Fuse 23 Blowing and not the usual culprits

[Senor_Taylor]

Hey everyone. I know this issue has been tackled a ton of times, but no threads I've found have helped me solve this issue. I picked this 90 325i Sedan up a couple of months ago and I'm trying to get it sorted. Everything is going well except fuse 23 blows every time I pull the headlight knob to the first click. I've unplugged every exterior lights and cleaned the connectors and checked the wiring on the right side of the vehicle and the license plate lights. I've checked both ashtray lights, the red and grey dimmer wire to the head head unit, multiple grounds, and replaced the headlight switch and nothing solves my issues. I'm at a loss to what the issue may be. I've pulled the gauge cluster and everything seems fine. Everything else works on the gauge cluster except the speedo, but I believe I wired the plug in backwards at the diff (separate issue).

Does anyone have any ideas? I can't drive this car at night until I figure this out.

Fuse 23 should be Dash lights, Right running lights, license plate lights.

SOLUTION LISTED BELOW

[IceWhite]

What if you unplug all that you have listed again, and then pull the headlight switch to check if the fuse blows. If it does not blow, leave the switch at the first click, then start plugging each connector again until the fuse blows. Hopefully that should help.

[Senor_Taylor]

What if you unplug all that you have listed again, and then pull the headlight switch to check if the fuse blows. If it does not blow, leave the switch at the first click, then start plugging each connector again until the fuse blows. Hopefully that should help.

I've already tried and with all exterior lights disconnected, the fuse still blows immediately.

[IceWhite]

According to the bentley manual: Fuse 23 is a 7.5a fuse.

It powers the following:
Instrument panel lights
Front parking lights (see also 22)
Rear tail lights (see also 22)
Rear side marker and licence plate lights
Active check control (see also 4, 6, 10, 21 & 22)
Rear defogger (see also 8)
Multi function clock (see also 12 & 21)
On-board computer (see also 10, 12, 21 & 27).

Try unplugging the Instrument cluster, Check control panel and OBC and let us know what happens.

[Senor_Taylor]

ISSUE RESOLVED.


The main loom for that circuit runs down the left side of the vehicle, then the wires go into the tail light on the passenger side and the license plate lights. This makes sense, but what I didn't know was that the wires continue over to the left side of the vehicle. I do not know why, because there is nothing on that fuse on the driver side of the vehicle in the rear. The red/grey wire was ever so slightly pinched by a bolt that was below the driver side tail light assembly. Fixed this and all of my issues were resolved.