tank and refilled system with water.it will do fine as long as you let it idle normal temp.if you run it around 2000 rpms after a minuates will push water out of tank.i am getting this info over phone since she lives 120 miles from me.if it was a blown head gasket wouldnt it show up during idle?is it possible impeller came off shaft on water pump?any suggestions would be greatly apperciated.


thanks charles.

not sure if that year had air bleed screws in cooling system...but wont hurt to look
either around thermostat housing & or above w/pump
look for small stotted screw w/lock nut, loosen l/nut back out screw & bleed air out
good luck

got car to my house now.fans will only run with ac on and coolant temp sensor unplugged both fans. plug sensor back up fans kick off.sensor is new dont know which relays were changed think both high and low speeds.anybody got any ideas please post will try anything.

thanks charles

Have you checked to make sure there is no air left in the cooling system? I think Inafogg is on the right track. If there is not a place to bleed it, raise the front of car till the reservoir cap is the highest point in the cooling system. Take cap off and run it tonormal temp. Then go ahead and run it at 2k to get the air to pump out. Air will travel to the highest point.

Car has been in family for 8 years have never had problem with air in system.have changed coolant every year.there is power to fans but something signals computer to ground fans.i think it might be computer but dont want to wast money till i am sure of the problem.done the jumper wire at coolant sensor with no results.it has the 5 volts comeing to it.just cant figure out why the ground signal is notbeing sent from computer to fan.thanks for the reply if you have any more ideas would apperciate them.

Thanks charles

Have you checked the cooling fan relays? Go to https://www.fleet.ford.com/maintenance/owners_manuals/default.asp
and do=wnload the owners manual. Go to roadside emergencies and search for fuses. It will give you the location of all the fuses and relays.

Have owner manual.all relays have been changed out. All fuses are good.new temp sensors.just has to be wireing or computer.in some wireing charts shows a fan drop down resistor but cant find out where it is.dont know if that could cause this problem.if anyone has any ideas would apperciate them.will try and check out any ideas.

Thanks charles

Have you checked the operation of the Engine Coolant Temperature (ECT) sensor? Since both fans run (please confirm) when you unplug it, it would seem like maybe the sensor is not giving the correct signal to the PCM. The ECT reduces resistance as temperature increases, so shorting across the sensor like you did would seem like it should tell the PCM to call for fans....

The temp indicator in the instrument cluster is operated by a sending unit independent of the ECT so not having an overheat indication in the instrument cluster is not necessarily a sign that the ECT is functioning properly.

I don't have the factory service manual for the 2000 model year. If it's similar to the 2002 Taurus though, when the fans are to run in high speed the low speed resistor is bypassed, the relays put both cooling fans in series, and full battery current would be allowed to flow through the series motors. In low speed the two fan motors are in parallel so if one motor failed the other would still be able to function assuming the resistor is not open. It appears the resistor may be mounted either to the cooling fan mount or behind the fans on the engine block. You mentioned that all relays were changed out. In the 2002 model year this would consist of 4 relays (Engine cooling fan brake relay, Engine cooling fan relay, Low speed fan control relay, and High speed fan control relay). How many did you change in your car?

-Rod

Yes put in a new cst and new temp guage sensor.i might be wrong but thought if you turned on ac fans should come on but will come on with ac on and cst unplugged. Plug cst back up kills fans.i wasnt the one who changed the sensors just had a thought while posting this if he got sensors backward would that cause the fans to not work.mabey one of relays he replaced was bad. I think he changed everything at the same time.my haynes manal covers 96-05 and wireing diagram shows the ccrm which was changed after 97 down loaded a diagram from 2002 but think its a little differentthan 2000.if you have anymore ideas please post them.

Thanks charles

Do you have a multimeter or test light and understand how to use it? You might be at a point where you need to start checking for voltages at places.

I agree that with the A/C on the fans should run, with or without the CTS plugged in. But the CTS doesn't control any of the fan relays directly, it's all through the PCM.

-Rod

yes have tester and voltmeter.need to find out which pins on computer ground the fans.have searched but no information so far.wireing diagrams are kinda hard to understand. dont know where signal comes from to the computer pin i guess everything works in conjuction.i usually can figure this stuff out but this has got me stumped.there is usually the answer to most problems on this website it has sure saved me lots of time and money.theres some real smart guys helping people here.hope you have some more ideas.
thanks charles

This is still from the 2002 service manual. You might see if it matches us.

ECT Signal - pin 38 of PCM, Light Green/Red wire
ECT Return - pin 91 of PCM, Gray/Red
A/C Pressure Switch - pin 86 of PCM, Black/Yellow
Fan Speed Control relay - pin 46 of PCM, Light Green/Violet
Fan brake relay control - pin 28 of PCM, Light Blue
Fan relay control - pin 42 of PCM, Light Green/Yellow

-Rod

Do you know which pin sends the signal to ground to fans.would it be pin 42 for fanrelay control.have voltage on red or orange wire cant remember which one just checked one should have checked both.probely low and high speed relayswould send the voltage.just thinkingwhile writeing this.i will check pins tomorrow and see what i come up with.i apperciate all your help.

