i recently purchased a 2001 GMC Yukon XL 2500. Had to replace the battery and front fuel pump promptly. Now the dash lights have been flicking on and off along with the speedo malfunctioning as well. I have also noticed when I use the blinker the battery gauge is affected more then it should be. Is this an alternator issue or something more? Any ideas?

Thanks in advance.

 

grounding issue prob. check your battery cables

 

Thank you for the reply. The battery has a clean right connection. The gas gauge starting doing it as well. Any other suggestions?

 

Like Irish said, you need to check the grounding. That means you might need to pull apart the dash, find the wiring harness, and trace the ground wire to where it screwed to the metal body. It could be a loose screw, corrosion or broken wire.

If you want some clues where to look, grab your wiring diagrams ...
BBB Industries- Premium Alternators, Starters, Power Steering Products and Turbochargers | TSB and Wiring Diagrams Database
... and harness routing diagrams ...
https://www.gmupfitter.com/pages/body-builder-manuals

Good luck.

 

Thank you. Will try

 

Check your ground that is directly underneath the driver seat. I had a dash issue and cleaned that ground, cleaned the frame with a wire brush, and used brake Kleen to clean the spot. Havent had any more issues with it. (Although my issue was a 'service brake system' issue I think.