1990 Volvo 740 4 cyl Two Wheel Drive Automatic 185, 00 miles
The transmission will not shift to fourth gear. The button on the shift knob and associated amber arrow enunciator is on. This was for heavy loads and now will not disengage. I have reset the fuse (which according to manual also controls backup lights). This was unsuccessful. At times after a few minutes of highway driving it will transition to fourth, but is unreliable.