[W126 Coupe] Looking for a short in the A/C circuit.

[Dick Spellman]

Dan,

Give it a tug on the front edge just slightly downward and then pull 
towards you.  You got at all the fasteners.  You may find that the 
carpet in the footwell to the A-pillar will hang it up a bit but, it 
should come free without having to disturb that right side carpet panel.

Dick

Dan Stratton wrote:

> Still dealing with this problem, I've disconnected the monovalve, aux 

> waterpump, AC compressor (still blows the fuse.) I haven't figured out 

> how to remove the passenger knee bolster to get to stuff under the 

> dash. I've removed 3 screws on the upper edge, 1 screw lower center 

> and 1 plastic screw on the console but the bolster still feels like it 

> is attached.

>

> Thanks for everybody's help (and especially Dick Spellman).

>

>

>

>> Hi Dan,

>>

>> You are on the right path to eliminating whichever component has

>> developed a short.

>>

>> I see 5 components that share that fuse 5 circuit. Monovalve, aux water

>> pump, aspirator blower, vac. switchover valve, acc pbb control unit in

>> the wiring schematic.

>>

>> Disconnect monovalve (sounds like you have done this)

>> Disconnect auxiliary water pump (this shares the same cable loom (in

>> series) as the monovalve and is below the monovalve assembly

>> Disconnect he aspirator blower (this requires you remove the passenger

>> knee bolster and reach up onto the shelf (careful sharp metal lip) just

>> to the right of the glove box door, locate the holder and the small

>> motor with blower (basically a small barrel on its side), wire leads are

>> very small gauge (careful not to break) and unplug the 2-wire connector

>> from blower.  If you remove the assembly careful on disconnecting the

>> hose that goes up the a pillar to the courtesy lamp air grill.

>> this leaves the acc pushbutton unit it self

>> Disconnect vacuum switch-over valve...with passenger knee bolster

>> removed you can probably see and reach the vacuum switchover valve that

>> sits to the right (vertically mounted next to the acc pushbutton

>> control) if it's not visible with knee bolster down, remove the side

>> carpet panel on the passenger side of center console (remove the one

>> screw in foot well that secures carpet on its face, pull carpet from

>> floor area forward then release the plastic tabs pulling downward until

>> carpet panel is free) disconnect two electrical leads to vacuum

>> switchover valve))

>>

>> If after these 4 are disconnected (leave acc control in) the fuse holds,

>> you know the acc control is okay and the individual wire harnesses

>> feeding each component are okay.  If it still blows, the control is the

>> likely culprit or it could be a dead short on any of the wire looms. If

>> you find it still blows, disconnect the acc control (I am not going to

>> write this up here, it's in the archives) and go though each of the

>> harness testing for high resistance and shorts to ground.  I'd then

>> meter each of the devices for heavy resistance or just plug one

>> component back in at a time until you blow a fuse if the harnesses are

>> okay..

>>

>> Let me know what you find. hey, there may be a faster way to

>> troubleshooting this, but, that's how I'd go about it given my limited

>> non-mechanical experience.

>>

>> Regards,

>> Dick

>>

>>

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