Thanks charles

The PCM sends ground to all four of the relay coils to activate the individual relays. The High speed and Low speed relay coils are grounded at the same time by the PCM. Fan motor #1 has a hardwired ground. Fan motor #2 is grounded via the high speed fan control relay, either directly (relay "off") or through fan motor #1 (relay "on").

If you'd like a copy of the PDF, send me a Private Message with your request and e-mail address. I looked at the diagram from EBSCO through our library for the 2000 model year and it matches the wiring from the 2002 factory service manual.

-Rod

When a fan doesn't operate, it's rarely the PCM the culpirit. The engine must stay hot for a long time before the fans activate. They never activate as soon as engine reach operation temp.

You said in post 1 that water spill out expansion tank when you rev at 2000 rpm. Have you checked the pressure cap at top of this tank? Maybe the seal of the cap or the cap is broken so water spill out from there.

havent worked on car last couple of weeks.but did find out if ac on have 13 volts on red and orange wires on passenger side fan and on one wire on drivers side fan.but fans dont work.took test light and checked black wire to fans from positive battery post shows not grounded would not light test light.ran ground wire from black wire at fan to battery ground fan still didnt run.this is confussing me. cause if wire up direct fan will run.have one fan wired through afog light relay with toggle switch where can run in city traffic but would like to get it working right.i appericate the diagrams that were sent to me but was alittle over my head.

thanks charles

test resistance at pins of the fan (harness disconnected). If there's no continuity, the fan motor is broken. test also continuity at ground fan wire. Maybe it's cut somewhere.

If you've connected a relay and toggle switch to manually activate the fan, I assume you did not use a double pole relay where you're providing both power and ground via the relay to the fan motor. Since you are probably just providing a power source to the fan, and it runs, that would suggest that you DO have a good ground to at least the one fan. The diagram I have for the 2000 model year varies slightly in the fan grounding schematic from the diagram in the 2002 Factory Service Manual. I'm inclined to believe the diagram from the 2002 FSM since the way the diagram I have for the 2000 is shown, both fans would be open to ground when the engine braking relay is in its rest position. This would suggest no fan motor braking could occur. It would also suggest that your toggle switch and relay would also not work unless you ran a dedicated ground wire as well.

Have you tried direct wiring both fans or just one? If you've only tried one, you need to try them both. In the low speed condition if you have one fan that is open circuit, neither will work until the high speed is called for.

Where did you connect your wire for your toggle switch and relay setup?

-Rod

thanks for the reply ididnt hook up the relay my daughters boyfreind who was working on it put it on.have it at my house now.he ran power to relay off fuse box inside so only power going to it with switch on.the ground he hooked up to fan cmes from battery ground post.he put a fused hot wire to relay to from hot post of battery i assume it powers relay and wire from inside attivates the relay.its really cold here now so it will be a few days before i work on it again.i checked power to high and low speed relays had poer there.but didnt have power to fan brake relay by looking at diagrams should be power there to.will do somemore checking when warms up a little.with your help i am sure we will figure it out i really do apperciate all the help.

thanks charles

It depends on which wiring diagram we go off of as far as if the fan brake relay should have power to it. The EBSCO diagram for the 2000 model year would say there won't be power to the fan brake relay until the low speed relay is closed. The diagram for the 2002 model year from the Factory Service Manual would suggest fuse F1.09 will provide power to the brake relay at all times. Have you confirmed fuse F1.09 (40A) in the Central Junction Box is good?

-Rod

I must apologize. I just took a closer look at the fan wiring diagram from EBSCO for the 2000 model year and it does NOT match the 2002 FSM diagram. I printed the 2002 fan diagram from EBSCO and it appears to match the 2002 FSM, it's definitely different from the 2000 model year diagram from EBSCO.

Is your daughter's boyfriend going to be visiting again soon? I can send you the diagram for the 2000 model year.

-Rod

I just checked the schematic for 2000 Taurus from EBSCO to see what you are both talking about.
Ok, you said in post #16 that you have 13V at both pins of passenger fan which is motor 1 I guess, right?
Ok, so you know that the low speed fan relay is activating and cooling fan resistor is ok.
Also the PCM relay is activating.
Also the high speed fan relay is activating.
Also the PCM is working.
Also the fan brake relay is activating or is broken, otherwise you'll get a short.
But you don't have ground at black wire of motor 1. So probably the fan brake relay's internal switch is blown. Or a bad ground in relay, we don't know.

