The only AC pump I can think of is the AC compressor, if so it is not technically part of the Hybrid system, but it is used to cool the battery. Does your AC work? $1100 is not that high for a new compressor, fans and all that goes with it. getting a FREE battery pack, priceless!

 

Now that the "quasi-recall" time period is over, if anyone is going to undertake this on their own, it is quite easy and, contrary to the instructions, most definitely does NOT require that the HVTB be removed from the vehicle. My mechanic friend and I did this in about 45 minutes today on my 2006.

The only specialized tool you need is a T-30 tamper resistant TORX socket.

Fortunately the harness is very near the service plug/fuse which is at the very rear of the right side of the front battery cover.

1. First, pull the service plug.

2. You need to remove all of the TORX bolts on both the front (closer to the rear seat) and rear (closer to the rear hatch) battery covers.

3. You also need to remove the black duct piece that channels air from the rear driver window to the battery pack.

4. Tilt the rear seats forward and there are two 10mm bolts holding the front edge of the front battery cover that need to be removed

5. There are two large bolts on the sides of the front cover. We were able to reach those with channel locks.

6. You can then remove the rear battery cover. Careful, the edges are sharp and there is also a large gasket/weatherstripping you don't want to damage. As you start to pull it out, you'll see it has two grounding straps that prevent its complete removal. Just undo the one on the passenger side and you can swing it out of the way.

7. You will then see the target harness...85% exposed.

8. On the end closest to the rear of the vehicle it is covered by a 4" wide piece of foam insulation secured by a tie wrap. Cut the tie wrap, peel off the insulation and unplug the harness. Plug in the new harness connector, re wrap it with the supplied foam and re tie wrap it.

9. The other end has a much thinner foam insulation wrap and no tie wrap.

10. Also, pay attention to the position of the wires and how the harness is tie wrapped to the battery pack as you'll be cutting that one as well.

11. Both pieces of replacement foam and new tie wraps are included in the new harness kit, part number 7M6Z*14A303*B.

12. The hardest part is removing the foam insulation from the front connector. There was at least one bolt (possibly 2) of the sides of the front battery pack cover we couldn't remove. With all the other fasteners removed that I previously mentioned, I was able to pull the rear passenger side corner of the front battery cover up about 1.5" which was enough to allow my buddy enough room to peel off the foam, disconnect the connector, connect the new harness and re-wrap it with the new self-sticking foam.

13. Tie wrap the harness back down as it was before

14. Use compressed air to blow out any foam bits, etc. from the battery assembly.

15. Reassemble. Book time is 2.4 hours and we were easily done in 45 minutes. I took a few pictures that I'll add later.

NOTE: This is how we did it and I offer this to document that only. The battery pack is obviously high voltage and while I will feel bad if you electrocute yourself, your kid and/or your dog, I am not responsible. You are doing this at your own risk being fully advised of the risks in involved.

Connector by my thumb is the harder one to get to, other end is the one with THICK foam and two tie wraps:







The bolts on the sides of the front cover you can grab from the sides with channel locks:

 

This is the old one:

 

The extended warranty is soon to expire as well.

Thanks for the detailed instructions. I followed them and lived to tell the tale. I made two tiny changes and have some tips that I would like to share. I bet with practice this could be a 30 minute job.

It took me a while to figure it out, but this service had been done previously on your vehicle! Your step 7&8 make it clear that when you lifted the lid, you saw a harness in place. You removed the old wire and replaced it with the new wire. The thing is, there should be no old wire! Say you were listing the steps to move a lamp from one end of the couch to the other by adding an extension cord. You say you slid the couch forward and observed an old extension cord already in place. That's not the regular way because you haven't installed the extension cord yet. Someone has been behind your couch before you! At the end, you have a photo of the extension cord you removed from behind the couch. How was it there? Who moved your lamp???

Nobody seems to know what the fix is supposed to be doing. I heard something about a resistor so... maybe one of the wires we're installing is a length of resistor wire. That would be much easier than increasing the value of a surface mounted resistor on a board in a computer somewhere.

