AC / Coolant Fan assembly issues, Im new to the group and would really appreciate some help

[Shubbs]

First off i guess from reading these threads my door blend actuators are all clickety click click clack, but they have been working, just noisey. so the other day my ac stopped working while i'm at idle like at a stop light then works fine when driving. took it to a garage and they confirmed it was a bad fan assembly and a subsequent blown fuse but wanted to charge me a fortune to fix. so i didn't get them to do the work and got the car back from them. Now after i got the car back from them the ac isn't working AT ALL after they messed with it, its hot when im driving and hot at idle or a stop light. So i went ahead and changed out the fan assembly (because i knew it was bad) and also put in new fuse myself, the fan works when i jumper it in the fuse box, the wiring is good the fuse is good but the fan wont come on. I know for sure the ac clutch kicks in because i have tested that and can see it coming on and off when i turn the ac switch in the cabin on or off. So right now i have no ac, the clutch and compressor seem to work, the system pressure looks good, the fan is good (new) and all ancillary (relays and power) appears to be good but fan still doesnt come on and my ac is friggin roasty toasty all the time now, so what have i missed and where do i need to look next? any help or pointers would be appreciated. 100F here in Houston right now so any life savers are welcome.......thanks

 

[scotman]

It sounds lke a defective thermostatic fan switch. About $50 plus labor.

 

[Shubbs]

It sounds lke a defective thermostatic fan switch. About $50 plus labor.

Thanks for the tip scotman! where abouts is the thermostatic switch located in the engine bay and what is its operation? Trying to understand how this thing (ac system and fan assembly) is supposed to work. I remember before the fan went out it was on pretty regularly so i hope this is the problem, would be great to get it fixed. Im sure i will be able to pick one up at one of the auto shops and change it out myself.

 

[scotman]

Thanks for the tip scotman! where abouts is the thermostatic switch located in the engine bay and what is its operation? Trying to understand how this thing (ac system and fan assembly) is supposed to work. I remember before the fan went out it was on pretty regularly so i hope this is the problem, would be great to get it fixed. Im sure i will be able to pick one up at one of the auto shops and change it out myself.

You probably should let an A/C shop figure out what exactly is the problem. The TFS is the coolant temperature sensor for fan operation. There is also a pressure switch in the a/c line which could also be a culprit in an inop a/c fan. The a/c pressure switch is also not expensive. But, it requires that the R134A refrigerant be evacuated, captured and then pumped back into the system. That takes some special equipment to pull off.

 

[Shubbs]

ok so i changed out the coolant switch below the coil pack. No change, also bought a scanner and getting the two codes, P0480:00-28 Fan 1 control circuit, and P0645:00-28 Air conditioning clutch relay control. Both codes are "historical" ie this is what the probelm was before i changed out the fan assembly and topped up the freon. Compressor Clutch clicked on and worked fine after i topped up the freon, which tells me the a/c pressure switch was working fine because it was previously holding the compressor out because of low freon.

The thing is my fan is not coming on during normal operation. I did a test with the scanner OBDII port and the fan comes on and comp clutch kicks in as part of the test. They work fine, so something is holding the fan out while in actual operation. Tested the ac system with manifold gauges and the pressures indicate the TXV is good, and that the compressor is on the way out, as the low side is high and the high side is low, but that still doesn't explain the fan issue..... any ideas?

 

[scotman]

I think that you found the problem. That compressor isn't "on its way out". I believe that Elvis has left the building. The compressor is not compressing anymore.

 

[Handy Andy]

Time for a new pump - Clutch and assembly is now working - nice recovery, unfortunately, when FREON is gone the oil that is left is not enough lubricity to maintain that diaphragm that pumps the freon into the restriction "nozzle" forcing the expansion and subsequent cooling (heat exchange).

The system is designed to stop the pump from cavitating with no lubricant in it nor fluid (your lack of pressure) - but by then the system is dried out and the pump just needs as rebuild - not for kids though - it's a bit more involved.

 

[Shubbs]

I think that you found the problem. That compressor isn't "on its way out". I believe that Elvis has left the building. The compressor is not compressing anymore.

Yeah after testing today I now know I need a new compressor (which explains why it's not cold) but that doesn't explain the fan assembly isnt coming on.......

 

[Shubbs]

Time for a new pump - Clutch and assembly is now working - nice recovery, unfortunately, when FREON is gone the oil that is left is not enough lubricity to maintain that diaphragm that pumps the freon into the restriction "nozzle" forcing the expansion and subsequent cooling (heat exchange).

The system is designed to stop the pump from cavitating with no lubricant in it nor fluid (your lack of pressure) - but by then the system is dried out and the pump just needs as rebuild - not for kids though - it's a bit more involved.

