Possible causes

– Faulty Low Speed Radiator Fan Relay
– Low Speed Radiator Fan Relay harness is open or shorted
– Low Speed Radiator Fan Relay circuit poor electrical connection
– Faulty Electric Fan
– Faulty Front Control Module (FCM)

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Radiator fan inoperative
– Possible engine overheating

P0691 JEEP Description

The Front Control Module (FCM) has detected a short to ground in the cooling fan relay 1 control circuit