door locks

[Elephant_Berls]

My mom has a 99 explorer 4 door, well i went down a paticurly bumpy road one day (gravel road with washouts and such) and the next day i got in the car the door locks went crazy. i mean it was like a ghost was in there locking and unlocking the doors. I was scared the motors would burn out, it wasnt really like a lock and unlock more of a noise coming from the locks. I think they were locking. then trying to relock over and over. I stoped and checked every door lock switch none were stuck.. i got back in with the annoying locking noise. I held the door lock in unlock position and it went away. But the doors would not lock or unlock. That lasted about 2 mins and it came back. Then i hit a bump and it went away.

Next day i get in the car turn the key on and there the locks go again this time i found the bigest badest bump there is in town and rammed it. Well that solved it. But im afraid itll come back. Paticualry while the car is parked some where and drain the battery. What could be the problem? My mom considerd bringing it to the shop but they will probaly charge 3-400 dollars for some simple thing

 

[Howard]

Sounds like you have a bad connection somewhere possibly by the lock/unlock switch in the drivers door. You would have to pull the panel to check.

 

[onelasttry]

loose ground in the circut.

 

[Elephant_Berls]

how the hell would i track something like that down?

 

[onelasttry]

ford's work off of a 5 wire positive door lock system. There is only one true ground. you will either have to work your way through the circut to find it, or head to a local car audio store and tell them to find it.

 

[Elephant_Berls]

Im gona wait here and see if someone knows where its at :smoke:

 

[Elephant_Berls]

Originally posted by onelasttry
ford's work off of a 5 wire positive door lock system. There is only one true ground. you will either have to work your way through the circut to find it, or head to a local car audio store and tell them to find it.

haha im glad to hear that. Is there any chance it could be a positive short or maybe wire loose.? Im hoping its the negative so i dont have to take apart every door to see. But u never know with my luck

 

[onelasttry]

well, in a way, it could be the positive, but it isnt likely. here's how it goes down inside the circut:

the system is grounded at a central point. each of the grounds run to the doors and to the switch. on the other side of the switch is the hot wire. the switch is a double pole double throw switch. that means when it throws the hot, it also throws the ground to the other side of the switch.

how does this differ from other vehicles? well, in most vehicles...nissan for instance, a set of relays are used to operate the doors and only two wires are run instead of 5. the two wires are the ground for the unlock and the ground for the lock. the relays are hot all the time and when it see's a ground from the switch it kicks the lock.
the switch is a single pole single throw switch, rather than a DPDT switch since it only has to throw one current wire instead of two.

reason i said that was, in a situation such as that when a neg trigger is used, grounding one wire will cause a trigger, however in a ford, both wires float until the switch is hit, which complete's the circut.

now knowing that, you stand to reason that the only way the door locks can freak out is either 1.- the switch contacts are worn and are so close together they are touching OR 2.- the main ground is loose and is making the doorlocks unstable.

now, i am no self proclaimed expert on ford doorlocks. However i have owned two car audio stores, and have been installing for 13 years total. so i am passing along my long history with rewiring and repairing them. unfortunately, i do not know where the main ground would be on your model. I also cannot rule out that the switch isnt faulty in some way, and it could only be the main switch since it is the only one that operates all the doors.

 

[onelasttry]

let me add that if your model came with factory keyless, the module that controls it could have a ground problem inside of it.