3) The strange Philips-head connector on the black duct uses the screw to expand a plastic plug. I had trouble getting it out. Turning the screw did not remove it. Maybe pinching the bottom closed would help the threads grip so it could be screwed out. Maybe a fine blade prying the head upward while the Phillips turns it?
4) I loosened but did not remove the two 10mm bolts on the front edge of the battery. They were behind a foam block that is glued to the floor so they would have been troublesome to replace and the lid doesn't move much there. Seeing how little the lid actually moves, maybe they don't even need to be loosened. I'll try that next time. Probably a third of the forward lid screws just need to be backed out by a centimeter (not removed)

The wording of steps 7) & 8) are for the re-repair. The harness and the zip-tied foam was only in place after the harness was installed. In the regular job, nothing is removed (other than the old thin foam tape).

7. You will then see the target connector...85% hidden. tucked up under the front lid near the service plug. You need to open that connector and install the harness between the two halves. Remove the foam and move the red slide to unlock the connector.

8. The female half of the connector needs to be moved to an empty space. In most vehicles, the connector should be moved to the space near the fan shroud. Sometimes the wire is too short to reach so the connector should be moved to the empty space in the right rear corner instead.
8a. If this job has been done previously, the added harness is now 85% exposed. On the end closest to the rear of the vehicle it is covered by a 4" wide piece of foam insulation secured by a tie wrap. Cut the tie wrap, peel off the insulation and unplug the harness. Plug in the new harness connector, re wrap it with the supplied foam and re tie wrap it.

12) Rather than hold the lid up I propped it up on the plastic handle of my screwdriver.

Disconnecting the original connector is the hardest part, as you say. Removing the old foam tape and separating the connector. Luckily you can practice opening the connector using the new cable. Slide the red bit back to unlock, press in the newly-exposed area. Be sure to slide the lock back in place before re-taping it.

Also, I recommend that you take care when replacing the lid screws. Any grit or dirt must be cleared away keep the battery lid as water-tight as possible.

Anyway, thanks for the help. I'm sure there are a bunch of these problems that we're going to have to fix ourselves if we want to keep these hybrids in service past their 8/10 year expiration date. How many of these cars will escape the scrap pile when the $4000 brakes controller hiccups?

Instructions posted here are a great resource. Maybe my view is twisted because I've been searching on P0A8D, P0A27 and P0A81, but as far as repairs go, they are pretty minor.
????? MECS pump, $130 1/2 hour
P0A8D New 12V battery, $100 1/4 hour
P0A27 Harness $25 3/4 hour (Thanks to your crescent wrench trick)
P0A81 Fan $100(sold in pairs) 1 1/2 hour (?)
Blend door actuator Difficult third screw make a custom tool

I saw a Russian site where they repair the battery fans. They found a blown fuse on a circuit board inside the fan.

I'll come back and update this if I have to do the the fan repair myself. I think it'll take 20 minutes to open and close the rear battery compartment.

 

Interesting. I have nothing that reflects that service ever having been performed on my FEH and I keep everything.

Excellent tips.

 

And something new to add:

Two weeks back our 2006 FEH simply turned itself off, without any prior warning, with the warning chime, red triangle of death and "STOP VEHICLE SAFELY" all going off simultaneously as it shut itself off. Fortunately, it was a quiet evening, and we were on a residential cul-de-sac downhill pointed straight at the driveway and it rolled in and stopped. Turned it off, then tried to restart, but no - all warnings. Leaving it there, a quick little bit of research found TSB 08-15-1, which seemed to make the original Bosch MECS pump (auxiliary electric coolant pump for the hybrid system) the culprit. After a couple of hours it restarted without drama, and we moved it to the garage. The next day I drove it to one of the local Ford dealers, showed them the TSB, and inquired about a fix - out of warranty, of course, and without my request, they ended up running 'diagnostics' for $100 (I did not pay), and not only said the TSB work needed done - $358 for the Ford kit designed for this fix - but another $550 in labor for reprogramming due to the failure. I went to the parts window, ordered the part ($308 5M6Z-8C419-A for the kit or $159 9M6Z-8C419-A for the 'apparent' part alone) - and when it was in two days later I picked it up (after Parts declared the pumps identical, the pump only), and took it to an ASE-certified shop I use for everyday things - and this pump, which looks like an aquarium pump - has an inlet, an outlet, and a single electrical connection. WARNING: These pumps are NOT, in fact, identical! The 'kit' pump - the pump alone, a 9" corrugated plastic sleeve and a plastic pipe clip - is ONLY for the affected 2005-2008 FEH. The $159 pump fits ONLY the 2009-2012 FEH models - the electrical connector is different. The $159 pump did not fit, it was after dealer's hours, and my car was on the lift at the ASE shop - that meant a quick trip to Advance Auto Parts, which had the Dorman 902-001 'kit' they were willing to sell to me for $200 - and that was installed.

