[Aaron M]

So I'm not done with this, I guess. Tail end of August, I was in construction traffic near Ramapo, NY, and the alternator light came on: the van died within about a minute. Yay. Good thing I got the windows up before the battery completely died. Two days and over $1800 later, the battery and alternator were replaced at Midas in Harriman. I don't recommend 'em, but that's another story.

Over the next few trips, I was still getting transient DTCs about the electrical system and I took it to the shop to have it checked: it turned out to be a shaft in the air compressor. When it kicked in, the draw was too much for the electrical and it threw the DTC. They replaced the shaft, or fixed the compressor, and I haven't seen the DTC since. It's running very nicely, except for the fans. It just turned 168K miles the other day, if it's useful.

On really cold days - 32º or less - the low fan might run without the high fan. Once the engine gets warm, even on cold days, the high fan will likely kick in. So the relays - which had been changed, above - don't seem to be stuck; the fuses seem to be Ok, but for some reason, the PCM wants to run the fans.

Bottom line: Can I get a code from the PCM to suggest why the fans are turned on? In ForScan, I'm already looking to see that the fans are on, but I'm curious if there's some information to suggest what triggered the "on" condition.

Also, @kazuo, on the diagram you provided in #5, what do the "17" and "10" refer to from the PCM? Thanks in advance.

 

[kazuo]

So I'm not done with this, I guess. Tail end of August, I was in construction traffic near Ramapo, NY, and the alternator light came on: the van died within about a minute. Yay. Good thing I got the windows up before the battery completely died. Two days and over $1800 later, the battery and alternator were replaced at Midas in Harriman. I don't recommend 'em, but that's another story.

Over the next few trips, I was still getting transient DTCs about the electrical system and I took it to the shop to have it checked: it turned out to be a shaft in the air compressor. When it kicked in, the draw was too much for the electrical and it threw the DTC. They replaced the shaft, or fixed the compressor, and I haven't seen the DTC since. It's running very nicely, except for the fans. It just turned 168K miles the other day, if it's useful.

On really cold days - 32º or less - the low fan might run without the high fan. Once the engine gets warm, even on cold days, the high fan will likely kick in. So the relays - which had been changed, above - don't seem to be stuck; the fuses seem to be Ok, but for some reason, the PCM wants to run the fans.

Bottom line: Can I get a code from the PCM to suggest why the fans are turned on? In ForScan, I'm already looking to see that the fans are on, but I'm curious if there's some information to suggest what triggered the "on" condition.

Also, @kazuo, on the diagram you provided in #5, what do the "17" and "10" refer to from the PCM? Thanks in advance.

What do the "17" and "10" refer to from the PCM?

Those are the Pin numbers for the PCM connector "C175B"
both fans should run, either in Low or High speed mode.
The PCM grounds those pins to activate the relays to control fan speed.

"I'm at 158k miles" you should flush the cooling system.

 

[Aaron M]

Those are the Pin numbers for the PCM connector "C175B"

Thanks!

"I'm at 168k miles" you should flush the cooling system.

I had the radiator and the fluid replaced as part of a TSB for orange fluid. That would count, right? (Not being sarcastic; just not sure if there's something more to "flushing" the system.)

 

[kazuo]

Thanks!



I had the radiator and the fluid replaced as part of a TSB for orange fluid. That would count, right? (Not being sarcastic; just not sure if there's something more to "flushing" the system.)

That's flushed;
I just check my cooling fans; started engine 60f day; cooling fans came on Low speed? Why the PCM commands the cooling fans On is beyond my pay grade. As long as the PCM is being feed good data and is not throwing any DTC's, let sleeping dogs lie.

 

[ranxerox]

The old fashioned belt driven fan ran all the time, What is the problem.

 

[Aaron M]

As long as the PCM is being feed good data and is not throwing any DTC's, let sleeping dogs lie.

I'd like to, and for much of this year I have, but in another post, you mentioned that your fans can draw almost 60 amps at high level.* That's 60 amps it's drawing from the alternator, all the time, and I wonder if it's putting my alternator at risk for early failure. It's failed once, at a very inconvenient time; I'd really rather not have it fail again. And since this wasn't a thing a year ago, I worry that it's actually a symptom of a deeper issue I just haven't discovered yet. I'm hoping someone will say, "Oh, yeah, I've seen this. It's such-and-such." No luck so far.

