Many Thanks to Rick Aiello for helping sort this Steel's correct wiring out.
It saved having to break down 3 or more Valcos to determine & ensure correct factory wiring.
------- oOo -------

Tech Schematic for the CORRECT wiring of this El Grande is provided below.
NOTICE:  This steel's wiring had probably been redone a number of times in it's long past, and so it's wires color codes are "surely" NOT CORRECT.  Except for reinforcing old wire splices with heat-shrink, and reinforcing the bobbin's coil wires to pickup leads solder points with Franklin's white glue, ....I did not want to disturb / re-do the pickup lead wires due to the extreme delicateness of the coil wires / pickup leads solder points junctions on the bobbin;  So I left the previously existing wires & color coding intact.

The coils / bobbins are turned 180 degrees from each other on the pickup mounting so that their wires will face towards each other for better coil mounting and wire routing purposes.
See NEXT PAGE;  Disassembly, Repair and Reassembly of the Pickup Assembly.  >>>
1953 Valco El Grande Steel Guitar
Customer's Work Progress Reports

~ Page 17;  More repair of the electronics ~

This Page Under Construction
HOW A POT FUNCTIONS:  A pot has an almost completely
round resistive race inside upon which a conductive brush-wiper
turns upon that race.  The resistance of the entire length of the
race is the resistance rating of the pot.  The wiper is always
connected to the center lug / tab solder point;  The lugs on
either side of the center lug are connected to each end of the
resistive race, and each lug will have the resistance between
the lug and the center lug / wiper.  So in the example diagram to
the right here, let's say the pot's / resistive race value is 500K
ohms, and let's say the wiper is at 25% distance & resistance
from lug #1 and 75% from lug #2.  The resistance between the
center lug / wiper and lug #1 would be .25 x 500 = 125K ohms; 
While the resistance between #2 and the wiper would be 375K
ohms.  When you view a schematic of a pot either from the top or
the bottom of the pot, it is easy to envision how the pot works in
the circuit by having a mental image of this diagram relative to which way the knob turns looking down upon the top of the pot OR upon the bottom of the pot.  If we were looking at this pot from the top then the knob would be 25% up;  And if we were looking at it from the bottom the knob would be 75% up.
Wiring Diagram / Layman's Schematic
See NEXT PAGE;  Disassembly, Repair and Reassembly of the Pickup Assembly.  >>>
RESULTS OF PLAYING / TESTING THIS STEEL:

My rewiring of the pickup coil was to correct a bad connection I searched for because one of the two coils were found to be weak when previously playing the Steel;  Although I also suspected that the weakness was due to this model Valco Steel having only 1 pickup magnet instead of 2 like most other models.

But upon playing & testing the Steel, the same pickup coil was still weak even with a second original magnet installed in the pickup.

So I did some networking to find an original schematic for the Steel's wiring;  Which showed that the Steel is not wired like it was from the factory;  It's pickups were wired in parallel rather than factory series.  But wired in parallel should have worked although more electronically / tone dynamic in response, and very slightly weaker in output for both coils equally.  More testing would have to be done to find out why one coil was weaker than the other, particularly at one string pole of the weaker coil (which is symptomatic of a short in the weak coil that was eventually found, as shown in subsequent pages here).

I will also do some more advanced tests of the electronics, and of the magnets to see if they need a stronger recharge.

If the coil is bad I will replace it with a good original coil.

All of this will require re-disassembly, troubleshooting, fixing and reassembly of the electronics assembly.  But this time it will go much faster than the previous disassembly and repairs, because I have already recently been through this Steel's electronics assembly and now won't have to go so meticulously slow studying, making notes and documenting for reassembly.  I will start the disassembly Monday evening 12-1-08.

Shown below is the CORRECT wiring in both a tech schematic and a layman wiring diagram schematic, along with some info about same:

------- oOo -------

This El Grande was miswired in it's past;  Apparantly by a hobbyist trying to get a humbucking configuration from the pickup coils; But it could be just a bad wiring job.  In any event, I will rewire it to the schematic below that is correct.

I will add additional text and pictures as the disassembly, testing and rewiring progresses.

------- oOo -------
The coils / bobbins are turned 180 degrees from each other on the pickup mounting so that their wires will face towards each other for better coil mounting and wire routing purposes.
OUTPUT
JACK
HOT
GROUND
------- oOo -------

Tech Schematic for the CORRECT wiring of this El Grande is provided below.
NOTICE:  This steel's wiring had probably been redone a number of times in it's long past, and so it's wires color codes are "surely" NOT CORRECT.  Except for reinforcing old wire splices with heat-shrink, and reinforcing the bobbin's coil wires to pickup leads solder points with Franklin's white glue, ....I did not want to disturb / re-do the pickup lead wires due to the extreme delicateness of the coil wires / pickup leads solder points junctions on the bobbin;  So I left the previously existing wires & color coding intact.

Many Thanks to Rick Aiello for helping sort this Steel's correct wiring out.
It saved having to break down 3 or more Valcos to determine & ensure correct factory wiring.
Yellow
Orange
Purple
below.