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Discussion Starter · #1 ·
Hello Fordists,

[Mondeo MK4 Titanium TDCi 2008]

I have a Blower Regulator in my hands, and no idea how to determine should I throw it towards the waterbirds or is it working as designed.
Story is:
  • no air con. Switch in console switches "A/C ON" but no cold air produced.
  • relay under the hood gets no signal (I mean control voltage, dunno what it is called in eng.).
  • shorting relay socket output pins engages compressor, engine tune lowers, cold air is produced within few seconds
  • I never had a diesel before, I now know they produce very low heat output thus never suspected this as malfunction: radiator fan never switched on during past my 8 months owning this Mondeo Mk4. Did a test run today with high revs/speeding --> no fan, but no high temp on engine either.
  • In yearly maintenance I asked to look for A/C errors on OBD. Garage recharged (yeah right) first, no air con, then they read P0691, "Fan Control Circuit Low/The Front Control Module (FCM) has detected a short to ground in the cooling fan relay 1 control circuit"
  • After getting the code I tested
  • blower 60A fuse: ok
  • measured full volts at the connector to regulator, no or less than 1V from regulator output connector (however, not sure if fan was supposed to be on)
  • blower blew well after feeding it direct 12V from battery
Ideas? Or just buy new blower regulator eyes closed and fingers crossed and... hope.
 

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Discussion Starter · #2 ·
Talking to myself. Local dealer here told that I can't buy the regulator only. It's the whole blower assembly I need to get. Luckily the price wasn't astronomical, 'only' 156€. Not going to pay that for testing if the original part had melted or not.
 

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Discussion Starter · #3 ·
Does anyone have access to mk4 wiring diagram? I'd need to find where the purple (signal) cable goes from the fan control box. I believe it's PCM/ECU, but don't even know where it is located. The signal might be light purple as well.
 

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Discussion Starter · #5 ·
The control wire from radiator fan I believe goes to the PCM. Check the main wiring loom in front of gearbox as the wires corrode in there
Hmm.. thanks for this info! Another garage here gave me new price for the blower assembly, 350€ (I had misheard above 150€) and he was kind enough to suggest not to buy a new blower to start with. Instead he was offering their services to replace cabling, which has been the reason for AC failures on some early mk4 Mondeos.
 

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Discussion Starter · #6 ·
Huh.. not easy. I located the ECU/PCM, I think I found the control wire from blower to ECU, at least colours match (pale/light purple). I get no reading on the meter, so either it's wrong wire or it's indeed cut. I pealed insulation a bit and ran another wire between blower and ECU, no A/C. As a bonus I got 'front lights malfunction'
but I hope that's due to front tyre missing and car is lifted.

Does anybody have wiring diagram for Mondeo MK4 2008 TDCi. Where does radiator blower control wire, pale purple with no stripes, end up (what box and what connector pin)?
 

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Discussion Starter · #7 ·
Okay, found the correded wire (in the junction of upper motor, gearbox & ECU/PCM). Fixed it and still no A/C. As a bonus this time I got check engine light. I have a theory that error(s) P0691 need to be reseted now for radiator fan to come back in business. Does someone know if this is true? And is there any possible way to reset OBD codes by driver?
 

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Hi
Just got my car's air con gassed, to find out the compressor does not cut in, nor does the radiator fan come on, this thread sounds identical to the problem i am having.
I have a 57 plate Modeo MK 4 2.0 petrol Zetec, with dual climate, it switches on an blows on all settings, heater works fine, there is power going to the radiator fan, there are 3 wires, one is purple/lilac in colour and much smaller than the other two, i think this goes to the ecu which seems hard to get to.
I see on this thread that the fault was found, but don't say how, any help would be very much appreciated.
 

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Sounds like a problem I'm currently having with my car. A/C used to work, but doesnt any more. its a 2010 (60 plate) Mondeo. Its been at Ford today, where gas has been checked and found the radiator fan was not running. Fan was checked and is OK when connected directly to 12v, so next they're gonna change the wiring loom. Fingers crossed
 

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Okay, found the correded wire (in the junction of upper motor, gearbox & ECU/PCM). Fixed it and still no A/C. As a bonus this time I got check engine light. I have a theory that error(s) P0691 need to be reseted now for radiator fan to come back in business. Does someone know if this is true? And is there any possible way to reset OBD codes by driver?
Hi Timo

Can you tell me how access the OBD and also how to reset them afterwards. Thanks in advance.

Brendan
 

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Hi,

disclaimer: I'm just a wannabe engineer so no warranty to my talks whatsoever
Regard my writings as hints for your troubleshooting actions.

Brendan, I think I should take photos to better explain but as I won't remove my wheels just for the sake of pics, I'll try to explain in written. Also, I'm not sure if left-hand side steering makes any difference to your situation.

