[W126 Coupe] Strange electrical behavior questions

[Dick Spellman]

Hi Josh,

Well you have the early set-up on the fuse in the fuse box for the climate
control blower.  This must be removed along with the circuit and placed on
the firewall in a special kit available from MB dealer direct.  Less than
$15 and uses a flat foil 30amp fuse.  The fuse if left in the box will
ignite the wiring harness underneath which is how MB came to offer the
upgraded kit I just described.

The story goes that the negative and hot for the outside temperature gauge
run directly under the hot acc fuse in the box. (dont ask me how I know
this!) The fuse holder gets so hot it melts the tray plastic and lowers the
holder until it comes in contact with the temp harness.  Then your wires
smoke up and fuse together clear up to the back side of the instrument
cluster.  If after replacing the original fuse with the correct foil fuse
and holder you still blow fuses, then it's probably time for a new acc cabin
blower located up under the passenger knee bolster.  You need to disconnect
battery and open the fuse box tray to see what's going on under there the
fuse tray first!

The rest Bellamy has covered and it seems you already know the signal
selector and high beam stem and mechanics need replacing.  One comment on
the steering wheel bolt.  Warm body holds the wheel at 10 and 4 firmly.  You
open door place a 3 foot breaker bar on the socket and make a swift ccw push
not a slow burn. Almost a whack on the bar and it'll come free without
messing your warm bodies hands up or the lock on the steering wheel.

I'd pull the instrument cluster to see if you have had a previous fired wire
escapade as described above that may have damaged the leads to the grounding
blocks.  That would cause other things to not function well or
intermittently.

Regards,
Dick



On Fri, Aug 22, 2008 at 3:40 PM, Josh Allen <heyallen at null-ptr.net> wrote:


> Markus and Mr. McGoo,

>

> I'll take a look at the push button unit, I have two (or even three, if I

> consider the one in my other car) nearby to play with.

>

> As far as the fuses go, it appears that the only reason I melted the one

> fuse body was due to it being an exceptionally poorly formed conductor on

> the BUSS fuse I purchased from Schucks. Before I replaced the fuses just

> because, I had had no problems.  The new, junk, fuses metal bits were not

> formed evenly, and looked more like they were folded over the ends, with a

> small attempt at putting a dimple in them, rather than the conical end that

> the old fuses had, and that the new ones have as well.

> No problem there, as I replaced it with one of the older fuses, and then

> ordered a set of ceramic and copper GBC fuses off of one of the vendors who

> stock them. Once I had removed the Schucks fuse (with the partially melted

> body), I got the fan function back, until this latest odd behavior started.

>  While it was melted, I had no fan at all.

>

> Regarding the high beams, I've checked the bulbs, and the wiring from the

> fuse box forward, by jumpering from the low beam power to the high beam

> power.  The high beams lit, they just won't when selected internally.

>

> On the rear window defroster, mine flashes bright,  but doesn't stay on, so

> I suppose I'll have to see what else is wrong with that system.  Somewhere

> along the line, at least!

>

> Thanks for the suggestions all,

> -Josh

>

> Markus Meyer wrote:

>

>> Josh,

>>  As these cars get older the solder joints in the pushbutton unit can

>> cause strange issues, assuming all else is well.  Might be worth swapping

>> out with a known good one to test that theory.

>>  The euro wipers/sprayers on the lights are supposed to work with the

>> lights on, windshield wipers working.

>>  You mentioned replacing the fuse once, then again and found it "melted".

>>  That would be worth keeping an eye on.  First thing I'd do is change ALL

>> fuses to the newer ones as they are old by now if original and can often

>> cure electrical gremlins.  Cheap to do even if it doesn't change a thing

>> (about $10 for all fuses).

>>  Markus Meyer

>> mfm at meyerprobateproperties.com <mailto:mfm at meyerprobateproperties.com>

>> www.meyerprobateproperties.com <http://www.meyerprobateproperties.com>

>> Meyer Probate & Properties, LLC

>>

>> 484-919-9762

>>

>>    -------- Original Message --------

>>    Subject: Re: [W126 Coupe] Strange electrical behavior questions

>>    From: Josh Allen <heyallen at null-ptr.net>

>>    Date: Fri, August 22, 2008 4:14 am

>>    To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>

>>

>>    Josh Allen wrote:

>>    >

>>    > 4th:

>>    > How is the defroster supposed to work? I can select it, and it

>>    > momentarily gets brighter on the upper position, but nothing

>>    seems to

>>    > say that it's working, and it doesn't seem to defrost anything.

>>    >

>>    Err, I mean to ask about the rear window defroster. The front one I'm

>>    fairly sure I understand. (It just wants to play with my hed

>>    currently. :)

>>

>>    -Josh

>>    The MB Coupes Website!

>>    W126 SEC Mailing List

>>    Postings remain property of MB Coupes, L.L.C.

>>

>> ------------------------------------------------------------------------

>>

>> The MB Coupes Website!

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>

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