My daughter had the same problem with her 2012 Fusion Hybrid..."High Motor Temperature" warning and chime would appear and disappear so fast it could barely be read. Thanks to this forum I was able to fix the problem. Thanks, jfutter for the info about the temperature sensor and wiring assembly. And thanks, bboyd for confirming. Here's a little more detail about what I found. First, I called the Ford Dealer with the VIN to check availability of the parts that jfutter listed. It took a little while for them to find the temp sender (or sensor) that is for the electric motor cooling (not the engine temperature sender.) The dealer asked if this temp sender was located in the bottom of the transaxle. I said I didn't know because I hadn't looked at it yet, and have never worked on a hybrid. Then I gave them the part numbers that jfutter listed and those were it..temperature sending unit 3F1Z-12A648-A at the bottom of the transaxle. The wiring assy 3U2Z-14S411-HYB would take them a day or two to get, so I decided to start with the sensor and go from there. I removed the lower engine splash shield, and the smaller shield in front of it. The sending unit was easy to locate in the bottom of the transaxle. The first thing I noticed was the wire going to to sending unit was extremely tight and causing extreme tension on the sending unit (probably a factory installation defect). After removing the connector to the temp sender, I removed a couple of the strap fasteners on the wiring harness that the sender pair of wires go into (about 6 inches away) and cut the harness open to get at the wires. One of the wires had a noticeable bend in it from the extreme tension on the wire. I used a multimeter probe and poked through the insulation of the suspected wire and checked continuity from this point to the sender connector and found NO CONTINUITY. But if I moved it some it would make a connection. Then I carefully cut the wire insulation off the wire with the noticeable bend (wire color might have been the purple with a green or brown stripe, can't remember for sure) and found broken copper wire inside. There was so much tension on that wire that it broke the copper strands inside the wire insulation, and movement would cause the strands to make and break connection. The other wire going to the sender was ok. I cut the wire at the bad place and added a couple of inches of wire inbetween to take the strain off the wire, crimped with connectors, taped all back with electrical tape, including the harness, refilled coolant reservoir. Problem solved, no more warning or chimes. I wouldn't have had to buy the sending unit to fix it. Parts 3F1Z-12A648-A Sender Asy $21.60 Motorcraft Special Orange Coolant 1 gal premixed $13.36
