I bought one of these off ebay for $15 (came with a USB programmer too, but I was only really after the clip):
Here's a brand new EEPROM I've clipped in, to have a look how it connects:
Seems to work well enough...
Tried it out tonight, the V850E chip's manual states that if you are in reset mode (see the picture below for where I connected the wire to the capacitor to reset the chip when I wanted - you should be able to hold it in reset mode as long as is needed) OR you are in flash programming mode, where most pins stay in their reset (tri-state) configuration...
Then you can connect up an Arduino Nano using pins A4 & A5 (SDA & SCL respectively) to the EEPROM pins (using a common ground, and +12v applied to the Cluster's black-socket power pin) and read/write it while it's still soldered to the circuit board. That youtube video showed some specialist equipment that supplies ~3.0v to the board so the V850E chip doesn't quite power up properly, but still lets you talk to the EEPROM. No-one should attempt that with the cheap stuff being used here, you're likely to corrupt the EEPROM or ruin some of the other components.
This has been a community safety announcement
I forgot to mention, viewing from the front of the Cluster circuit board, the EEPROM is actually upside down - best not to mess with it if that comes as a surprise though.