LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Alfa Romeo >> 1987 >> Spider Graduate >> Repair and Diagnosis >> Engine Performance >> System >> Fuel Injection System - BOSCH AFC >> Testing >> THERMO Time Switch
April 5, 2026: LEMON Manuals is launched! Read the announcement.

THERMO Time Switch

Remove electrical connector from switch. Measure resistance as indicated in resistance table. If any resistance value is not to specification, replace switch.

THERMO TIME SWITCH RESISTANCE

Temperature: °F (°C) Terminals Ohms
Below 86 (30) G & Ground 25-40
Below 86 (30) W & Ground 0
Below 86 (30) G & W 25-40
Above 104 (40) G & Ground 50-80
Above 104 (40) W & Ground 100-160
Above 104 (40) G & W 50-80
  1. Warm engine to normal operating temperature and stop engine. Using a thermometer, measure temperature of coolant. Disconnect negative battery cable and sensor electrical connector.
  2. Connect ohmmeter leads to both terminals of sensor. Readings should be as specified for corresponding temperatures. See COOLANT TEMPERATURE SENSOR RESISTANCE table. If not, replace coolant temperature sensor.
COOLANT TEMPERATURE SENSOR RESISTANCE

Temperature °F (°C) Resistance (Ohms)
68 (20) 2100-2900
122 (50) 700-1000
176 (80) 250-400