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.
Chart C-12, Engine Cooling Fan 2.8L TPI: Notes
The cooling fan is totally controlled by the ECM based on inputs from the coolant sensor and fan control switch. The fan should run if cooant temperature is more than 226Β°F (108Β°C). Battery voltage is supplied to the fan relay on terminal "E", and ignition voltage to terminal "C".
Grounding circuit No. 335 (relay terminal "B") will energize the relay, and supply battery voltage to the fan motor. Once the fan relay is energized by the ECM, it will remain on for a minimum of 30 seconds.
The fan control switch mounted, in the A/C high pressure line, will open when head pressure exceeds 200 psi (14 kg/cm2 ). This input causes the ECM to ground circuit No. 335. If a code 14 or 15 sets or the ECM is operating in the fuel back-up mode the ECM will turn on the cooling fan.
- With diagnostic terminal grounded, cooling fan control driver will close, which should energize fan control relay.
- If A/C fan control switch or circuit is open, the fan would run whenever A/C is requested.
- With A/C clutch engaged, A/C fan control switch should open, when A/C pressure exceeds 200 psi (14 kg/cm2 ).
NO RELATED
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.