95 Escort overheating.....

Driving with the a/c on I noticed that it started blowing warm air then it would blow cold again after a 30 secs. or so and then repeat the process, I then noticed the temp guage at H! so I pull over and pop the hood.... cooling fan isnt moving? so i turn the a/c back on and still no fan? Took out the fan relay and plugged it back in and immediantly felt it click over, so i figured it was ok? I then drove home with the a/c off and when i opened the hood it was boiling hot at the resevoir while the temp guage was right in the center of C and H. I checked the fan by running power from the battery to the three prong plug and it worked. with the fan powered directly to the battery i then started the car (http://www.fordforum.com/m_13766/tm.htm#) and turned on the a/c.... same thing, cold for a few seconds then hot. Turned off the car and while disconnecting the wire from the fan I noticed it to be very hot (not a very high guage, but not thin either). Any help would be really appreciated.

Try this to make sure the relay is switching.....


http://users.adelphia.net/~bpaskevich/index_files/Relays.htm

Is the A/C clutch staying engaded the whole time, or is it popping in and out intermitantly? The A/C will only make cold air if the clutch is engadged.

If you hot wire the fan like you mentioned above, does it stop the over heating?

If the wire that runs the fan is hot, either the wire is too thin, OR the fan is using WAY too much power, which would suggest a bad fan motor, or somethig restricting it's ability to turn fast enough. The third possibility is that to voltage is way too high (But I doubt it).

Could also be a bad tempurature sensor, that would explain both the heat gauge not reading hot, AND the fan not starting up. Because if the engine thinks it not warm enough, it'll never start the fan.

this doesn't explain the hot fan wires though.

exactly my thoughts... either Fan motor, Relay or temp sensor, if it were the temp sensor wouldnt the a/c kick the fan on? Which it doesnt. I purchased the haynes manual and to be perfectly honest, its not as detailed as i would like it to be.... Guess i was hoping that the manual would tell me what the problem is !%&#*&! (joking). well im gonna take out the air filter housing to see if theres a problem underneath, someone mentioned to me that there are a couple relays there (high & Low side fan) and to inspect the wiring to the board there for any corrosion.... does that sound right to you? thanks for the replys and hopefully once I find the culprit this will help more pipe fitters like myself fix their cars!

it could be a short......the fan system is designed to constantly stay on if the relay fails or if the temp sensor sends bad data.

exactly my thoughts... either Fan motor, Relay or temp sensor, if it were the temp sensor wouldnt the a/c kick the fan on? Which it doesnt. I purchased the haynes manual and to be perfectly honest, its not as detailed as i would like it to be.... Guess i was hoping that the manual would tell me what the problem is !%&#*&! (joking). well im gonna take out the air filter housing to see if theres a problem underneath, someone mentioned to me that there are a couple relays there (high & Low side fan) and to inspect the wiring to the board there for any corrosion.... does that sound right to you? thanks for the replys and hopefully once I find the culprit this will help more pipe fitters like myself fix their cars!


Not the fan motor.
Why? With a direct connectio n to the battery you proved the motor is working.

Possibly the relay.
Why? Sounds like it can't make up it's mind when to turn on... but I am not certain which relay you are speaking of. There is the one in the engine fuse box, and there are the two in the fender well under the air cleaner.

Not likely the temp sensor.
Why? When the AC is on the fan is supposed to run at high speed no matter what the temp. It seems your problem is elsewhere. Remember that the temp sensor that controls the fan is different from the one that shows on your dash. A bad sensor does not explain why it doesn't work with the AC though.

When the engine is cold... when you start it up the fan should run for 10 seconds or so. Does that happen?

When the AC switch is on, do you have power at the fan? If not, trace it backwards to the realys in the wheel well then further back if necessary and see where you lose it... very possibly right at the switch. Is there any reaction at all when you turn the AC switch on?

I caution you not to drive your car anymore until you get it fixed... the heads on these engines do not like the excessive heat and you can have some very serious damage to your engine.

