Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1985S10/T10 BLAZER 4WD L4-151 2.5LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSSHIFT LIGHTTESTING AND INSPECTION
1985 Chevrolet S10/T10 Blazer 4WD L4-151 2.5L
Shift Light: Testing and Inspection
1985 Chevrolet S10/T10 Blazer 4WD L4-151 2.5LSECTION Testing and Inspection
Chart C-8B - M/T Shift Light:
Wiring Diagram For Chart C-8B - M/T Shift Light:
CHART C-8B - MANUAL TRANSMISSION SHIFT LIGHT CHECK
Circuit Description:
The ECM uses information from the following inputs to control the Shift light:
^ Coolant temperature
^ TPS
^ VSS
^ RPM
The ECM uses the measured RPM and the vehicle speed to calculate what gear the vehicle is in. It's this calculation that determines when the Shift light should be turned on.
Test Description:
1. This should not turn "on" the Shift light. If the light is "on", there is a short to ground in CKT 456 wiring or a fault in the ECM.
2. This should turn "on" the Shift light.
3. This checks for an open in the Shift light circuit or a faulty ECM.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.