| I decided to try and keep the integrity of the original fuel level sending resistors and was successful. I found that the original resistors can actually be cleaned and brought back to life. They are actually quite durable. The wiper that travels across the resistor can be cleaned to work as well. Also, after cleaning them, I found that the replacement resistor is NOT the exact same value across the scale. It would be close enough to use as a replacement as a last resort, but you would have to use it alone in the main tank and disconnect the connector to the resistor in the sub tank. So please disregard using this resistor as a fix. My loss, live and learn. So here is the good info. How to clean the resistors and wipers. Disassemble the resistor buy unsoldering the wiper and then removing the float arm that the wiper is attached to.
 As you can see in the pictures, the float arm shaft that connects to the resistor is corroded which hampers the movement of the float arm. You will need to clean that as well. The wiper contact is dirty and needs cleaning too.
 
Cleaned. I used a steel wire brush to clean the arm shaft and a scratch pen to clean the resistor and wiper contact. The scratch pen has fiberglass bristles. Use gloves when using it and a paper towel or disposable cloth to clean the debris. Do not get it on your skin. Do not use something to clean it that will remove any of the contact metal. 
When cleaning the resistor, and although much of it looks black, be careful to only clean the scale that the wiper comes into contact with as seen in the pictures.
Before
After
 Also clean this contact.
Before
After
 After cleaning, reassemble.
Both resistors in the main and sub tanks are the same value even though they have a different number on them.
Here is a picture of the 11 test points of interest across the resistor.
Here are pictures of the main tank full, half full and empty values after cleaning.
Here are pictures of the sub tank empty, half and full readings after cleaning.
 
Here are pictures of taking ohm readings after both resistors have been reassembled and connected in parallel as they would be in the fuel tank.
 
Resistor values There are 11 points (PT) of interest across the resistor. Main Tank resistor
PT Ohms
1 - 10
2 - 25
3 - 35
4 - 50
5 - 65 - Half way
6 - 85
7 - 110
8 - 130
9 - 150
10 - 155
11 - 165 Sub Tank
PT Ohms
1 - 10 Ohm
2 - 25 Ohm
3 - 35 Ohm
4 - 50 Ohm
5 - 65 Ohm - Half way
6 - 85 Ohm
7 - 110 Ohm
8 - 130 Ohm
9 - 150 Ohm
10 - 155 Ohm
11 - 165 Ohm The Main and Sub tank resistances are wired in parallel.
These are the values of the points of interest after they have been added in parallel.
PT Ohms
1 - 5 - Full
2 - 12.5
3 - 17.5
4 - 25
5 -32.5 - Half way
6 - 42.85
7 - 55
8 - 65
9 - 75
10 - 77.5
11 - 82.5 - Empty As you can see, the values don't exactly match what you see in the FSM. And the half empty value is what I use during repair of the gauge clusters in all models. When working on a gauge cluster under power the fuel gauge will rise way past full and continue to be under "electrical push" unless you provide a control to it. This is why I always used a 32 ohm resistance across the signal input to ground when working on them so that the gauge will always be set to the half full mark and not add additional electrical strain on the gauge.
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