Faulty CD Changer ?

[wrong]

Bought myself a new Mercedes CD Changer B6 782 4025 (one of those newer compact ones with a single slot without the removable cartridge). Tried to install it, but it blows the circuit fuse each time I connect its power loom.
Have spliced CD Power loom (Red/White + Blue/Black) into the back of the MOST/Audio-20CD connector and the Brown is appropriately grounded. There was already a Blue/Black wakeup line present so I just soldered to the existing crimp connector.
Checked the power/lines with a multimeter - everything looks fine, and the Radio etc. still works.

Am I missing something here - or do I have a duff CD changer ? It would be somewhat embarassing to also blow a replacement unit. Bit of an unusual failure - in my experience things generally blow open, rather than short.

Did disconnect the battery whilst making the changes - and did follow WIS retrofit instructions - apart from the Blue/Black cable splicer which MB recommend.

[miro]

I take it that what you are saying is that you took the advice of WIS and got power and also wakeup from the radio .

You put ground where exactly ?

Soldering is very good but the wiring harness is not designed to take the heat. That is why Mercedes suggest you crimp the wires with a double splice lock.

I presume you purchased a W169 CD stacker harness as there are types for other cars such as the W203.

The pre-w169 CD stacker wiring from a W203 does blow things up.

Otherwise I would look to plug the stacker into something else and see what happens.

[wrong]

Having done some electronic circuit design in the past I was rather embarassed to post this question. Nevertheless, Miro, I appreciate your input as I've been pulling my hair out and it's sometimes useful to have someone else looking over your shoulder.
In brief:

> I take it that what you are saying is that you took the advice of WIS and got power and also wakeup from the radio .
Yep.

> You put ground where exactly ?
Chassis ground nut - in passenger footwell.

> Soldering is very good but the wiring harness is not designed to take the heat. That is why Mercedes suggest you crimp the wires with a double splice lock.
Didn't want to cut into the harnass - so I unclipped the live and wakeup lines from the MOST plug and soldered/heatshrinked the new wires to the top of the metal crimp... a splice would have been a lot quicker !

> I presume you purchased a W169 CD stacker harness as there are types for other cars such as the W203.
I will look again at the parts list. All the plugs fitted together...

>The pre-w169 CD stacker wiring from a W203 does blow things up.
This would be rather annoying. Can't seem to find the power pinout for the CD-Stacker anywhere - now that would answer a lot of questions.

> Otherwise I would look to plug the stacker into something else and see what happens.
I've bought a bag of spare fuses just in case :o
Will update after I get a chance to look into it this weekend.

[wrong]

Thanks to some helpful advice, I've now deduced that the CD Changer B6 782 4025 and CD Power Harnass A169 540 2005 are incompatible because the power/earth lines are incorrectly aligned on the plugs. I'd originally ordered a B6 782 4019, but this was replaced by a newer model B6 782 4025 - for some strange reason MB have decided to swap the new CD's power/earth pins. You can figure it out if you know what the the colour of the CD Power lines means, but there are no power/pin markings on the CD-changer, and the changer and harnass can only be connected in 1 way (leading to a short-circuit in my case). A simple swap of the new CD's live/earth leads and everything now works !

The pinout combo that works is as follows:
Switching - Yellow(CD-4025) to Blue/Black(Harnass-2005)
Live - Red(CD-4025) to Red/White(Harnass-2005)
Earth - Black(CD-4025) to Brown(Harnass-2005)