One day later, after using the FEH for a regular trip to Mom's house 50 miles away and back, and after sitting idle for a couple of hours, the family loaded up for a trip to the ballpark - and on an uphill expressway entrance ramp - BAM - identical no-warning complete shutdown! We coasted onto the shoulder, called to a relative to pickup the kids and mom, and I waited for AAA. Thinking it must be related to the MECS just installed, I had it taken back to the ASE shop where, the following Monday, they ran diagnostics and found nothing. Now - here's another tidbit - we'd had another Ford dealer recently work on the FEH after we had a dustup with a coyote about a month ago, suffered only bumper damage, plus their determination that the radiator for the hybrid cooling system looked to have been contacted by the pushed-in bumper and should be replaced, even though it showed no leaking at that point. Done in two days. So - thinking on that, I took it to that dealer, this time running on its own again, and made it safely without any shutdown.

Two days later the dealer said it had not been able to duplicate the failure - and they asked to keep it another day. Day 3 - failure! This time they followed the codes back, researched the VIN, and found another TSB 09-18-06, a follow-up to CUSTOMER SATISFACTION PROGRAM 07B48, that almost word-for-word described what had occurred with our FEH. I don't know if it will post well here, but it is easily found through a google search:

TSB 09-18-6 DTC P0A27—INSTRUMENTATION WARNINGS— REDUCED ENGINE POWER
Some 2005-2007 Escape Hybrid vehicles built from 10/13/2003 to 12/19/2006 and Mariner Hybrid vehicles built from 6/10/2005 to 10/11/2006 may have a red triangle illuminated on the cluster accompanied by an audible chime. In addition, the message center will indicate Stop Safely Now and the Powertrain Control Module will command the vehicle to shut down. Diagnostic trouble code P0A27 for Hybrid Battery Power Off Circuit will also be present.

This service procedure replaces Customer Satisfaction Program 07B48, which expired on 8/22/2009. Check the vehicle’s repair history to determine if a 14A303 service harness (7M6Z-14A303-B) has already been installed under 07B48. Do not install a second 14A303 service harness in series with a 14A303 that has been previously installed under the Customer Satisfaction Program.

Install a service harness in the High Voltage Traction Battery (HVTB), and reprogram the Battery Control Module (BCM), to eliminate the circuit that is susceptible to setting a false DTC.

Dealer Coding: Basic Part Number 10B759 Condition Code 42

So - the Ford dealer's service department, based on the codes and the TSB and the CSP, identified the faulty harness as the true culprit, and that this 2006 FEH never had the CSP 07B48 work done - at all. Unfortunately, that part is not readily available anywhere - and our FEH may be idle for up to a week while they search for it, either within Ford's chain, or through the supplier. I've alerted Ford Corporate and tried to enlist their help in this - to me, this is far more than the typical TSB - this is a known, original fault in the harness of a set run of FEH/MMH vehicles that FoMoCo already knew was out there, and that could, on its own and without any prior warning, simply shut the vehicle off completely. While the later TSB makes it appear to be the MECS pump - and ours was the original Bosch, so that might be a separate issue - what appears to be the true, much more compelling issue here is a known failure point in a bad OEM harness that FoMoCo already knows has the ability to completely disable the vehicle.

Thoughts? We purchased our FEH pre-owned in 2012 after an extensive search, and there is no evidence the prior owners ever had notice of the issue. Ours will sit waiting for the part, and then we'll go from there. As of right now, the better half, whose ride this is, does not even want to get behind the wheel again, fixed or not.

 

I responded here.