2003 Yukon XL Denali: 3 months ago rear passenger doors and rear cargo door would not lock with door switch nor remote. All five doors unlock fine from any source. I replaced the rear lock relay last month, then all door locks operated fine. This past week the same symptom began again: front door locks operate fine, rear doors unlock with power but don't lock. Being curious, last night I removed both lock & unlock relays. In this condition the front door locks operate fine, rear door locks neither lock nor unlock. I then installed both original lock & unlock relays (not the recently purchased relay); all doors lock and unlock properly. There is no apparent difference in the resistance to operate any of the locks manually. What else should I look for? Really frustrating not knowing when the locks will lock or not.
Also, is there a way to lock the rear cargo door manually? I've not found it.
Also, is there a way to lock the rear cargo door manually? I've not found it.