* https://www.fordtransitusaforum.com/threads/engine-cooling-fan-operation-question.92989/

 

[ranxerox]

60 Amps?! My early model transit (2016) has a 150 amp alternator and the entire van with the engine and all of the lights, Windshield wipers, Hvac fan On only draws 45 amps.
I think you are confusing fuse size with total power requirements.

 

[Tulta!]

Hello Aaron M I think I have a few important points to let you test.
There are two main reasons for the ECU to Command for the radiator fans in most non-hybrid vehicles.
# 1 Cool the engine coolant via radiator
#2 Cool the HVAC refrigerant via the Condenser

I'll assume that you monitored the engine coolant temperature and didn't find anything wrong.
The ECU has to turn on the fans if the the AC switch in the cabin is turned on. Have you switched the AC on?
this almost always starts the fans at Low Speed if the outside air temp is hotter than the desired ac temp. Rad fans turn on if the AC is switched on whether the engine is hot or cold.
You need a scan tool to discover whether the AC compressor is commanded on or off. Since you saw that the ECU had commanded the fans on, I would implore to you that you should check to see if the ECU has received a command to switch AC on. If the switching system for the AC has been stuck on, then the fans will also be on and no DTC code would be triggered. You have had a past record of an AC compressor failure which makes me suspect something may be wrong in the HVAC control system.

 

[Aaron M]

Hello Aaron M I think I have a few important points to let you test.
There are two main reasons for the ECU to Command for the radiator fans in most non-hybrid vehicles.
# 1 Cool the engine coolant via radiator
#2 Cool the HVAC refrigerant via the Condenser

I'll assume that you monitored the engine coolant temperature and didn't find anything wrong.
The ECU has to turn on the fans if the the AC switch in the cabin is turned on. Have you switched the AC on?
this almost always starts the fans at Low Speed if the outside air temp is hotter than the desired ac temp. Rad fans turn on if the AC is switched on whether the engine is hot or cold.
You need a scan tool to discover whether the AC compressor is commanded on or off. Since you saw that the ECU had commanded the fans on, I would implore to you that you should check to see if the ECU has received a command to switch AC on. If the switching system for the AC has been stuck on, then the fans will also be on and no DTC code would be triggered. You have had a past record of an AC compressor failure which makes me suspect something may be wrong in the HVAC control system.

Thanks for the reply. Unfortunately, the AC hasn't worked since we bought it - used at 72k miles, just about 3 years ago, now. I never turn on the AC because I already know it's not going to work. Summer driving sucks. However, last fall, maybe mid-September, there was a compressor shaft that needed to be replaced, and it did wonders for the battery / electrical system performance: the numbers are all spot-on, now, where the "actual" used to be much lower than "desired," according to ForScan. After the shaft was replaced, the shop guys said I should run the AC, when it's warmer, to see if it's actually working, now. But it's been cold, so I haven't. I had an appointment for this coming Tuesday to get the entire fan assembly replaced, because the shop guy said the low fan was making an awful noise (which I can't hear because I have serious hearing problems, but that's beside the point), but the front right bearings started dying on me near Monticello, this last delivery, and I was able to get it to Ford in Medford first thing on Friday, but they sat on it all day, so now it's out there, and I'm out here, and I'll have to go back to Medford to get it, when it's done. I planned to post a follow-up after the fans were replaced, whenever that actually happens; maybe it'll help others with this issue.

AC operation aside, it seemed like the fans did turn off and on, but that the levels they turned off and on were out of expected range. Like when it was 10-15º, the fans didn't kick in. Anything above 35º, and they did. We'll see what happens after the fans are replaced.

In the meantime, when I get the van back, how do I check the HVAC control system?

 

[Tulta!]

I use a Launch CRP129E for my scanner, I don't know if ForScan has HVAC controls capability.
Have you monitored the Coolant Temp Sensor during cold start? How long does it take to heat up? The gauges on the dash aren't a good measurement tool as the PCM's temp values.
HVAC controls can be monitored via the scan tool. Its difficult for me to point the finger at an out of range value when I can't see the module data stream. I'll give you some screenshots of my scan tool of what I am seeing on my Transit.
It seems like below freezing point 32 ºF, the fans won't turn on.

 

[Aaron M]

Have you monitored the Coolant Temp Sensor during cold start? How long does it take to heat up?

Yeah, coolant temp is one of the ForScan panels I have on my dashboard. On a cold day, it takes a few minutes, I'd say, to get up to "operating temperatures," which would be about 192º or so. Maybe a mile and a half to two miles of 30 mph in-town driving. Coolant temps haven't really changed from what I recall before I had the radiator and fluid replaced. In fact, I remember being slightly annoyed that the running temps were about the same; I was hoping for even better cooling.

