Another strange power door lock thread for ya

2

2K24RNR

New member
Greetings all,

I have power door lock situation not quite like the many I have read about recently on this and other forums. I have a 2002 SR5 4x4 with no remote start or immobilizer.

My issue is as follows:

Only the driver door will lock or unlock electronically. It works normally with the remote fob or the door panel switches on either front doors as long as the other doors are in a mechanically locked state.

If the front passenger door or the rear hatch are in an unlocked state the driver door still will lock with the remote fob and door panel switches but there is no beep. There is also a delayed softer mechanical noise coming from what sounds like the driver door lock. The unlock behavior of the driver door does not appear to be affected by the other doors. It always beeps twice when unlocking driver door. When I pulled fuse 39 and put it back in all of the doors locks appear to have unlocked so I don’t think I have actuator problems.

A bit of background. I bought a Tundra earlier this year so the 4Runner did quite a bit of sitting over the summer and fall but I tried to drive it for a few days every month. I think the 4Runner is a better winter rig for my area so this last weekend the plan was to get it serviced and ready to go for winter driving. Unfortunately, I let it sit too long this time, in freezing temps, and the battery was dead when I tried to start it. I measured about 500mV before connecting my jump start pack and started it. After a short drive I noticed the door lock issue and remembered popping the headlight bulb on my motorcycle when I used the same cheap jump start pack a few years ago when the 8 year old battery would no longer hold a charge. This jump start pack has an unloaded output voltage of 16.8 volts which seems pretty high to me. I have no doubt this is why the headlight bulb on the bike popped and now I’m wondering if I may have damaged the body ECU in the 4Runner?

None of the fuses my research has led me check are blown and everything other than 4 of the 5 power door locks are working fine. The power antenna wire has been disconnected for a few years so I really doubt that is related.

Any troubleshooting tips to help isolate the culprit? I have not pulled the Body ECU out yet and may not until spring if I need to. I’m not worried about soldering in a new relay if that is the fix.

Thanks in advance and Happy Holidays!

Rick
 
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Check the wire bundles coming out of the doors and rear hatch for broken wires. Check the rear hatch first as those area common issue.

-M
 
Yup +1 for your doors and rear hatch. With the issues most likely being in the drivers door and rear hatch. Extremely common with 20 year old wiring.

Sent from my SM-J337V using Tapatalk
 
An update:

After sitting for two days the brand new Interstate 24F battery was completely dead.

I disconnect the negative battery cable and charged it with a battery charger.
Once fully charged I put my multimeter in series with negative battery post and battery cable terminal.
The initial reading was about 9A but it slowly staring dropping until settling in around 550mA which still seems pretty high.
20201212_134749_800.jpg


When I pulled fuse # 39 the current dropped to 20mA which seems legit.
20201212_140700_800.jpg


I'm about to tear into the rear hatch wire bundle for a peek.

Thanks again for the tip guys!
 
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Everything looks good here :)

20201212_154343_C.jpg


The black/yellow wire and the thicker blue wires were pretty much fused together.

Separating them and wrapping the exposed wires with electrical tape seemed to take care of the excess current draw issue but the door lock issue remains. Only the driver door will lock and unlock electronically.

I'm gonna pick up some wire tomorrow to replace about 6" of the 'bending' sections then keep digging.
 
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Driver door wires look pretty good.

The small gray/black wire had a crack in the insulation so I replaced that section of wire. The removed section did measure good after I cut it out.

20201213_150021_1280.jpg


The same issue remains. If all of the doors are locked the driver door locks and unlocks normally with the fob. When I press the unlock button on the fob a second time I get the second set of beeps and I hear some kind of mechanical movement inside the driver door but none of the other doors make any sound at all.

If the rear hatch or front passenger door are unlocked when I press the lock button on the fob the driver door locks but there is no beep. When the driver door is locked and I lock the other unlocked door with my key the 'locked' beep goes off.

Also, since repairing the damaged rear hatch wiring all of the doors do not unlock as soon as I connect the battery or insert fuse # 39 like it was doing before the repair. The the two shorted wires must have been causing that.

I need to research some test points next.
 
2K24RNR said:
Driver door wires look pretty good.

The small gray/black wire had a crack in the insulation so I replaced that section of wire. The removed section did measure good after I cut it out.