Yeah system has freon, clutch works, compressor not good(found out after testing today, which explains why it's not cold), system holds pressure and the high and low equalize after it's shut off. So no leaks and TXV is good. Still doesn't explain why my fan is not running......

 

[Handy Andy]

You did check - swap the relay into another slot to verify the relay is ok?

Then more than likely the issue is during the diagnostics the relay wiring might have failed...

Recheck your fuses - they may have blown one in error. OR to help in the diagnosis - removed one and never put it back in.

I mean, really check your fuse box, for they may have removed a fuse and if you don't see two open terminals (the use of a strong light and your owners manual - help here) - to locate ALL the fuses and make sure the A/C one is installed and working.

Else locate the relay and using a DVM - check for SIGNAL on the coil terminals side of the relay. Engage the AC and turn it off - see if you have anything - else the wiring is then suspected.

 

[Shubbs]

You did check - swap the relay into another slot to verify the relay is ok?

Then more than likely the issue is during the diagnostics the relay wiring might have failed...

Recheck your fuses - they may have blown one in error. OR to help in the diagnosis - removed one and never put it back in.

I mean, really check your fuse box, for they may have removed a fuse and if you don't see two open terminals (the use of a strong light and your owners manual - help here) - to locate ALL the fuses and make sure the A/C one is installed and working.

Else locate the relay and using a DVM - check for SIGNAL on the coil terminals side of the relay. Engage the AC and turn it off - see if you have anything - else the wiring is then suspected.

Yeah I tested the relays and fuses individually and swapped them around. Nothing bad there, I tested the wiring and even jumpered the relay pins at the fuse box everything works fine, and I even ran the diagnostic test with all fuses and relays in from the obdii, the fan kicks in and works fine just by using scanner in obdii port. The fan just doest work in normal operation ie when car is running for some reason. It's like something is either holding it out or not switching it on when required. Ran car and used the hidden menu to measure the coolant and it read up to 210F today and it still didn't come on........

What temp is the fan supposed to come on at? Could the low pressure on the ac high side be holding it out for some reason, possibly on temp or pressure?

 

[Handy Andy]

Er, no, they run two different relays -

(Added: In specific models, with bigger/Turbod' motors) There is a high-power resistor (low speed relay) designed to drop or lower the speed of the fan so it's quieter and makes the fan run to keep the exchanger and radiator from fighting each other while the AC is on (heat from one going into another) (ED: The Fiestas' 1.6L does not use LOW speed but the 1.0L DOES) so this raises another issue of wiring "quality" - this is an older car so if some of the lower powered sensors are not communicating back to the PCM - it just sits there - to me this is beginning to sound like a wiring issue more than sensor issues.

This may be a "continuity" problem.


It's a three terminal - so if the values are not in range - have to fix that.

But that doesn't do you any good if the wiring back to the PCM is causing the problem of OOR (Out Of Range)

The continuity problem.

Another mess to add to this...

Look carefully...



There are "Variants" so the point to point wiring, if it is not in "error" - no changes - it worked before - so if no changes and all things being equal - the color code - one of them should match your car - the pins to the PCM are different - so you know.

 

[Handy Andy]

IF all the testing shows the above seems to be working, then the Climate control system is next...

 

[Shubbs]

Er, no, they run two different relays -

There is a high-power resistor (low speed relay) designed to drop or lower the speed of the fan so it's quieter and makes the fan run to keep the exchanger and radiator from fighting each other while the AC is on (heat from one going into another) so this raises another issue of wiring "quality" - this is an older car so if some of the lower powered sensors are not communicating back to the PCM - it just sits there - to me this is beginning to sound like a wiring issue more than sensor issues.

This may be a "continuity" problem.
View attachment 6629

It's a three terminal - so if the values are not in range - have to fix that.

But that doesn't do you any good if the wiring back to the PCM is causing the problem of OOR (Out Of Range)

The continuity problem.

Another mess to add to this...

Look carefully...

View attachment 6630

There are "Variants" so the point to point wiring, if it is not in "error" - no changes - it worked before - so if no changes and all things being equal - the color code - one of them should match your car - the pins to the PCM are different - so you know.

So where exactly is this pressure transducer? Is this the same one (pressure switch) that holds the compressor out if refrigerant is low? Pretty sure I can read the high side pressure on the on the obdii scanner and it reads ok. I'll post a pic of what I can read on the scanner later so you can see what I see. Maybe I've missed something.
Same with the climate control system, I can read and see the switch and the call for the compressor to come on. All that works and can confirm it with the scanner on live data. It's just doesn't make sense.........