One other comment... when driving at highway speeds... even without your fan your car should not overheat. That would only happen at idle. If you are overheating at highway speeds you may have a plugged up radiator cutting off circulation. When is the last time the system was flushed out? I won't be surprised if you have a combonation of problems here...

You're right...just replaced the temp sensor (not the gauge, tested that one by unplugging n grounding to the chasis and the temp needle went up) and still nothing. Your question re: A/C, When I turn it on it blows cold briefly and the car will rev and shake a bit then will blow warm and the car will return to a normal idle. I also got the car hot enough to normally kick on the fan and tested the plug at the fan...Nothing! I can hear the relay I believe clicking while the a/c is going on and off (relay in the hood fuse panel) althogh I dont believe the two on the fender are doing anything..... can you give me anymore info on how to test the relays and test the relay locations for power as well. thanks p.s. no local autoparts stores stock either of the two fender location fan relays.

if you have a volt meter the link i provided at the top will take you through how to test them. You have to remove them from the car to test, a 9v battery will get it to open and close.

another easy way to test them, if you want to spend $20, is to get one of the cheaer code readers from the parts store... The code reader will do a diagnostic test on the relays... and one of the first things is low/high fan speed. If the fan doesn't operate with the code reader test... your relays (wheel well) are bad.

I think the clicking you hear when the AC is on is the cycling switch.... if you hear it clicking a lot, maybe your AC system is discharged.... that would explain why it won't keep up the cool air.

Yeah i did see the link, thank you. I found a new 9v battery and placed the clips one each on both "coil" points on the relay and all three relays tested like this clicked over then after removing the power source they clicked back.... is this telling me they work? or is the volt meter required? hence my little yellow digital VM does not beep... at least i dont think it does.

You could measure the resistance across the other pins when you conntect the battery to verify that there is not a bad connection. it should measure 70-100 ohms closed and near 0 when the relay is activated. Although i would assume that they are functional becuase they are clicking over.

When you first start up the car does the fan operate for about 5-10 seconds then turn off?
I believe, because of the way it is wired, that if the low speed relay is bad, then high speed does not operate either. I think the high speed is wired through the low.

I believe you said you bought a Haynes manual? If so... read in there about how to use a jumper wire to do a diagnostic test for check engine codes (this is the same as hooking up a code reader). When this test runs it should operate the fan at high and low speed... it may not tell you what the problem is, but it can quickly tell you what it is not by ruling out the motor and relays.

Try tracing the power from the AC button... follow it and see where you lose it.

When the car is started the fan does nothing... I pulled off the cover to the cooling fan relay in the engine fuse panel and it clicks over as soon as the car is started but the fan does nothing... shut the car off and the relay clicks back.

new temp sensor, same thing. tested relay in engine fuse panel and two on the fender wall, all tested good. hot wired fan to battery, spins. tested temp guage by grounding wire off of the sensor, good. temp gauge sensor works. fuse, good. conclusion.... mild to severe headache with occasional violent outbursts! ECU? SHORT? WTF? another thing is when i had the fan hotwired and the car started the a/c still did the same thing blowing cold then hot etc.

I suspect your AC problem is a different issue. You will need to test it to see if you are low on refrigerant.

Based on what you just told me... no fan when car started, and you verified the relay was clicking over... I would now susoect the 40amp cooling fan relay in the engine fuse box.

With the fan motor, high and low relays verified good, all that is really left is that relay in the fuse box... and the computer, but I seriously doubt that's bad.

Still wouldn't hurt to use a jumper wire or code reader just to verify everything. Check under "check engine codes" in your Haynes manual.

the 40amp cooling fan relay in the engine fuse box is the one that is clicking over when the car is started and then clicking back when i turn off the ignition...

Give this a try.... don't worry too much about retrieving codes since your light isn't on (is it?)

http://www.corral.net/tech/maintenance/eecivtest.html

When this test starts the fan should operate for a few seconds at low speed then a few at high.

