Low power to one fog, unloader relay?

[Qube]

Symptom, driver (left) side fog light is low voltage.

Discoveries:

Reads only 9.5v.
Removing fuse for that side does NOTHING. Stays at 9.5v.
Only time with no voltage is ignition off.
Even in position 1 without lights on, gives 9.5v.
Unloader relay (KLR, or terminal R) gets warm (normal?)
REMOVING the above relay makes voltage 0... not sure if does same to passenger fog
OBC didn't work very rarely. Now it doesn't turn on.
Deep cleaning cycle for headlamp/windshield stopped working.

Comments? Is the relay bad or something else? If it's the former, what's the P/N? Only markings on the unit are:

TOP:
602.039
61.36
1388745

BOTTOM:
87
30
86
85

[Qube]

Well, disenheartened... I disconnected the HID from the fog harness on that side and capped the end for the time being. Damn F/Fog warning :|

Went for a drive to set off some parkade car alarms, then noticed on my return trip, the OBC was working again.

Stopped, ignition off and noted TEST9 voltage at 12.49.

I dread to think what would happen when I set the CODE and the OBC doesn't work.

[Qube]

Perhaps the issues are all unrelated and because it's 4AM, I'm off my rocker? It IS only one side fog light... the unloader R seems to be working, whatever that is. The little magnet moves with ignition on/off. I have no idea what I'm doing.





Functional details of the LKM-B:

In standby (low beams off), there are 9.8V at the fuse. If you remove the fuse or the bulb, the on-board computer alerts failure.
The 9.8V looks like some kind of current limiting circuit (current not checked).
When the light is switched on, there are 12V at the fuse and of course at the bulb.
In case the relay (or the soldering point) is defective, there are 0V at the fuse and no (!) warning from the on-board computer.

Bayani De Guzman did a creative fix: The e-magnet on the relay was not strong enough to overpower the resistance of the spring. What I ended up doing was switching the relay of the fog lamp (seated next to it) with the low-beam, since that the low beam was more important and always used. For the broken relay, I loosen the tension on the spring to make is less restrictive and now all lights are working again.

[Qube]

One more thing before I sleep... damn it's 5AM...

It worked intermittently before. Fog would be on, then switch off after a while, but no LMK error... presumably because the voltage was too low for the ballast but sufficient to not give off an error. I'm going to check at various times tomorrow to see if the voltage gets back up to the 11.5v+ range tomorrow.

[Paul in NZ]

why do you think the intensive clean has stopped?Are your fogs HID too?Perhaps its a short.grounf issue,i think all those wires are around the same area,ie front bumper front fog intensive clean tank/pump

[attack eagle]

good luck... I too hate diagnosing electrical at night when my brain is tired.

[Qube]

I might just say to hell with it... remove the HID fogs (sigh), then pull the wiring from the other fog to run a standard halogen (yellow bulbs)... then put a resistor pack to get rid of the F/Fog Light OBD message. Yeah, the lazy man's way out until I get an e39 540i

[Qube]

Ok it's getting late and I'm getting stupid before I do the stupid thing above...

WHY is it:

1. tossing out 9.5ish volts with ignition on but not even fogs on? Other side is 0 when fog switch off.
2. why just the one side with this behavior?
3. why when turn on fog switch, then pull out unloader relay R, the faulty side goes 0 volts but the ok side still giving out 12v as normal?

[Qube]

Maybe I'll just use the relay harness and wire both up directly to the battery... or just the one. Yeah, sounds like a viable option. Still need something to get rid of the F/Fog Light if I do...

[Qube]

I realize I'm just talking to myself now... 3AM...

I have so many relay harnesses... going to just wire it up to the good side and to the battery. On the bad side, toss in a resister pack (like for LEDs) to fake the F/Fog Light away. Yep. That's settled.