 

[Handy Andy]

The pressure switch is the same (but the PCM connector location is not) so if all else is correct, the pressure switch might have it's terminals pinout different than the OEM one - kinda hard to see without a DVM to check the pin-for-pin - and the wiring to the PCM also - I would suspect the Climate Controller is not communicating or the wiring of the pressure switch is suspect (still)



That low-speed resistor - you may not even have it - requires a LOW-SPEED fan relay and you didn't specify if you had 1.0 EcoBoost (1.0L) or the 1.6L N/A - so presumed 1.6L - but it needs to be said for Climate control can be Auto or Manual type.

The 1.6L one has none

 

[Handy Andy]

Pay particular attention to this one because of a swap in switch may mean continuity issues!

Note Pins used by PCM also for TYPE of motor


So where exactly is this pressure transducer?

On the bottom of the Radiator, right by the "condenser" core and Dryer tube, this is where the oil and the FREON collect and is the lowest pressure point in the system - by the AC compressor and right across from the Serpentine belt - on the front radiator shroud and holder.

 

[Shubbs]

yeah car is a 1.6L fuel injection, TiVCT, manual transmission, fiesta sedan. plugged the scanner in again tonight to show you the ac signal request and compressor command etc is good and of course it wasn't working now. The ac request is still good which means ac switch in cabin is ok, but the compressor command is now not working so I must have a refrigerant leak on top of the bad compressor. i topped it up the other day and as soon as i did that the compressor command came on and the clutch kicked in no probs. So right now i know the compressor is bad so i'm going to go ahead and purchase a new compressor, drier and I think it actually comes with a txv also. So once that arrives that will remove all the ac questions but there is defo something not right with the fan, so the fan is still a big question for me.

what generates the call function for the fan....see big red box? Is that direct from the PCM? How do i determine what inputs affect this to output the fan on? im pretty sure this is the diagram of mine as the two input wires to the fan in the car are the GN-WH and BK-GN. only one of each.

 

[Handy Andy]

Locate and read this thread...
Ford Fiesta Compressor not kicking in | Ford Fiesta Forum
https://www.fordfiesta.org/threads/ford-fiesta-compressor-not-kicking-in.8771/

See below...

 

[Shubbs]

Thanks! Pretty sure I know what the issue is with the ac compressor etc. my problem is the fan not coming on. The new compressor and stuff is due in within the next couple of days. Will report back once I have all that changed out. Either way the ac not blowing cold is the bad compressor, but the fan not coming on for engine over temp or when you click the compressor on is a little strange. Would have assumed the fan would have come on as soon as compressor is turned on.

 

[Shubbs]

Locate and read this thread...
Ford Fiesta Compressor not kicking in | Ford Fiesta Forum
https://www.fordfiesta.org/threads/ford-fiesta-compressor-not-kicking-in.8771/

See below...
View attachment 6656

Ok so I replaced the compressor, TXV, and the drier, sucked a vacuum to the 30hg and let it sit for about half an hour. No signs of leaks, gauge didn't move. After that I pulled a vacuum for 45 minutes to dry the system out. Next, turned car on with ac request etc. Of course compressor did not kick in because no refrigerant yet. Next I added R134a and when reached the required pressure, the compressor kicked it. About 50ish psi on the low side. Then the high side spools up and reads about 100psi. What is the high side pressure supposed to be? Is the 100psi correct? If so, the new compressor appears to be working, as does the pressure switch or it would have turned compressor on and sucked the clutch in if I didn't read the pressure.

So, during all this as expected the radiator fan did not come on at all. While I had the old compressor out I went ahead and changed out the thermostat since it's tucked behind the compressor, wasn't sure if it was bad or not but changed out anyway. So new thermostat now also in car along with new coolant switch on the head under the coil pack. The AC is NOT blowing cold in the car when driving nor at idle. Thing I have done and tested below.

1) previous fan assembly was bad. Changed out and installed new fan. New fan is good, tested with jumper.
2) previous 40A fan fuse was bad. Now got new one.
3) previous 10A fuse is good. Tested with continuity.
4) fan relay is good, removed from car and powered up and tested continuity thru the switch side of relay. Also switched relays to test if bad and somehow just acting wierd. No change.
5) tested wiring to fan assembly by jumping relay contacts at the fuse box. Fan Works as expected.
6) ac request from climate control works as I can read it from obdii scanner and status changes as button pressed on and off.
7) tested fan assembly by running obdii test. Fan powers up while everything connected properly in the vehicle and then shuts off after test. Which I assume proves the wiring to and from the fuse box.

So what the heck have I missed here?? This is beginning to drive me friggin nuts!!! Along with the 104F heat of course.