Diagnosing dual tank balance module

[MrMarty51]

I was replying to the above
THEFERMANATOR
post about what controls the secondary pump since that was the discussion. Sorry

Not a problem. I was only suggesting starting a new thread as this one was last posted to in 2019.
A new thread with a new member signed up always gets a lot more attention than an old thread.
Didnt mean any harm in any way.

 

[Will L.]

Use it like this to send a note to him

@THEFERMANATOR

 

[THEFERMANATOR]

Does the PCM also control the secondary pump in a 2003 8.1L Gas C4500? I can't find the module

Yes, it is a completely different system than the balance module system. Both tank level units go to the PCM, it converts each tanks reading into 1 total reading and sends that signal out to the fuel gauge, it also controls the transfer pump operation.

 

[TN454k3500]

I know this is an old thread, but has been super helpful. I have a 1997 K3500 7.4L dually, only has 64k original miles

The fuel gauge/transfer tank has been an issue. The first post by Matt was exactly what I needed.

I've done all the checks, but when the balance module turns the transfer tank pump on the fuse blows (when I ground out the solenoid to turn the pump on....). If I remove the transfer pump out of the circuit and put my volt meeting on the plug I get a constant 12.5-13V. This tells me something with the transfer pump is bad, is this correct?

Front tank level reads ~96 ohms when full
Rear tank level reads ~125 ohms when full - Hasn't been emptied in a while.....

 

[MrMarty51]

If the fuse fails to burn out with the pump disconnected then, be My guess, there is a shorted feed wire between the connector and the pump or, the pump motor is shorted internally.

 

[JJR]

You can just hook the sending unit directly to the dash gauge, I did that and it works just fine, although the dealership said it wouldn't. I used a two position toggle to choose which tank to read from and put my transfer module on a toggle as well, way cheaper than a new balance module, and it works better too.

Can you tell me what wires you hooked to each switch? My truck just quit and the garage replaced the fuel pump (needlessly) and $1000 dollars later they hotwired the fwd pump to the taillights and I cant get it to work correctly with all new parts and troubleshooting. [email protected]