Or you didn't test properly and the fan motor is blown.

So first, disconnect fan harness and test continuity between one of the power pin of fan and ground pin of fan. If it's good, remove fan brake relay and give 12V with jumper wires at coil pins of the relay. You should hear a click.
Then check continuity between pin 30 and 87, it should be ~0 ohm.
Then check if you have ground with test light at pin 30 of the relay socket's fuse box (key off).

checked contunity at fan pins had it at fan.stopped there wanted to check back with you on checking relay.would i have to put ground on pin 30 and hot to pin 85 and 86 to hear relay click.did check ground at pin 30 no ground there.i was just not sure on checking relay.this last diagram is easierto understand thanks for the help.

charles

You would check for good ground to the socket for pin 30. To check the relay you would apply power to pin 85 and ground to pin 86 (or vice versa - it's just a coil and not polarity sensitive), then check for continuity between relay terminals 30 and 87.

-Rod

Yes, ground in the relay socket in your power distribution fuse box.

http://farm3.static.flickr.com/2480/3554568885_630a8be494.jpg
This is an example, not a Taurus.

well we are makeing progress.done test on relay showed good.had no ground at pin 30 on harness.ran a wire from body ground beside battery where awire comes from battery ground post to body.spliced into black wire to pin.had ac on fans came on ran about 20 seconds and kicked off.had some extra relays changed out relay fans ran about 20 seconds kicked off again.put relay i took out at first back in same condition.do you have any idea whats going on.


thanks charles

Maybe the fans are only running as long as the compressor clutch is engaged. Watch the compressor clutch and see if it kicks out the same time the fans kick out. Unless the engine is up in temperature, the fans will probably only run while the compressor is engaged.

-Rod

wil get car up to running temp today see what happens.do you know where the ground wire for pin 30 comes from.have one on passenger side fenderwell with a couple of wires to it.what i did will not cause any problems will it.

thanks charles

well i believe we might have problem solved.with the new ground wire spliced in to wire for socket 30 of fan brake relay with ac on fans come on about every two minutes and run mabey 15 to 20 seconds and kick off.i am hopeing thats because it so cold outside.car wont warm up enough to check and see if fan will come on from temp sensor.if i unplug temp sensor fans will both come on and stay on till i plug back up.i thought fans would run all the time with ac on but mabey not in cold weather.if put jumper wire from ground to signal wire on ac high pressure switch fans stay on.switch could be bad just dont know.is this the way all this is suppose to work or am i just wishfully thinking.any suggestions are appericated.

thanks charles

Did you read post #27 above?

-Rod

fans have a different run time than ac compressor.they kick off while the compressor is still running.do you think that fans running with cts uplugged is correct? im not sure about any of this anymore.hope they are working correctly now.apperciate the help

thanks charles

As the coolant temperature increases, the voltage from the ECT decreases. Therefore an open circuit ECT would be effectively 0 volts, indicating a really hot engine, and the fans should turn on. So, yeah, I would expect that unplugging the ECT will result in the cooling fans turning on.

-Rod

mmm, no an open circuit will be 5V (ref voltage) which is more cold than coolant freezing point. I assume when the PCM detects open ECT, it activates the fan to prevent engine burning since it doesn't know the engine temp.

And yes, it's not abnormal that when A/C high pressure is short-circuited fan kick on, since when freon pressure is high, condenser' temp is high too.

Now with your ground wire, the fan kick on when coolant reach 210°F and over?

looking at the last diagram you sent me the ground for socket 30 of fan brake relay comes from g101 do you know where that is at?i have cleaned every ground i can find.is there a possibility that if they hooked up jumper cables backwards would caused the ground problem?i think this all started when the car was boosted.also does computer take in conderation the ambient air temp when regulating fans with ac on?sorry i am asking so many questions.guess i will find out for sure when warm weather gets hereif fans are allright.


thanks charles

mmm, no an open circuit will be 5V (ref voltage) which is more cold than coolant freezing point. I assume when the PCM detects open ECT, it activates the fan to prevent engine burning since it doesn't know the engine temp.



I agree.

You should try and find out the fan circuit logic to determine proper operation. My 99 Taurus fans come on (low speed) when AC is switched on, and does not cycle with the clutch until the car is going over 35mph. High speed fan comes on when AC high side pressure is over 250 psi, I believe. I got this info from my shop manual.

I turn on my A/C of my Taurus 2002 (engine cold) to compare too, my A/C compressor and my cooling fans don't activate. It's 23°F here. Both of my systems work very good in fall and summer.
So it's normal. It's write in owner manual that compressor works only when ambiant temp is 43°F and higher.

I don't know why your compressor works, but it's normal that your fans don't kick on.
Anyway, it's not good to use the A/C when it's too cool outside, you can damage the system.