My root-cause was the radiator's purple/lila control wire from ECU to the radiator blower regulator box being corroded just like hinted by Barrie M above.

There are three main things you do: verify corroded wire, fix it, reset Diagnostic Trouble Code.
This is how it went for me (left hand steering, remember!!):
(prereq: you or carage have read DTC "P0691" from ECU before starting this procedure)
  1. Remove air filter and it's black plastic "intake hose" that keeps us from freely seeing and accessing the wiring loom under suspicion. I hope it is found on the right side of the motor comp. also in right-hand-side-wheel cars.
  2. lift (and secure) car front
  3. remove left front wheel
  4. remove left fender(?) ("sisälokasuoja" in Finnish, Wikipedia: a fender, wing (British) (panel of a car which encloses the wheel area))
  5. at the front of the wheel, just behind this fender/sisälokasuoja there is a white box. This is the plastic cover for the ECU, remove the lid to access the 3 connectors
  6. the purple radiator control wire ends up in the first connector (shortest wiring loom) and (if my memory serves me correct) it's pin in 3rd line and row 6. As the actual pin is not exact here, you need to look inside the connector to see in which pin the purple wire ends up. You don't need to break the connector to see in. Anyway, the most helpful info here is the fact it's the first connector. There's another purple wire - according to my eyes - in the second connector which is wrong. I found out this via trial and error so you don't need to
  7. after locating the correct pin, measure with multimeter that the wire is indeed cut by connecting meter to the radiator end connector and to ECU end connector
  8. if no reading: measure again, verify you found the correct pin, ask a friend to make sure multimeter cable is having proper connection to the radiator blower regulator connector pin, use paper-clip or similar wire to ensure you have proper connection to the ECU end connector pin. And so forth.. you know the drill.
  9. if still no reading: take a break, you just may have found the root cause for your dead A/C (or overheating engine)
  10. Heading towards windscreen, look down from the area where the blower regulator is (right side of the engine compartment). Following the cable loom downwards you end up in near the gearbox. You see intersection where one end is the part you followed, another end continues upwards to top of engine, and the thickest end goes towards left wheel/ECU. My corrosion spot was exactly at the junction.
  11. remove electrical tape from the intersection area (also far enough from the ECU end and fusebox end). Open/remove the black plastic cover so you can see all the wires properly.
  12. locate purple wire. In my case the place where the wire was cut the purple wire coating had turned suspiciously light/white/pale, just like if you would stretch a plastic until it breaks in half. If you cannot find your corrosion spot here, you just need to peel wiring loom more as long as you find the place where purple wire is cut. You may need to do this further on the loom towards ECU as well as in fusebox direction.
  13. Fix it. I added some 10cm of new cable by soldering and insulating with heat shrink tube.
  14. measure again (step 7) and verify control wire is ok.
  15. secure wiring loom plastic shield again with electrical tape, connect ECU connectors, close lid, attach fender, attach wheel and wash car.
  16. easy, take a break and prepare for the IT part
  17. take your car to the local carage to clear DTCs (P0691), OR
  18. buy or borrow an ELM327 based OBD2 Bluetooth scanner, an Android phone and a piece of software called Torque (Free or Pro). This is just a proposal how to clear DTC and one which worked for me (I have an Anroid phone already). Clearing DTCs worked with the free version as well but I bought the Pro version (€3,50!!!) to respect the work of Torque developer.
  19. clear DTCs and enjoy cool cabin and engine.
That's pretty much how it went with my Mondeo. Sorry I didn't take photos. Guess I didn't believe I get it fixed..
 

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Thanks Timo
Can i ask if i need to go to the trouble of accessing the ECU if the wire corrodes at the junction, also i have no fault codes on my OBD 2, is the ELM327 a different piece of kit and would this show the fault code.
Thanks
 

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Thanks Timo
Can i ask if i need to go to the trouble of accessing the ECU if the wire corrodes at the junction, also i have no fault codes on my OBD 2, is the ELM327 a different piece of kit and would this show the fault code.
Thanks
In my opinion if your OBD2 (on-board diagnostic) reader does not show P0691 or equivalent, your wire isn't cut. If you still want to suspect corroded wire, part 1 would try to confirm wire condition, so my answer to you is yes, you need to go to the trouble of accessing the ECU to measure wire condition with a multimeter and both ends disconnected.