20201213_150021_1280.jpg


The same issue remains. If all of the doors are locked the driver door locks and unlocks normally with the fob. When I press the unlock button on the fob a second time I get the second set of beeps and I hear some kind of mechanical movement inside the driver door but none of the other doors make any sound at all.

If the rear hatch or front passenger door are unlocked when I press the lock button on the fob the driver door locks but there is no beep. When the driver door is locked and I lock the other unlocked door with my key the 'locked' beep goes off.

Also, since repairing the damaged rear hatch wiring all of the doors do not unlock as soon as I connect the battery or insert fuse # 39 like it was doing before the repair. The the two shorted wires must have been causing that.

I need to research some test points next.
Click to expand...

What happens when you use a key? on the first turn your driver side should open the rest remain locked. a second all the locks should open.

Do all the locks unlock when you try to lock the rig with the key in the ignition. Basically running if you hit the lock to they immediately all unlock?


Also what happens when you use the key in the passenger door?
 
brillo_76 said:
What happens when you use a key? on the first turn your driver side should open the rest remain locked. a second all the locks should open.

Do all the locks unlock when you try to lock the rig with the key in the ignition. Basically running if you hit the lock to they immediately all unlock?


Also what happens when you use the key in the passenger door?
Click to expand...

I just ran out and checked.

When the driver door is locked the first turn of the key unlocks that door only as you said. The next turn does not unblock the other doors. I do hear the same mechanical sound from the driver door but no other sound from other doors.

Only the driver door unlocks automatically if I try to lock the rig with the keys in the ignition.

I am able to lock and unlock both front doors with the key in the front passenger door. However, the interior passenger door lock switch locks and unlocks only the driver door.

Thanks
 
2K24RNR said:
I just ran out and checked.



When the driver door is locked the first turn of the key unlocks that door only as you said. The next turn does not unblock the other doors. I do hear the same mechanical sound from the driver door but no other sound from other doors.



Only the driver door unlocks automatically if I try to lock the rig with the keys in the ignition.



I am able to lock and unlock both front doors with the key in the front passenger door. However, the interior passenger door lock switch locks and unlocks only the driver door.



Thanks
Click to expand...
Sure is sounding like the lock wire is not making contact outside the drivers door. This is why I was suspecting busted wires in the driver door jam. As they are only working mechanically. As they seem dead outside your door.

Sent from my SM-J337V using Tapatalk
 
brillo_76 said:
Sure is sounding like the lock wire is not making contact outside the drivers door. This is why I was suspecting busted wires in the driver door jam. As they are only working mechanically. As they seem dead outside your door.

Sent from my SM-J337V using Tapatalk
Click to expand...

You suspect the driver door lock detection circuit right?
The driver door is the only one that will lock or unlock without the key.
 
Correct the lock circuit. You have an issue in it somewhere. I was suspecting the driver door because it's the only one that functions properly.

You may have to pull the electrical wiring diagram out and go through that lock circuit to find it.

Sent from my SM-J337V using Tapatalk
 
brillo_76 said:
Correct the lock circuit. You have an issue in it somewhere. I was suspecting the driver door because it's the only one that functions properly.

You may have to pull the electrical wiring diagram out and go through that lock circuit to find it.

Sent from my SM-J337V using Tapatalk
Click to expand...

Yes I was looking at the wiring diagram this morning.

You don't think the 16.8V jump start pack with a totally flat battery could have done any component damage? How about the shorted wires in the rear hatch area? I sure am glad I looked there when I did. I'm a little surprised I didn't have a full blown fire back there.

Thanks again for all of the tips!
 
I really doubt it. The lock mechanisms are solenoids and they are mostly pretty tough.

It still seems to me like a broken wire somewhere start tracing it around and see what you find.

Is your fuse good? I would think that if the driver door works it most likely the circuit has power:)

Sent from my SM-J337V using Tapatalk
 
This is the lock detection circuit I focused on today. Inside the red box.

When the driver door is unlocked there is ~ 0 VDC at pin 12 of IF2 and pin 17 of B16. When the driver door is locked there is ~ 2 VDC at these same points.
The service manual indicates there should be 10-14 VDC or < 1 VDC depending on the state of the lock.

LockCircuits.jpg
 
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