DrWood

I'm out of ideas and could use some help!
I recently bought a 2002 2dr civic lx and the power door locks weren't working. I figured it was something simple and since I know a bit about electrical and have done small repairs it would be easy to fix.
When I try the switch nothing works and there is no sound at all. The passenger door doesn't try to lock when I pull the handle and lock the drivers door. First I was thinking it was a bad switch. There is power on both sides of the 3 wire connector but none at the actuators when the switch is engaged. I tried jumping power from both sides of the switch connector which should work the actuators? but still got no power there. I jumped from the battery to both actuators switching polarity and they lock and unlock so I think they are good.
So now I can't figure out why I'm not getting power through the switch.
I found a wiring diagram and there are several relays somewhere along the power wires but it doesn't say where to find them. All the fuses related to the locks are good so I'm kinda lost at this point. Any help would be appreciated!

ezone

the power door locks weren't working.

One or both?

I figured it was something simple

Famous last words.

and since I know a bit about electrical

I installated my own radio too. It even worked when I gots done.

LOL.


When I try the switch

Which one? (I can't see inside your car)

Did you know there are more switch contacts inside the power lock actuator too?

nothing works and there is no sound at all. The passenger door doesn't try to lock when I pull the handle and lock the drivers door.

Does the actuator in the drivers door work?


There is power on both sides of the 3 wire connector

but none at the actuators when the switch is engaged.

I tried jumping power from both sides of the switch connector

which should work the actuators? but still got no power there.

Mistakes #1-4.

I jumped from the battery to both actuators switching polarity and they lock and unlock so I think they are good.

Good.



So now I can't figure out why I'm not getting power through the switch.

Because power doesn't go "through the switch".
This is pictured in my wiring diagram.

I found a wiring diagram

If you could really read your wiring diagram, you should be able to figure out why I said "mistake" up above where you said you jumped the power on the P/L switch wires.

You got "power on both sides" of a 3 wire switch.
Either that made no sense, or you completely ignored an entire wire.
What is the 3rd wire? (I already know what it is supposed to do, I'm trying to figure out your thinking here.)

Again: Power doesn't go "through the switch".

Keep in mind here too, you are apparently stabbing power into a computer and it sounds random. You could fry it pretty easily. Not cheap.

and there are several relays somewhere along the power wires but it doesn't say where to find them.

I think you may not have the correct wiring diagram, or it may cover more than what you have in your car..
There really aren't any relays involved in JUST the power lock system.
There is a multiplex control unit. (It could have relays inside it, but there aren't any that are external.) It operates the lock motors. It also decides if the lock motors shouldn't be run, and can stop them if it thinks that would be appropriate.

Now, if the car has the factory accessory keyless kit that would have been added on by a dealer, that gets different wire diagrams. The add on security system gets more wire diagrams too. Relays are now involved if the security got added.


All the fuses related to the locks are good so I'm kinda lost at this point. Any help would be appreciated!

Fuses:
Engine compartment fusebox
#2, 7, 9, 16,

dash fusebox
#10, 20,

If it has keyless, there are 2 more fuses bundled with its own harness.


This should get interesting. HTH

DrWood

2 door car neither door works.
there's only one door lock switch on the drivers side.
I figured there were switch contacts inside the actuator but since both of them work fine when I feed power directly I don't think that's the issue.
I don't know much about car wiring specifically but if the switch is anything like the dc switches I use at work then I was thinking that the middle wire in the switch connector was the common and the ends were bringing power in for up and down. My meter reads 12 volts on either end wire while grounding off the middle wire. I tried jumping from the middle wire to an end wire. Jumping across seems like it would just bypass the switch. I know the relays on the diagram are part of the multiplex unit and that's what i'm wondering about. Maybe something is wrong in there? I've ruled out most the simple stuff like bad switch or bad actuator cause everything seems to function fine when isolated. You mentioned a couple fuses I didn't check so i'll do that. I wondered if maybe the actuators were wired in series and if something was wrong with the connector on the drivers side maybe it's not sending power to the passenger side but i'd have to buy a new actuator to know for sure since I don't know how to test it. I'll keep messing with it (carefully) thanks for the input. If I cleared anything up here and it gives you a better idea i'd love to hear some more ideas,

DrWood

Oh and no security system. Don't know about wireless remote. When I bought it it didn't have one with the keys but who knows. Some retard who owned it before me splice in a new head unit with no harness and its a mess with twisted wires everywhere. It shorts out the radio a lot but I don't know if that would even matter cause it's probably on a different circuit. Unless a grounding short was messing something up but I don't know if that's even possible

ezone

I figured there were switch contacts inside the actuator but since both of them work fine when I feed power directly I don't think that's the issue.

