TheSamba.com :: View topic - Central locking system white and yellow shorting to ground

Sat Feb 18, 2023 5:10 pm

My central locking system works only on the driver side door, though there's a continuous ground through the brown wire out to the deck lid, and the red wire is always hot to connector T4 near the glove box. I haven't pulled the door panels.

However, I noticed that both yellow and white are always shorted to ground at the sliding door contacts and at T4.

That cannot be right. Or can it?

Seems to me the white and yellow should be intermittently hot when the key is turned in the driver or passenger door. Is that true?

Another question: where do you find the other (T3) connectors under the dash? Bentley is pretty vague on this.

Sat Feb 18, 2023 6:26 pm

Hi,

This resource from Gowesty is good, it will help with your diagnosis:
https://gowesty.com/blogs/article-library/power-door-locks-101

Sun Feb 19, 2023 8:31 am

That is a good article.

I was hoping to find some practical advice on where to look for a white and yellow short to ground between the driver side lock and the T4 connector just above the glove box.

What I don't get is how this could happen without blowing fuses when the driver side lock is actuated.

Sun Feb 19, 2023 10:11 am

continuity test is your friend

Sun Feb 19, 2023 3:52 pm

Unplug both front door motors and re test for your ground issue.

If anything, wiring issues happen at the boot, bc that's where wires flex.

Sun Feb 19, 2023 4:43 pm

Not sure if all central locking systems control all 4 door locks. Mine does, and if one lock gets stupid, they all get stupid. It has provided me many hrs of entertainment.
I'd suggest unplugging all but one lock, check for functionality, then do it for all the locks until one gives you grief. That's the one that needs loving...
It's a, mostly "love" relationship with the central locking system,, UNTIL something goes wrong.

Sun Feb 19, 2023 5:09 pm

Check for continuity for the DS and PS white and yellow at the connector behind the glove box. If the wires are OK it's one of the master actuators. I solved my power lock problems by installing an Amazon 4 door power lock kit.

Sun Feb 19, 2023 6:05 pm

My driver side lock works like it's supposed to so I don't think it's that. Could that actuator (near new from GW) fail such that it grounded both yellow and white wires--while it works fine to lock the DS door?

What I want to find is the T4 connector shown in Bentley 97.163. There's no mention of its actual location. T4a seems to be the one just above the glove box.

If I can find T4 I can test continuity between that and T4a. If it's "before" T4 that makes it look like the wires in the DS bellows or whatever you call that.

Anybody know where that T4 connector is? Right next to the fuse panel? In the middle of the dash somewhere?

Sun Feb 19, 2023 6:23 pm

do.dah wrote: Not sure if all central locking systems control all 4 door locks. Mine does, and if one lock gets stupid, they all get stupid. It has provided me many hrs of entertainment.
I'd suggest unplugging all but one lock, check for functionality, then do it for all the locks until one gives you grief. That's the one that needs loving...
It's a, mostly "love" relationship with the central locking system,, UNTIL something goes wrong.

Not entirely true, only if the masters (in the front doors) have an issue fighting each other. The salve motors don't cause any issues to others, just the masters.

Californio wrote: My driver side lock works like it's supposed to so I don't think it's that. Could that actuator (near new from GW) fail such that it grounded both yellow and white wires--while it works fine to lock the DS door?

What I want to find is the T4 connector shown in Bentley 97.163. There's no mention of its actual location. T4a seems to be the one just above the glove box.

If I can find T4 I can test continuity between that and T4a. If it's "before" T4 that makes it look like the wires in the DS bellows or whatever you call that.

Anybody know where that T4 connector is? Right next to the fuse panel? In the middle of the dash somewhere?

I'm not sure what they are called, but for each door out of the boot about 50mm, cabin side , you have the 4 pin connector to plug into the main central locking harness, which goes to the other door across the dash, following the crash beam below the heater box.
In the main harness, red goes to fused power, brown to ground. Yellow and White are just polarity reverser.
Behind the glove box is the 3 pin connector tee'd into the harness going to the rear slave door lock motors (actuators).
If you look carefully, the colors switch at this point, yellow becomes white and white becomes yellow going to the rear slaves, bc the actuation is in opposite motion.

It's very easy to work on these systems.

Sun Feb 19, 2023 6:57 pm

Ok, so T4 is right by the DS door. Thanks, that will get me going again. Looks like I'll need to drop the fuse panel and holder to access it.

Sun Feb 19, 2023 10:50 pm

Californio wrote: Ok, so T4 is right by the DS door. Thanks, that will get me going again. Looks like I'll need to drop the fuse panel and holder to access it.
Definitely. If you need to gain slack, close a bit the door on you while working in there.