Check guage alt not reading

[chelan]

05 5.9 new batterys new battery cables since last year all was working fine then yesterday going up a gravel road the guage died, just the alt guage. didnt know what to do so i disconnected and reconnected the batterys then the guage came back to life...but going up that road it did it again. the alt is charging at14.2v confirmed with the smarty and handheld meter any ideas on what wire(s) i should be looking at .

 

[AH64ID]

The ECM isn’t seeing the voltage.

Are both batteries charging at the same voltage?

 

[chelan]

yes charging at the same voltage ,the truck sat for 2 hours after i got home then i started it up and the guage started working again ,so im lost on this problem. the battery connections are tight the grounds to the frame are tight the grounds to the ecm are tight .the cross over cable was replaced a few months ago the batterys are firmly mounted

 

[sag2]

Solder joints on the cluster?

 

[Ozymandias]

If the Temp sensor under the driver's side battery goes bad/out it does exactly that.
Gauge to Zero and standard charging without taking the temperature into.

 

[Ozymandias]

A Scan would show it to you with a Code.