If the CCU is undamaged now, leaving the aux water pump disconnected will not harm the CCU. But as has been said, whatever caused the pump to fail could also have damaged the CCU.

In my case, failure of the pump (during a PO's ownership) caused several traces on the PC board to fry. Someone had done a rather sloppy repair, which I cleaned up. I assume that the pump was replaced at that time but admit I haven't checked it other than measuring the current draw.

Rrgrassi, have you measured the current draw of your pump? It would be interesting to compare my 0.9 Amp to whatever yours draws. A larger initial surge is certainly one reason why mine will eventually blow a 1 Amp fuse but yours does not. Then again, my pump could have been replaced years ago and is again getting old.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970