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Discussion Starter · #1 · (Edited)
interior lights / fog lights

I need some help with B5 99 2.5Tdi 4Motion Auto. Interior lights are working manually, both front and rear, but they wont light up once i open the doors. I have repaired almost all of my door locks 3/4, 4th one was fine. I have door light in all of my doors which are working now, but the interior wont work. I checked CCM, there was one bad solder joint (cold one) which I repaired. All windows are working, alarm too where should be the problem ? :bowdown: Also I moved ground wire to another place. btw Someone poor was repairing cables from CCM before and I have to re-doit. Also yesterday I find out that one of the cables from rear light was unpluged so I plug it back and now once I press on brake my fog lights light up (dash icon too). :hmmm: I found some wiring schematics but I'm not sure about it. Cause i have 24-pin and 18-pin connectors in CCM unit. :cry: Thanks for any help :)
 

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You say the alarm and the windows are working. I assume you have "door open" indication on the dash (instrument cluster)? If you do, then the Comfort Canbus is working, thus the CCM should be activating its output that turns the interior lights on when you open the door.

That output is the blue/gray wire on the 23-position CCM connector, pin 16. The wire changes colors to brown/white in the red 10-position connector at the A-pillar connector station (beside driver's left foot), then goes to the lights (up in the headliner). The CCM connects this wire to ground when the doors are open to make the lights come on.

Since someone made some poor quality repairs, maybe they messed this one up, too. (These wire colors are from the US Bentley manual; they're probably correct, but no guarantee.)

Regarding the fog light: I assume you mean the rear fog light(s)? US Passats don't have rear fogs, and the taillight assemblies are different, so I can't help much with this. But apparently the brake light and fog light circuits are somehow connected together when you plug that connector in, and they shouldn't be.

The brake (and rear fog, AFAIK) circuits don't touch the CCM, though. The CCM is only wired to the turn signal circuits (so it can blink the turn signals when you lock/unlock your doors).
 

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Discussion Starter · #5 ·
You say the alarm and the windows are working. I assume you have "door open" indication on the dash (instrument cluster)? If you do, then the Comfort Canbus is working, thus the CCM should be activating its output that turns the interior lights on when you open the door.

That output is the blue/gray wire on the 23-position CCM connector, pin 16. The wire changes colors to brown/white in the red 10-position connector at the A-pillar connector station (beside driver's left foot), then goes to the lights (up in the headliner). The CCM connects this wire to ground when the doors are open to make the lights come on.

Since someone made some poor quality repairs, maybe they messed this one up, too. (These wire colors are from the US Bentley manual; they're probably correct, but no guarantee.)

Regarding the fog light: I assume you mean the rear fog light(s)? US Passats don't have rear fogs, and the taillight assemblies are different, so I can't help much with this. But apparently the brake light and fog light circuits are somehow connected together when you plug that connector in, and they shouldn't be.

The brake (and rear fog, AFAIK) circuits don't touch the CCM, though. The CCM is only wired to the turn signal circuits (so it can blink the turn signals when you lock/unlock your doors).
I dont have that indication on dash. Do I need to have it ? Is there any way I dont have it in my equipment ? Or is it default ? I bought the car with bad microswitches so I dont know if it even ever works. Ground might be the problem cause I cant get any Voltages from some cabels but once I tried ground on another place it works. Yeah I meant rear fog light, car is from germany, european cars have them. I understand that but it's weird that once I unplug it stops doing it, but once I turn on rear fog light they works. Im thinking about connecting interior lights with doors lights, cause door lights are working once I open the doors. But I dont know which one cable is for door lights. What you think about it ?
 

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This is a networked system, using Canbus...

There is a Canbus node built in to each door's window motor, one in the CCM, and one in the instrument cluster (plus a few others depending on year and options). (This is the Comfort Canbus, to be distinguished from the powertrain Canbus.)

When you open a door, the microswitch in the door turns the puddle light on directly, and turns on an input to the Canbus node. That door open status is reported over Canbus to the instrument cluster (to turn on the "door open" indication) and the CCM (to turn on the interior lights, among other things). There is no direct electrical connection, just the Canbus network.

That Canbus network is also how the "lock/unlock doors" and "raise/lower windows" signals get between doors and CCM. When you lock/unlock the doors from the keyfob, the keyfob transmits to the CCM, which then sends the lock/unlock signals to each door over Canbus. Thus, that's an easy test to know the Canbus is working. The "door open" indication on the cluster is a good indication, too. It sounds like your Canbus may not be working.

The Canbus is a small-gauge twisted pair of wires (orange/green & orange/brown). It's spliced in the floor harness, since it goes to all four doors, the CCM, and cluster. Since your floor harness has been poorly repaired, I'd look there first. Canbus is pretty forgiving, but do maintain the twist up to any splice, and make the splices cleanly. Crimp butt splices, if crimped with a decent tool, are my preference.
 

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My 2000 ROW Passat does NOT have door open indicators on the dash.

Positive voltage is supplied from the CCM through the same Red/Black wire to the door lights (puddle lights),
and Red/Blue wires spliced to the Red/Black wire supply power to the other interior lights.
The puddle lights are grounded by a micro switch in the door lock module.
The interior lights are grounded by their individual switch or the CCM, depending on the switch position.


"Interior lights are working manually, both front and rear, but they wont light up once i open the doors."
This indicates a grounding issue, either in the wires from the lights to the CCM, or more likely a CAN Bus communication fault.

You really should get a VCDS or dealer scan.
 
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