[Murphy Clyde]

What does the Gear selector switch circuit consist of on the 1993 GMC Sonoma??

 

[RayVoy]

A code 72 is a speed sensor code.

It's in the transmission tail piece (2wd), in the transfer case output shaft area (4wd).

Check the wiring firrst

 

[Murphy Clyde]

Thanks Ray ~ Could this cause the Automatic transmission from going into drive and overdrive??

 

[RayVoy]

It's (speed sensor) input is required to shift the trans, Is the speedometer working

 

[Murphy Clyde]

Thanks so much, it is working now!! The speedometer was working crazy, but now it is working just fine.