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.
1989 Mercury Cougar LSFACTORY OEM SERVICE PROCEDURE
Temperature Vacuum Switch (TVS)
Using a vacuum pump, apply 16 in. Hg of vacuum to the motor side of the switch. Ensure vacuum switch meets specifications. See VACUUM SWITCH SPECIFICATIONS table.
VACUUM SWITCH SPECIFICATIONS (1)
| Color | Switch Closes °F (°C) | Switch Opens °F (°C) | ||
|---|---|---|---|---|
| White | 50 (10) | Above 76 (24.4) | ||
| Brown | 15 (-9) | Above 30 (-1) | ||
| Red | 60 (18) | Below 50 (10) | ||
| Purple | 40 (4) | Above 55 (13) | ||
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Factory Service Tools
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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.