You say you have a petrol engine? Doesn't the radiator fan ever switch on? If I were you I'd go somewhere safe and put up a Grand Prix of my own to overheat (in safe limits that is) engine and see temp. gauge if it clearly exceeds normal position. If so, stop the car, open the hood and go see (keep your fingers away!!) if the fan is running. If no revolution at all in the fan we just might jump into the conclusion that your OBD2 reader does not pick up the DTCs properly. (I know you said fan does not work - this is just to confirm..
)

Again, I am no specialist here. I still would have assumed that any OBD2 reader would read P0691 if it connects to Ford ECU in the first place. ELM327 is just a chip used in cheap readers to access OBD2 interface with various protocols. As the cheap OBD2 readers are 'nameless' or otherwise funny branded, I guess people out in the wild Internet refers to these as "ELM327 readers" without make & model (mine was called "V-Gate"). You might also have a ELM327 chip in your OBD2 reader. Or not.

As it makes no sense for you to buy another reader, at least at this point, I suggest you to do same as I did: invest in DTC read in authorized Ford garage and take it from there. (or try to bargain the aircon gassing garage to read it for free).
Only thing I know for sure from my case is: Ford garage read DTC P0691, V-Gate + Android (ZTE Blade phone) + Torque Free read and cleared DTC P0691 successfully.
 

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Thanks again, i have never known the fan to come on, i have been standing in traffic several times, i have left it sitting in my garden for over an hour and never heard or seen the radiator fan cut in, yet the temperature inside always shows just below half way.
I just thought the fan would come on with the air con, maybe it don't, maybe the compressor is broke, but even so i would expect something to happen.
i know on older cars there was a sender either on the inlet manifold or the radiator, that when hot would power the fan, but this is to hi-tech, i think, i have also read posts where the fan relay can be wired, to power up the fan, but there are 5 pins and don't fancy my chances of bridging the correct ones.
I have just bought a V gate reader from China and will wait until it arrives and see if it shows a fault, in the meantime i will check the wire is intact.
 

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FYI, as I said, I am having this problem, but, with it being a company car, and still under warranty, its going to Ford next week to have wiring harness replaced

Regarding the engine temperature guage not showing much increase after being stood in traffic, I have checked mine (2.0 diesel btw) after a motorway run, then left idle in service station car park, with everything on / running (lights, radio, heated windows etc, for full load on alternator, and therefore on engine to attempt to increase temperature faster) and I have so far seen it increase from 80 degrees (normal operating temperature), to 110 degrees. I stopped after this point, but noticed very little movement on the temp gauge (none that I would even notice if I wasnt actually looking for it).

Also, I have been informed by Ford that the fan should be running whenever the A/C is on, so, no fan, no A/C. My compressor wont even kick in if the fan doesnt run
 

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Discussion Starter · #19 ·
PERKELE!

Excuse me my bad language but I just needed to let it out. My A/C died today, again. It's been rather cold spring/early summer here so after I - without a doubt - got cold air and saw with my own eyes radiator fan turning, A/C hasn't been used that much ever since. This week has been better so my wife told using A/C yesterday but switching it off after ~10mins when she felt too cold. So it worked yesterday.

Why me, why me? Today, at 24C on Convers+, I switched A/C proudly on, partly because of this thread activating again and only partly due to temperature. I hear a faint "clack", engine revs stall and dash lights dim for a fraction of a second. Self-satisfied smiling while waiting freezing air.. ... ..... No, it doesn't work.

New problem. I am sure compressor kicks in, or something which produces a "clack" sound kicks in.
  • I hear very faint, high pitch squeaky sound from dash air nozzles, or somewhere behind dash. First I think it's a sound from an open pipe and some mechanic sound source at the other end. Then it reminds me of home heat pump sound when refrigerant flows in the pipes - can't be as I get no cold air. Also refrigerant flow sound is a bit smoother than this - I think. Opening hood reveals I cannot hear this sound over engine sound. I repeat A/C on-off so many times that it's 100% sure sound only comes when A/C is on. In my earlier P0691 problem absolutely nothing happened besides console "A/C ON" text. This really is a new problem.
  • Radiator fan does not turn. OBD reader reports no DTCs stored. Why I hear the compressor clutch sound if blower isn't blowing? If my refrigerant now flies in the ozone layer, why on earth I hear above sound (so compressor at least is instructed to do something)? Wasn't there a pressure probe to stop function in case of too high or low refrigerant pressure? This fan part just doesn't fit in. I'd assume fan running if compressor clutch "clacks".
  • hadn't had change to test yet but could it be:
    - electronics ok, refrigerant pressure ok
    - clutch engages compressor
    - but clutch "jumps" or "slides" so that compressor doesn't actually turn but produces this odd sound I hear in the air vents?

I need help, please.
  • if compressor is stuck, how to tell or remedy?
  • if refrigerant leak, possible to tell without Ford-tools?
 

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It sounds like the gas is low, my car is 5 years old and still had 450 grams of R134a, i thought initailly that mine had no gas and thats why it wasn't working, until it was checked, i think it only holds 550 grams when full.
only other thing i ca
 
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