Aux. Water Pump takes out CCU - Page 4 - PeachParts Mercedes-Benz Forum

Jeremy5848 · #46 02-02-2007, 04:28 PM

Quote:

Originally Posted by cbjukraine

what else can damage the CCU? with the aux pump completely removed from the car, do I need to worry about the CCU being damaged because the aux pump isn't there to draw current as it normally would?

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.

rrgrassi · #47 02-02-2007, 04:32 PM

Quote:

Originally Posted by Jeremy5848

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.

Jeremy, actually, I have not done that yet. Now I'm curious...I'll try to do that this weekend and post the finding.

rrgrassi · #48 02-02-2007, 07:25 PM

Jeremy, I tested it when I got home from work. I also started a new thread with this info.

Mine varied between .3 and .5 amps. Initial starting draw at engine operating temp was .7

I hope this helps!

Jeremy5848 · #49 02-02-2007, 08:20 PM

OK, then my 0.9 Amps is too high, suggesting that my pump is starting to fail, probably due to years of crud building up on the pump pieces. I wonder if the pump can be disassembled and cleaned? I have the time and it would be nice to save a few bucks (if cleaning would help). At any rate, it explains why you can use a 1 Amp fuse and I have to go to 2 Amps.

It also tells all of us that, if we install a new pump or are able to operate our old pump as you do, on a 1 Amp fuse, that when the fuse starts to blow from time to time and changing the fuse doesn't help, that it's time to do something about the pump.

I'll post to your new thread. It will be nice to get an idea of the current range different pumps draw.

Jeremy

**** DANGER ****
10,000 Ohms
***************

whunter · #50 02-02-2007, 08:47 PM

Quote:

Originally Posted by Jeremy5848

I wonder if the pump can be disassembled and cleaned? I have the time and it would be nice to save a few bucks (if cleaning would help).

Fixed Auxiliary Water Pump!!
Fixed Auxiliary Water Pump!!

Jeremy5848 · #51 02-02-2007, 08:52 PM

Quote:

Originally Posted by whunter

Fixed Auxiliary Water Pump!!
Fixed Auxiliary Water Pump!!

Thanks, a nicely illustrated DIY. I remember seeing it last year when I was adding my fuse. What about the pump half? Did it look to you like it would also come apart?

whunter · #52 02-02-2007, 11:07 PM

Quote:

Originally Posted by Jeremy5848

What about the pump half? Did it look to you like it would also come apart?

I rebuilt my Auxillary water pump
http://www.peachparts.com/shopforum/general-information/38739-i-rebuilt-my-auxiliary-water-pump.html#post219859

Jeremy5848 · #53 02-03-2007, 12:10 AM

Quote:

Originally Posted by whunter

I rebuilt my Auxillary water pump
http://www.peachparts.com/shopforum/showthread.php?p=219859

Thank you, that was what I was looking for.

speedy300Dturbo · #54 02-06-2007, 03:14 AM

Here's a fried W126 pushbutton unit, thanks to an auxiliary water pump that drew too much current!

Jeremy5848 · #55 02-06-2007, 12:17 PM

Quote:

Originally Posted by speedy300Dturbo

Here's a fried W126 pushbutton unit, thanks to an auxiliary water pump that drew too much current!

Similar to my 123, fried in different places but it's clear that the same thing happened. With care, it's possible to wire around the fried traces. Thanks for posting the pictures.

#56 11-02-2010, 08:27 AM

It's pretty easy to set up and measure the current draw on the aux pump. On the 124 car it should not draw more than 1.3 Amps. I expect that 1.3 Amps would be a good upper limit for the 123 pump as well.

whunter · #57 08-18-2013, 07:48 PM

for new members

Mark DiSilvestro · #58 08-19-2013, 08:38 AM

A few years ago, there was a sad thread here titled 'I Lost it All' about a burnt W123 300D. The OP said his dash started smoking above the climate controls and caught fire while he was driving. He managed to get off the road in time to watch his car go up in flames!
An overheated CCU was the suspect. Carrying a fire extinguisher and adding a fuse to the pump circuit was strongly advised.
I have seen a few of these CCU units in salvage-yards where it's plastic case was actually melted or starting to burn.
Another reason I chose a 240D and Euro 300TD, and avoided any of the ACC equipped models.

Happy Motoring, Mark