Adding to this: for 03-07 models, the relay panel behind the junction box is replaced by a circuitboard ECU. My unlock function did not work, no door relays were found pulling the junction box and after replacing the whole thing, door lock/unlock functions were restored.
LX470 LC100 Electronic Key and Interior Door Lock Button Stopped Working (4 Viewers)
- Thread starter doober
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- 100 series key fob lx470
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I bought a used match from eBay and swapped it and it worked
Thanks for the reply.
I actually am thinking that the relay in the junction box is not my problem. What are the odds that all actuator motors are going out? Here are my symptoms:
Definitely seems to be triggered or made worse by warm weather. And each time I try to use the central locking/unlocking it gets weaker and weaker until I try again later.
When locking and unlocking with the fob, I can see the knobs trying and failing to flip.
When locking and unlocking with the key in the lock, only the door that I have the key in will flip. I can see the others trying and failing to flip.
-Exception: I can not unlock the tailgate at all with the key when I am experiencing issues.
I actually am thinking that the relay in the junction box is not my problem. What are the odds that all actuator motors are going out? Here are my symptoms:
Definitely seems to be triggered or made worse by warm weather. And each time I try to use the central locking/unlocking it gets weaker and weaker until I try again later.
When locking and unlocking with the fob, I can see the knobs trying and failing to flip.
When locking and unlocking with the key in the lock, only the door that I have the key in will flip. I can see the others trying and failing to flip.
-Exception: I can not unlock the tailgate at all with the key when I am experiencing issues.
Not the junction box/relays. Otherwise you wouldn't see the "knobs" or "tabs" or whatever it's called try at all.
Look up threads here that talk about the harness in the driver door breaking. A wire may be wearing out or already broken and barely touching... So the current is too weak to fully function. If the harness looks good, you may have to try to change the lock actuators and test each one.
... but it kind of sounds like a broken harness. If it is and if you solder, I would just replace the lines that are broken with similar gauge stranded wiring. Most would probably recommend replacing the whole harness.
Exact same symptoms here so I am curious to see what you find out. It should be cooling off here in CO soon so I am not in a huge rush to fix it.
Same here...........following. I changed the master switch in the door (drivers door switches) and it seemed to have improved. But not confident that was the complete fix until I have a larger sample size of time.
Providing an update on the relay change. That wire harness retainer that covers the top aft nut was a pain in my @$$. I left the top harnesses connected, but I disconnected all the lower ones. All in, including removing the front seat so I can work comfortably-ish, it only took 2.5 hours start to finish. I changed all 3 relays, but unfortunately it did not solve the problem. At least I don't need to get in there again (fingers crossed).
What year? LC or LX?
99 LC. I pulled the harness from the door jamb and examined the wires (second time I've done it since I've owned the truck first time was for running new speaker wires) and the harness is good. Getting steady 12V direct from the fuse panel, so I ruled out the components in the door. I was trying to rule out the cheaper options before I tackle the instrument ECU. Will be looking into that next.
Well darn it! I was really pulling for that to be the issue. I have noticed that the first time in the day that I lock the doors, is the strongest action I get. The more I use it, the more "lazy" the action gets. Particuarly the drivers door. I am starting to wonder if a less than 100% charged battery could be involved. My battery is giving me zero symptoms of needing to be replaced. But I checked it with a battery tester and the results were "REPLACE". It's 4 years old. But it still does this with the locks while driving, so the altenator would make up for a low battery one would think. I almost feel as something in the mechanisms needs to be lubricated.
Definitely let us know your conclusion.
Could it still be the door switch in the driver door if I still have issues locking and unlocking with the key in the passenger door?
Probably not, unless all the wiring goes through that switch somehow.. I had a couple of windows buttons not working correctly, so I needed the new switch anyhow.
If it's just the passenger door, you'll need a new lock motor in that door. Are you saying it works fine from the lock buttons but not the key? And with the key... Are you talking about the remote or just the physical blade in the door?
I have 99 LX470. The FOB key is not working (not a battery issue) to open remotely. If I unlock the driver's door with the key, the alarm would trigger. However, I can unlock the car from the passenger side or from the back door. Inside the car, the lock and unlock switches work on both driver and passenger side. Any suggestion on where to start troubleshooting is welcome
Anyone know where to find a schematic for the 03-05 relay box? Trying to troubleshoot my 04 LX. Key fob locks/unlocks all doors but driver, and driver door lock button locks/unlocks all doors but driver. Physical key is only way to unlock driver door from outside.
The lock button triggers alarm when door is open.
Anything else worth considering?
TIA.
The lock button triggers alarm when door is open.
Anything else worth considering?
TIA.
03+ uses a ecu board instead of all those relays. Sounds like your driver door lock motor is out.
I agree, I thought the same, but we replaced the lock actuator/assembly with a new aisin part. Did not resolve. So found this thread, and realized the ecu is different from the relay assembly of the pre-03 models and therefore more difficult to troubleshoot. So is the next step to find a used ECU from a similar year that’s being parted out, or can you find them new?
I found mine on eBay, but you have to really match the pictures to what you have. On the black fuse cover, you'll have a large letter printed. Mine says F, and seems to differ from most of the 03+ (H) on eBay. Also, mine is missing the 30A BATT CHARGE fuse, which in my car it's on the passenger side junction box. If you suspect this part to be your issue, you could try finding one with return options. I paid about 220 for mine after tax, and I would be responsible for shipping both ways if I chose to return it.
What is the P/N for this? My 07' LC is having a similar issue. I can start the vehicle with the master key but the lock/unlock/panic functions do not work.
