During our present cold snap (high around 0 F) several things have been happening. The most annoying is intermittent operation of the cabin heater pump when in EV mode. There appears to be no rhyme or reason as to if the cabin heater pump will run when I'm in EV mode. This is with a fully warmed up vehicle. On top of that switching the heater control to the 'red zone' (heater/defrost) doesn't force the ICE to start up. That can quickly lead to a chilly wind blowing on my feet while sitting at a stop light. My only recourse has been to turn the fan to off.
Anyone seen this happen before?

 

I know that the system won't run the A/C when the temperature is below freezing, but the red settings are still supposed to keep the ICE running.

 

That's what I had understood from reading various places.
I understand the A/C won't run at below freezing temps (and zero F certainly qualifies there).
As to the ICE running when 'in the red zone', the owners manual says

"Note: With the climate system set to (Max A/C or defrost or defrost/floor) mode, the engine will typically run continuously, reducing fuel economy"

(my bold emphasis on the 'typically').

Like I said, it sure gets cold when it decides to 'non-typically' NOT run the ICE when it's at or below zero out and I'm 'in the red zone'.

 

Back in my years in MT a piece of cardboard to partially block the radiator airflow would help...but that clearly doesn't apply in your case. You might try finding a way to force the system into recirculate mode but be aware of the DANGER in that, cabin Rh rising to the point of windshield fogging.

 

This is with a fully warmed up vehicle.

Most modern day automatic climate controls systems will switch the system to fresh inlet airflow at any time the A/C is off or disabled. Fresh, 0F, inlet airflow might be difficult to get up to a human comfort level using 180F engine coolant.

I know the system is drawing in that 0F air, but when the ICE is running and circulating that 180F engine coolant I get plenty of heat from the vents. The problem is w/o the coolant circulating it doesn't.

On top of that switching the heater control to the 'red zone' (heater/defrost) doesn't force the ICE to start up.

"fully warmed up.." Assuming the engine coolant is already at/near 180F why would firing the ICE up be of any help?

Because with the ICE running the coolant is circulating. In EV mode it doesn't circulate if the cabin heater pump isn't running, which is what the whole point of my post was. But since you don't own a FEH and didn't read my post completely you wouldn't know what I was talking about.

I'm starting to agree with several others on this board. Your posts are worthless!!

That can quickly lead to a chilly wind blowing on my feet while sitting at a stop light. My only recourse has been to turn the fan to off.
Anyone seen this happen before?

 

I just had the same problem with my '05.

https://www.greenhybrid.com/discuss/...ev-mode-28507/

It was intermittent but only for a very short time. Then it quit working altogether. I brought mine in to the dealer and they replaced the "heater coolant pump". It was under the extended warranty so it only cost me the $100 deductible. I asked the service writer what the repair would have been if I had paid for it and he added it up to be about $500. Looking at the paperwork that they kept, it looks like their price on the part was $212. The part number they installed was 6M6Z 18D473 AA Pump Assembly.

Good luck.

Found the part here for $157 http://www.fordparts.com/Commerce/Sh...t=6M6Z18D473AA

 

Also check www.silverstatefordparts.com. Looks to be $111.20.

 

I was about to answer this original post by telling US035976 that this is NORMAL... My '05 has been doing this as long as I can remember... I thought it was normal! I drive down a hill every day on my way to work in EV mode all the way to the bottom. The heat dwindles all the way down until i reach the bottom. It's never been anything more than a minor annoyance for me because I don't live in an extremely cold climate. Now that I know it shouldn't be doing that, I guess I'll have to consider digging into this little problem! Thanks guys.

 

I'm not sure as I've only driven it a couple times since, but I tried pulling the relay for the cabin heater pump and wiping it off well and putting it back in. It seems to be operating right now. We'll see.