1999 Tahoe Fuel gauge always reading full?

[Oleg]

The fuel gauge in our 1999 2 door tahoe is pegged on full. I changed the fuel pump and sending unit about 2 years ago with a racetronix module and has been working fine until recently. At first the gauge would bounce around between empty and full but now it is just pegged at full all the time. Any ideas what it could be?
Thanks

 

[Oleg]

Cleaned up the ground on the frame and it didnt seem to help.

 

[JollyGreen]

If it isn't the ground it can only be one of two things:

1: sending unit
2. cluster

 

[TruckinAin4Sissies]

It's the gauge coil, without a doubt.

Options:
* Buy (used) cluster and swap the odometer

* Have the cluster serviced.

I've done many.

-Truckin-

 

[Oleg]

Any idea if a 95 cluster is the same as a 99? I went to the local pick n pull and the only one left was a 95.

 

[JollyGreen]

It should be the same. I don't think that changed from 95 on.

 

[Oleg]

Tried the 95 cluster and it did the same thing. I'm guessing next is the sending unit? Do the 2 purple wires go to the PCM so i could test them with an ohm meter? Ive been looking at diagrams but only see one wire instead of two at the pcm for fuel level.

 

[bluex]

You need a 98+ cluster. The fuel level started going through the pcm in 98 so an older cluster isn't going to work probably. 95 is a one year only cluster as well....

 

[454ss]

they had problems with corrosion build up on the senders starting in 99 nbs i know. gm had an additive to clean the sender slide and stuff. im pretty sure the obs 99s got this same new sender/pump unit where its all replaced together unlike pre-99.

 

[JollyGreen]

You need a 98+ cluster. The fuel level started going through the pcm in 98 so an older cluster isn't going to work probably. 95 is a one year only cluster as well....

Really? Hell, I thought the cluster was the same. I did forget about the level going through the pcm.