If one works and not the other... suspect the appropriate relay. If both work, then you can troubleshoot wiring between your AC button and the high speed relay.

If neither works, and you are sure your relays are good, consider replacing the relay in the fuse box.

Some people eventually get fed up with this and install a toggle switch. Though that works, it is better to work through it.

Personally, though you already tested it, I suspect the low speed relay.
When your AC is on, test the light green wire coming in to the low speed relay for power. If power is there, test the yellow wire that goes to the fan for power... if it is not there, the relay is bad. If the light gree wire had no power, test the light green/ black wire going in to the high seed relay. If power is there, the high speed relay is bad. If there is no power there, go back to the engine fuse box.

I believe what you see clicking over in there is the ignition relay... I think the cooling fan fuse is part of the ignition relay... would have to go pop the hood to be sure though.

Just be systematic... either trace the power forward to see where it is lost of trace it backwards to see where it is found.

well since my VM is digital and not analog i tried the relay power test.... after plugging the red line into the light green wire on the low speed and the black grounded to the chasis with the a/c on and the car running it registered 0.03v, with the blk line still grounded i put the red line into the lt green/black on the high side and it registered the same. Itried this method with the relays both in and out to the same effect.

May have missed something here,lots of good info above ,but bend over left front fender and remove air filter box in front of battery and there is another fan relay mounted to fender wall that will have the color wiring your looking for.Hanes manual doesn't highlight that relay and ford hid it for a reason.

those are the high n low fan relays and if the wiring test posted above is correct which i assume it is... then that means im getting no power there, what tells those two relays to activate the fan? The ECU? The one thing you have to factor in is the a/c blows cold then hot and the cooling fan stopped working all together, doesnt do anything making the car overheat... and this is the key? They both happened at the exact same time. Even with the fan on a toggle the a/c is still acting up when i had the fan hot wired to the battery..... does that sound right?

I wouldn't worry about the AC blowing warm air until you can get it to run... if you get around to testing the AC pressure you can get more info on that problem.

Sounds like you don't have power even reaching the relays... power comes to the relays from the engine fuse box... your ignition relay has a swith that connects power to the fan.

In mine, when I push the AC button it lights up blue... if yours lights up you can feel fairly certain the switch is working right... so basically you have power at the switch and not at the relays... only thing in between is that 40a ignition/cooling fan switch in the engine fuse box.

The computer is a factor too... but I highly doubt a problem with it would be isolated to the fan... and I would expect you to have a check engine light if something was wrong with it too.

Just got back from the salvage yard after pulling all three relays and a ECU.... Plugged in the 20a cooling relay in the engine fuse panel and fan spun for 10 secs or so, turned on the a/c and fan kicked in.. a/c blows ice cold again. Dont know/understand why but this is the same relay which i removed the cover and seen it engage when the car was started... ignition eh? Any way the new relay seems to do the same thing but now the fan works as it should... havnt taken it for a drive yet but everything seems fine. Thanks to everyone who shared their knowledge (especially you MM), you basically had it right all along, good call.

Good news that the fan is working... but did the car stop overheating?

About the relay... I think it has a couple functions. When you turn the key and give it power those contacts engage, but as you noticed, there are 4-5 pins on the bottom... something within it wasn't working anymore.

Keep those other parts you got handy... you never know when you may need them ;)

Took her for a 45 min drive earlier and the needle didnt get beyond half way, ran the a/c for a while and no problems there either. AdvanceAuto took back the temp sensor i purchased so that basically paid for the gas and cost of the relays and ecu from the salvage yard. Only 74.5K miles on the little gas sipper.... hopefully shes got 75k more! The 1.9 engine dont have alot of horsepower (especially with the a/c running) but it sure does save me some $$ at the pump compared to my maxima with the 6cyl... but thats for another forum i guess.. ;) Thanks again, David