Fuel gauge issue

[jlawles2]

I am getting low fuel light gauge on empty.

Just had the cab off for a bent rod and now I have no fuel level and the temp gauge on the rear view mirror shows "OC".

Anyone have any ideas? Checked fuses and all are good. I did have a couple of grounds not hooked up, but have found them and hooked them up.

Anyone have any ideas where to start?

 

[jlawles2]

Any Ideas?

Could it be the BCM?

 

[MACKIN]

Just to say double check all your connections and grounds

 

[TLyons90]

X2 on checking all your connections to make sure they were replaced properly or maybe leaving just 1 of as well as your grounds... Also is it throwing any codes?

 

[jlawles2]

No codes. I did find the outside temp on mirror issue. Also air bag was saying needs service. Fixed both of those with one connector. Connector for mirror temp is a four wire in single row connector under the fuse block outer cover.

Before I had the cab off, the batteries ran down (since replaced) and the fuel gauge was slow to come back up. Today I checked the resistance at the tank (58 ohm) and followed the lines back up and under the fuse block. Pulled the same resistance there (58 ohm). Need to verify that if I unplug the sending unit at the tank i get no resistance. Also need to check voltage at the plug to see that it is getting the correct amount.

From the way I read the diagrams (need some help with this one), the ECM receives the fuel level from the tank sending unit and relays it through the 2 serial data bus back to he bcm where the bcm then sends the signal to the fuel gauge.

I did have the instrument cluster rebuilt about a year ago. Is it possible for the instrument cluster to have an issue which will cause both the low fuel light and an empty reading?

 

[jlawles2]

Finally found the issue with the fuel gauge. Plug under fuse block had bent pin. However the connector was locking and was tight.

Apparently the connector does not need to go face to face to lock.

 

[TLyons90]

Glad you figured it out bud! :thumb: