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2007 Honda Civic Sedan LX AT
Problem: Driver Side Master Power Door Lock/Unlock button does not work.
Passenger side lock/unlock button will unlock all doors; including driver side.
Key fobs / Remote Start key fob will lock and unlock all doors.
Hence door lock actuators are good.
Power Door Locks fuse is good.First thought, door lock switch is broken, tested continuity between lock pin and ground, unlock pin and ground, continuity when pressing either; switch is good. Swapped with another lock and unlock switch; same problem, not working.
Secondly, checked power going to both lock and unlock. Voltage provided to both lock and unlock.
Remaining options(maybe nicked/cut wire); checked door hinge, all wires seem to look good; but will have to check continuity later on when it gets warmer outside. (Highly doubt wires are nicked/cut)
Lastly, (and I hope not) there is a “Super Driver’s Master Locking Relay” located somewhere behind the cabin fuse box; 5 pin relay that might have failed… Only problem is dealerships I have talked to can’t find the part number, nor the location. One dealership did say if everything I did check is correct, and it really is the relay, the relay is actually non serviceable; and it’s fused to the fuse box.
Here’s my dilemma, and I’ve tried to do some diagnosis. Really don’t want to drop the entire fuse box with the cold weather at the moment, but will go about that route unless someone can find me an alternative.
Thanks in advance for any advice!
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Why not try leaving the switch connected and doing a back probe voltage drop on the switch output for the door lock? This way you can see what kind of voltage is coming out of it. If it’s low, then you might look into your wiring problem theory. If you have good voltage coming out, then perhaps there is something to this relay theory. Honestly, I don’t know if it’s a relay you’re looking for. I believe the BCM is what controls that action. If you had a bidirectional scan tool you might be able to activate the locks from there to confirm the operation of the other components in the system.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
Good luck and keep us posted on your progress.
Just took a quick look at the electrical schematic for you. From the looks of it the drivers and passenger side do use separate relays. The relays are not serviceable, and are integrated into the multiplex integrated control unit. All other unlock switches in the vehicle are run through the passenger side relay.
Hope this information was helpful.
Thanks for the reply Eric, but it totally went right over my head; my brain is trying not to accept the fact that it’s a PITA to fix. With your information, I would still need to pull apart majority of the wiring, and fuse box probably. I’ll definitely tackle that when it gets warmer.
What blows my mind is the relays are non serviceable, would you by any chance know if I could test the relay even though it’s non serviceable?
If there is any test and it confirms it’s the relay, would the only way to fix this to be with a new fuse box?
Thanks in advance.
I would check fuses 10 and 25 in the under-dash fuse box. Honestly don’t expect either of them to be blown. Fuse 10 will be hot when in on or run, fuse 25 will be hot at all times. Other than that the wires that run from your switch should be a blue and yellow wire that run back into a connector C752 your A pillar, and then you should be able to trace them into your under dash fuse box. You can check for issues in the wiring and C752. To be honest I’m leaning towards your fuse-box needing replaced, but if you have some time you could be positive by checking that wiring.
As always I hope this information proves helpful.
[quote=”misturjason” post=92665]Thanks for the reply Eric, but it totally went right over my head; my brain is trying not to accept the fact that it’s a PITA to fix. With your information, I would still need to pull apart majority of the wiring, and fuse box probably. I’ll definitely tackle that when it gets warmer.[/quote]
The article I attached for you goes over voltage drop testing. You likely won’t have to tear the wiring all out. That’s the beauty of doing voltage drop tests. That said, I suspect an issue with the integrated control unit. These have issues from time to time. Forget about the relay. If the relay was bad, it wouldn’t work all the time. You stated it does work when you use the other switches. This indicates that the relay is good and the problem is elsewhere in the circuit. I believe the integrated control unit is either not getting a signal or not sending out a command. This is were a bidirectional scan tool is helpful. You can send the commands and look for inputs with one of those. It makes diagnosing something like this much easier.
Good luck and keep us posted.
Late update; got this fixed after taking it to the dealership and being told I have too many mods on my car and he’d rip out everything before diagnosing the car. He did waste 2 hrs of my time by doing the same parasitic draw tests that I told him I already did. All in all a useless trip to honda to be told by a technician exactly what I told him before I started.
Regardless 1 hefty bill and a few more hours of self diagnosis; I decided to do continuity test between each wire… literally each wire to the MICU. Found that 2 ground control wires; get this; the door lock and unlock were tapped into for my remote starter (ha..ha…ha… remote starters…) It was somehow pulling current… and draining my battery; when disconnected it no longer disabled my master lock and unlock buttons and fixed the parasitic draw…
Took it to the remote start installation shop I went to; they’ve never seen this problem before; but made some tweaks and got it to work… All in all; no clue how ground controlled wires can draw power out of no where.. but yeas…
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