Aftermarket Gas Gauge signal connections; purple, orange/black wires?

[Jim Burray]

hello and thanks for accepting my new profile to your GMC forums. I have a 1999 GMC sierra 1500 extended cab 4.8 engine and i have been maintaining / updating parts since of the last two weeks. im trying to fix all the small issues that i couldn't fix during the winter. My fuel pump wiring colors are : grey, black, orange with black line and purple

Right now im trying to do a simple quick fix to an old problem that i have. My gas gauge recently gave up and now its reading zero/empty even though the tank is full. instead of going the stepper motor route i decided on getting an aftermarket gauge as a temporary fix.

My main question would be: how would you go about in wiring this aftermarket gas gauge up? i already hooked everything the way it should; black wire to battery ground/ red is a 12v ignition key source which i found a yellow wire (probably power seats) tucked under the door's plastic floor panel.

I jumped the purple wire and connected it to my signal terminal on the gas gauge but it doesnt do anything. when i touch the signal terminal with test light with ground attached to it; the level then move all the way to the full mark (almost full). I only used the purple wire coming from the fuel pump; do i need to connect any other wire from the pump to the new gauge?

I bought the 240ohms (full) to 33ohms (empty) gauge from amazon - link below

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i feel stupid asking this but i honestly dont have a clue; maybe i had to connect the ground from the pump onto the ground on the gas gauge? Im not sure

 

[Jim Burray]

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[Jim Burray]

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[AK49BWL]

Jumping the fuel sender wire directly to the gauge wouldn't give you an accurate reading of capacity, as that info is sent to the cluster over Class2 Serial from the PCM in the GMT800 trucks if I remember right. Have you checked the sender with a multimeter to be certain the sender is still good and reading in range? With the PCM in control of the gauge, all faults with the fuel sender (open circuit, short to ground) will result in an empty reading on the gauge.

 

[GoToGuy]

Guess work, plus fuel , can equal a very bad day.

 

[Jim Burray]

Jumping the fuel sender wire directly to the gauge wouldn't give you an accurate reading of capacity, as that info is sent to the cluster over Class2 Serial from the PCM in the GMT800 trucks if I remember right. Have you checked the sender with a multimeter to be certain the sender is still good and reading in range? With the PCM in control of the gauge, all faults with the fuel sender (open circuit, short to ground) will result in an empty reading on the gauge.

Im not the best at describing but ill try...

at first the gauge was working normal then one day i shut the car off for a minute and then turned the key to the ON position and the needle on the gas gauge ping all the way to full. It does a slow sweep towards the full. I forgot if the needle sweep has gotten faster after trying the key over and over. anyways after trying for so long, my gas gauge stop sweeping all together and stayed stuck on empty.

I though i read that you could hook up a aftermarket gauge. the purple wire was suppose to be signal and the orange / black was return? , grey is power to fuel pump and black is ground to fuel pump. some guys have aftermarket gauges in their clusters and even extra gauges just because they dont trust their factory gauges,

I have my own ground direct from gauge to battery, i wonder if i had to connect the ground from the pump to actually get a reading ...

This is a temporary fix for me and i will repair it with the correct stepper motors