Fuel gauge not working

[D10Blazer]

Hey guys so I have an m1009 with the 6.2 a couple days ago I pulled the dash to replace all of the dash bulbs (the fuel gauge was working ) that were burnt out. After removing everything to get the dash panel out I had noticed it was covered in dirt and grim so i decided to clean with with electronic parts cleaner. After I cleaned the plastic sheet on the back of the dash I placed everything back in and fired up the truck only to notice the fuel gauge plummet to way below empty and then sit there. What should I do I am pretty mechanically inclined i just have no idea were to start any info or guidance is appreciated.

 

[Takai13]

Are you sure that everything got reconnected and a lead isn't loose? Sounds like you have no positive. Bad ground would peg the gauge.

 

[Mainsail]

The TM has a great troubleshooting procedure.

 

[D10Blazer]

All of the leads are connected I checked the left lead for voltage and got a reading ,when I checked the right I got nothing when all 3 leads touch the gauge falls below empty all the way to the 9 o clock position when I disconnect the right lead the gauge stays at 3/4 tank. I would use the TM however someone hacked out the 24 volt system there are cut and chopped wires everywhere. When I pulled the dash the gauge worked after I cleaned all leads on the back of the dash panel and plugged all bulbs in the gauge failed