It seems like below freezing point 32 ºF, the fans won't turn on.

That's a good point: I hadn't considered the freezing point aspect. Next cold snap, I'll keep an eye on if or when they turn on. I just recall watching the fans status while driving across state on that last cold snap, and I didn't see them on once during the out or back portions of the trip; I don't watch ForScan the entire trip, though. Transmission fluid temps were a little cooler than usual, but engine coolant temps were "normal": between 188 and 204 F.

 

[Tulta!]

compressor shaft

? I think that you mean the compressor shaft seal/bearing? I can't find a "compressor shaft" for the Transit.

 

[Aaron M]

? I think that you mean the compressor shaft seal/bearing? I can't find a "compressor shaft" for the Transit.

Off-hand, from memory, all I can say is it was a rotational part that was part of the compressor; fixing that was supposed to have gone far toward fixing the AC, which I haven't verified, yet. Even after I got a new alternator and battery, but before they fixed this part, I was getting spurious electrical system DTCs - P065B, for example - which completely stopped after the repair. I don't have the paperwork with the details for that repair job: it's filed down at the vehicle owner's office - I just drive it; he pays the bills - and I don't know where or how he files automative paperwork to look it up. Sorry.

 

[Tulta!]

You can see in the last half of the video that the "Air Conditioning Request Signal" is NO which is the important data point

 

[Aaron M]

You can see in the last half of the video that the "Air Conditioning Request Signal" is NO which is the important data point

After I get the van back from Ford in Medford, I'll check if this status is available via ForScan. If not, I can get the Launch unit through Amazon, I suppose.

 

[Aaron M]

Some follow-up: I got the van back from Steven's 112 Ford in Patchogue / Medford, and those clowns (watching my language, here) wanted to replace both hubs, and the entire front brake system (170k miles), even though this vehicle has regular maintenance, and just passed NY inspection two weeks ago, and my regular guys gave it their stamp of approval, knowing I'm happy to pay for any work that needs doing, and they could probably slip something extra past if they wanted. The pics Stevens sent showed rust on the rotors: I guess that was their reasoning. We pushed back, and in the end, they replaced one hub, one caliper, and both rotors. I didn't get to argue with them, so it wasn't my call.

However, it was slightly above freezing in Medford, and when I started the van, the low fan kicked in, and the high fan did not. At one point - I didn't run ForScan the entire trip - both fans were on: no A/C at any time, but warm air; not hot. By the time I got home, it was about freezing 32º F / 0º C, both fans were off. So the "frozen coolant" idea doesn't seem to hold. It seems more like the thermostat is working out of range: it kicks in lower than I'd expect. The new fan assembly is in at the local shop, but I have to reschedule the replacement. Probably next week. Stay tuned.

 

[Tulta!]

To clarify, when you say the low fan and high fan are you referring to the speed of the fans or only one fan spinning?

The correct way is that both fans move together all the time at the same speed and both are off when shut down. If one moves without the other, you've got an issue.
The diesel Transit is the only exception to this.

 

[Aaron M]

To clarify, when you say the low fan and high fan are you referring to the speed of the fans or only one fan spinning

The correct way is that both fans move together all the time and both are off when shut down. If one moves without the other, you've got an issue.
The diesel Transit is the only exception to this.

I don't believe that's true: the low fan can spin without the high fan. I don't think the high fan can spin without the low fan, though.

 

[Tulta!]

I don't believe that's true: the low fan can spin without the high fan. I don't think the high fan can spin without the low fan, though.

There's your problem. The fans aren't operating in the series (low speed)-parallel (high speed) circuit method. This is what you should be investigating. BOTH fans must be operating at the same time, regardless of fan speed. This must be brought up to your repair techs.

 

[Aaron M]

Turn off the defrost and the A/C and see if it goes off

Resolution - I think. I'm pretty sure this is an ID-10-T (idiot) problem, and operator error. Since fall, I've had the - wait for it - defrost switched on, even if the fan was set to 0. At some point, I needed more heat in the cab, and turned it to front vent. I left it there except when I really needed the front defroster. And, as the very first responder suggested, it was the defrost setting which turned on the fans. I ignored this suggestion because it seemed "too easy." There's where the ID10T - problem exists between seat and steering wheel - comes in. But, anyway, since I've set the heater to front vent instead of defrost, the fans don't run all the time. Feel free to fire the brickbats at will. I deserve it.