Welcome to the SeeMeCNC Community

I'm running a Max v2, and I have that nagging problem with the EZStruder stepper motor getting warm enough to make PLA squish up next to the hobbed gear. So I'm going to install a 40mm cooling fan (and likely a heat sink) on the EZStruder motor as several people have suggested.

I'd rather not have to use a separate power supply for this cooling fan, and I'd rather not have to disassemble the whole printer to run another wire pair through one of the tower supports.

Is it OK to wire this new cooling fan in series with the PEEK fan? RAMBO can handle double the current on that fan circuit?

It should be no problem. I added two more fans to my layer fan circuit. Make sure you wire it in parallel, though.

I wouldn't. Because two 12vDC fans in series will get 6vDC each. Assuming they are exactly the same.
Connect them in parallel.

You beat me Mac

Gack. What was I thinking? Parallel it is!

Also, look into this. I had the same issue you're describing, and changing the stepper motor current fixed it.

http://forum.seemecnc.com/viewtopic.php ... er+current