Good day everyone,
I am hoping to get some help regarding an issue with my drivers side door lock. It seems that when the car is sitting in direct sunlight and is hot outside ( Im In Florida ) the door lock switch from the drivers side works fine and locks and unlocks both driver and passenger locks. However, when car is in shade or at night door lock switch is dead. The doorlock switch from the passenger side can lock and unlock both doors day or night. Additionally, the keyfob always unlocks the drivers door but not always both doors. Another mystery is that sometimes I close the door harder than normal and can hear the door locks cycle but they do not lock or anything. Below are a couple of things Ive done.

1. Ive changed the actuator on the drivers side.
2. I replaced the drivers side ECU and still the same.
3. Replaced battery in keyfob last week

Please let me know if you have any ideas of what I can check. I appreciate any help.

 

When you say the driver's side ECU, do you mean the MICU that is part of the driver's fuse box?

 

Pahonda,

Yes, that is correct I replaced the entire MICU piece that includes all the fuses.

 

I'd probably take a look at the driver's door switch. Check first if the connetor has any corrosion, It just sounds like an issue with the solder joints or contacts in the driver's door switch.

 

Good afternoon PAhonda,
I finally had a chance to look at the door switch, I didnt see anything really wrong with it. However, I found a video on YT about testing a window switch that is suppose to check for power on on the wires that go to the connector and my test light didnt light up. Its a 3 wire connector that goes on the lock switch. Its a green/red wire and a black/white wire. Both those wires also go to the door multiplex so I checked for continuity and there is continuity from the switch to the door multiplex. I am not good at reading schematics but I found one for the 99 and apparently there is an unlock replay behind the lower left dash? I will have to check for that apparently its near the keyless security control unit.

 

There isn't a relay to power those wires. The wires are directly from the MICU. Those wires carry 5V, so your test light might not light up with a 5V power source. Check using a volt meter.

 

Good morning PAhonda,
I did as you said and used my multimeter. I set it to 20V and backprobed both the green/red wire and the black/white wire. They both have 11.37V without ignition power. When I turn the ignition to ON voltage drops to about 11V. I checked continuity from the black wire ( middle of the connector ) to G200 ground (above left kick panel) and there is continuity. I see on the schematic a white/yellow wire from the door multiplex harness that serves as a battery input. I cant see anything else with battery power near by.

 

Reading throughh your post again. When you said you replaced the driver's actuator, what part did you replace? The electrical motor that pushes/pulls the door lock mechanism in the latch?

 

Yes, that is correct. I replaced the actuator itself. Part# 72155-S84-A11