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Home › Jeep › 1999 › Grand Cherokee Laredo, 4.0 S, AWD › Repair and Diagnosis › Body & Frame › Body, Cab Control Systems › Body Control Computer - Tests › Overhead Console Diagnostic Tests › Ambient Temp Sensor CKT Open

Ambient Temp Sensor CKT Open

  1. Disconnect ambient temperature sensor. Sensor is located on right side of front grille, next to headlight. Connect jumper wire between sensor harness connector terminals. Turn ignition on. Close all doors. If overhead console displays SHORT CIRCUIT, replace ambient temperature sensor. If overhead console does not display SHORT CIRCUIT, go to next step.
  2. Turn igniton off. Disconnect Body Control Module (BCM) connector. Measure resistance of Dark Green/Red wire between terminal No. 9 on BCM C2 harness connector and terminal No. 2 on ambient temperature sensor harness connector. If resistance is less than 2 ohms, go to next step. If resistance is 2 ohms or greater, repair open Dark Green/Red wire.
  3. Connect BCM connector. Connect jumper wire between ground and terminal No. 2 (Dark Green/Red wire) on ambient temperature sensor harness connector. Turn ignition on. Close all doors. If overhead console displays SHORT CIRCUIT, repair open Dark Green/Red wire. If overhead console does not display SHORT CIRCUIT, go to next step.
  4. Remove jumper wire. Turn ignition on. Close all doors. If overhead console displays OPEN CIRCUIT, replace ambient temperature sensor. If overhead console does not display OPEN CIRCUIT, go to next step.
  5. Turn igniton off. Measure resistance between ground and terminal No. 2 (Dark Green/Red wire) on ambient temperature sensor harness connector. If resistance is less than 5 ohms, repair Dark Green/Red wire for short to ground. If resistance is 2 ohms or greater, go to next step.
  6. Ensure ambient temperature sensor connector is disconnected. Turn ignition on. Using voltmeter, measure voltage between ground and terminal No. 2 (Dark Green/Red wire) on sensor harness connector. If voltage is greater than 4 volts, test is complete. If voltage is 4 volts or less, replace BCM.
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