The contacts in there are what triggers the power lock in the other door when you manually lock the drivers door.
I am not looking in the diagram right now, I believe on a 4 door it can only lock them, while on a 2 door it can lock and unlock.

the middle wire in the switch connector was the common

A diagram will show it is a ground.


and the ends were bringing power in for up and down.
My meter reads 12 volts on either end wire while grounding off the middle wire. I tried jumping from the middle wire to an end wire.

Your terminology must be confusing me. The switch does not control the lock actuators directly. The switch only makes a request in the multiplex control unit (MICU).

The MICU is looking for either one of the two wires to get grounded (black is ground). This will (should) trigger lock or unlock.

Lock is disabled if the door is open while the key is in the ignition...
The remote can unlock while a door is open. It can't lock while a door is open. All remote functions are disabled if the key is in the ignition.


Jumping across seems like it would just bypass the switch.

Yeah, if you do it right.




I know the relays on the diagram are part of the multiplex unit and that's what i'm wondering about. Maybe something is wrong in there?
Mine doesn't actually show MICU internals.
If you have issues with it, Honda sells you the fusebox.

The multiplex system has a self diagnostic function. If you have a good service manual, there are a whole bunch of checks for the multiplex system that you should probably be checking into.
I.E. switch input tests: You have 12v on the switch wires, and a ground, so I know the 2 wires are connected to the control unit. If the control unit does not display the correct response to that switch input through the designated indicator, then you should know what is next.


I've ruled out most the simple stuff like bad switch or bad actuator cause everything seems to function fine when isolated.

Not looking easy now.
*rolls eyes*




You mentioned a couple fuses I didn't check so i'll do that. I wondered if maybe the actuators were wired in series and if something was wrong with the connector on the drivers side maybe it's not sending power to the passenger side

No. They are separately and independently controllable by the MICU.



but i'd have to buy a new actuator to know for sure since I don't know how to test it.

That'd be a bad move. You already tested it.
You said "I've ruled out most the simple stuff like bad switch or bad actuator " and "both of them work fine when I feed power directly".

Would you rewire a house because of a bad light bulb?
You are done here.



I'll keep messing with it (carefully) thanks for the input. If I cleared anything up here and it gives you a better idea i'd love to hear some more ideas,

See above. Do all of the self checks and input tests, etc. before condemning anything.
Hell, use a test light and go through every last fuse in both boxes.

--------------------------------------
Got issues with any of these other things?
C&P from Honda site:

The system controls the function of these circuits:

• Entry light control (ignition key light and ceiling light)
• Wiper/washer (including intermittent wipe and park functions)
• Interlock system
• Keyless/power Door Lock
• Key-in reminder
• Meter assembly, temperature gauge, and indicator lights
• HVAC (compressor and fan control)

DrWood

Holy crap I'm having problems with a bunch of those other things!
My dome light doesn't work with the door, my wipers don't work on intermittent, my warning beep doesn't work when I leave the lights on or the keys in, my ac fan and compressor won't work even though there's pressure and the pump works when I direct wire it. Pretty much everything you mentioned. Are they all connected to the multiplex switch? Maybe I AM in over my head haha. I guess if one thing fixed them all that would be awesome. I figured each was a separate problem. I was about to order a bunch of little things like a wiper switch and a blower motor resister. Guess I'll break out the meter and test light and get to work.

ezone

My dome light doesn't work with the door, my wipers don't work on intermittent, my warning beep doesn't work when I leave the lights on or the keys in, my ac fan and compressor won't work even though there's pressure and the pump works when I direct wire it. Pretty much everything you mentioned.

*I* didn't mention it.
It is published information.

Many of those could also have their own separate problems too.
Example-- the drivers door jamb switch broken is a common dome light and warning beeper problem.


Are they all connected to the multiplex switch?

It's the body systems computer, not a switch.

Maybe I AM in over my head haha.

Maybe...


I guess if one thing fixed them all that would be awesome.

It could happen. Only one thing affects all of those different systems.
Don't guess.


I figured each was a separate problem.

That's what you get for random figuring.


I was about to order a bunch of little things like a wiper switch and a blower motor resister.

Those things can be easily tested and proven good or bad.
And the blower uses a power transistor, not a resistor.

AutoZones entire business model is based on the fact that most people don't or can't diagnose.
And they want dirt cheap parts, quality be damned.

Guess I'll break out the meter and test light and get to work.

*blinks in disbelief*

oscas3000

replace the inner fuse box under the dash and all those problems will go away..