Hello all,
I'm new to the site and hoping to get some help with a problem. I have searched the threads and have not found my issue.

I have a 2007 suburban ltz and my speedo stopped working around 50 mph. Works great unto there but nothing after. If I'm causing at highway speed (with a gps) sometimes it slowly drops to 45. All other gauges work great. I have checked cleaned or replaced all fuses and or relays, replaced the stepper motor, the speed sensor on the transmission and ever replaced the ECU with a new one that was programmed to my truck. Normally I trouble shoot until I find exactly what's wrong but this is getting frustrating and I could really use some fresh minds on this.
Thanks everyone in advance for the help.

 

I have had a shiny new and superceeded speed sensor in. I thought it had fixed it - I hit 90, then, at that point, bang the needle dropped to 70 and deferred around everywhere. In the wake of fixing different issues on the vehicle (coolant sensor, can transport blunder back entryway) I took the battery out and stripped down the primary earth and the 4 other more modest earth wires. None were terrible, however not incredible, all associations with the wires looked fine. I set them back better compared to new and all around lubed, set up it back and went for a twist. Thought I had broken it, hit 95mph unshakable needle. Then, at that point, returning bang - needle postponing. Presently not so awful as it has been, but rather there is as yet an issue there. The vehicle is a fantasy to drive and this is the main functional issue, I have put such a lot of work in during the last year developing it this last shortcoming is drivig me insane. Has anybody any ideas? I have VCDS so I can do any test or log. Yield trial of the instruments is great, full needle avoidance. Showing the speed on the climatronic made the speedo needle delayed to react and the speed mistaken/too sluggish and simply no sense so that didn't help. Tutuapp 9Apps Showbox