Aftermarket Fuel Tank Selector Valve Installation & Pinout

Since it's not readily possible to get a new plug and play fuel tank selector valve (FSV) for older Ford trucks/vans with dual fuel tanks, new valve kits must be purchased and the wiring harness/pigtail needs to be changed. It will also come with a new specially crossover rocker switch, but you won't need to use it since the stock switch works the same way. Just toss it in your spare parts box in case your factory switch breaks for some reason.

There is very little good info about this online, so I decided to document the installation info from my 1985 Ford E-350 6.9L IDI diesel RV. 

The info contained in this article applies to this style of valve, for both diesel and gasoline applications. Wire colors may vary between years and fuel types, but the connections are probably always the same.

Replacement valves have the hose connections reversed, so it will have to be mounted upside down for the 4 outlet connections to face properly. This means drilling two new holes in the frame for the 5/16" bolts (not included with the kits).

It appears that all valves on the market are manufactured by Pollak/Standard Motor Products because the AutoZone/Duralast FSV2K kit came with an instruction sheet with a document number (GF5642-4REV ALT. B) that matches the installation instructions on SMP's website: https://eaccess.smpcorp.com/eCatalogs/Downloads/EMD/GF5642-4REV.pdf

Here is the original pigtail I cut off. Ignore the clip-on taps, I used them to force the fuel gauge to read one tank or the other, prior to replacing the FSV.

The pinout for the factory connector and valve is as follows. The pinout should be the same regardless of wire colors, but do your own research if in doubt: 

The stock harness is numbered that way, 1-5, while the aftermarket harness is lettered A-E (F is unused)

So, the way my vehicle needs the new harness wired in is like this:

Number 1 (brown, switch) to Letter D
Number 2 (red, switch) to Letter E
Number 3 (light green, front sender) to Letter A
Number 4 (yellow, fuel gauge) to Letter B
Number 5 (dark green, rear sender) to Letter C

Going off topic for a moment: If you have the "newer" style of valve with the clip connectors for the fuel lines instead of hose+clamps, and you need the schematic/pinout for that, here you go. It appears to be the same pinout as the older hose+clamp style FSV.

Back on topic now: Be sure to buy and install in-line fuel filters between your tanks and the valve, since warranty requires it. Plus it should help avoid problems with the valve being damaged/clogged by particles from your tanks, so you maybe won't have to mess with a warranty claim at all:

Since I bought my kit from AutoZone with a lifetime warranty, I wanted it filtered. I bought a pair of AutoZone's FF3330DL fuel filters, which are $3.99 each, as of the date of writing this article. They have 5/16" hose barbs, while the fuel line is 3/8", but mine aren't leaking since it's "close enough" and the hose clamps seal it up. 

I wanted something more rugged than plastic, and I find the cheap cleanable glass ones being made today with metal caps on the end (such as this) tend to leak from the rubber gaskets at each end. You can't go crazy tightening them or you risk breaking the glass. 

Here is the finished product of my new FSV installation. Due to my Holley Red lift pump having to occupy the space (mechanical lift pump deleted), it makes the space for the FSV very limited, since that entire space was originally dedicated to the FSV alone.