Mechanics

NO!! SPEEDOMETER 94

1994 GMC C1500

Electrical problem
1994 GMC C1500 V8 Two Wheel Drive Automatic 202541 miles

Hello have a 94 GMC C1500 5.7 4L60E the trans won`t shift and the MPH don`t work. Check for AC volt at the speed sensor. The volt go up with higher engine RPM, check for AC volts at the speed buffer coming from the speed sensor have AC volts there so the wiring good. Also check for DC volt coming out of the buffer my chart tree says 1.0 to 2.5 DC volt I have 5.04 DC volts I have changed the buffer and the ECM also clean the G109 and G108 ground. So any GM guys out there that can help thanks
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MAGIC2756
June 25, 2010.



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