Wire or Ignition switch?

I have a 4L80E tranny in a 1995 2500HD. I recently swapped all my transmission selenoids due to me getting an error code saying 2/3 shift selenoid wasnt shifting, and, it wasn't. Now, occasionally my speedometer goes crazy, at same time my tachometer drops to zero, and my transmission quits shifting. I had a serviceman tell me it could be a wire from the transmission to the engine, or it could be my ignition switch. Anybody hear of this before, and maybe could offer any insight??

I have a 4L80E tranny in a 1995 2500HD. I recently swapped all my transmission selenoids due to me getting an error code saying 2/3 shift selenoid wasnt shifting, and, it wasn't. Now, occasionally my speedometer goes crazy, at same time my tachometer drops to zero, and my transmission quits shifting. I had a serviceman tell me it could be a wire from the transmission to the engine, or it could be my ignition switch. Anybody hear of this before, and maybe could offer any insight??


This is a pretty common problem. I had this exact thing happen on my 93 K1500 AND on our 91 Lumina Euro. It was the ignition swicth on both. When you take the switch off, you'll see the burn spots through the plastic housing from the arcing that's been going on across the contacts.

This is a pretty common problem. I had this exact thing happen on my 93 K1500 AND on our 91 Lumina Euro. It was the ignition swicth on both. When you take the switch off, you'll see the burn spots through the plastic housing from the arcing that's been going on across the contacts.


Thank You So Much, It has been frustrating too say the least, I don't trust "any" of the repair shops or dealers here. So I try to do all my repairs myself. Thanks

Same thing was happening to my 96, it was the ignition switch. It was burnt to a crisp. Kinda resembled my wife's lasanga or meatloaf! :rofl: