Looking for help with under dash wiring.

[OLD MAN]

I am cleaning up and putting my 80iS back together and am stuck with interior wiring.

I removed the Air close to 25 years ago and the somewhere along the way also removed the backup light wiring as they had cut through and shorted out at the gear shift hole.

I have spent a week now looking at the wiring diagrams in the Haynes manual and a lot of the wires (color codes) do not match what is in my car. Including the wire for the horn button.

My manual says back-up light wires are Blue/white and Green/white - I have no such wires in the area at all - not true but all the blue/white wires go to the lights for ash tray and lighter. I do have cut wires in the area that are Violet/white, orange/yellow or faded Red/yellow and brown. But the violet/white is a brake light wire for sure as shorting it out fries the brake light fuse.

The horn push button wire is listed as brown/green by the manual only brown/green wire I have going up the steering column has a white plastic connector on it and is connected to a matching connector on the turn signal switch with a gray or white wire in it.

Near the center console area with the going no where violet/white, orange/yellow and brown wires (all factory banded together) is a free one by itself 14ga blue wire going no where.

Anyway I am stumped!

Any and all help is needed.

[tlapham]

All I can recommend is to take your rear internal lens covers off, see what the reverse light wire colors are and you should be able to trace it down. There are no relays, so the switch wires should be exactly the same unless there is a splice somewhere under the carpet.

[OLD MAN]

All I can recommend is to take your rear internal lens covers off, see what the reverse light wire colors are and you should be able to trace it down. There are no relays, so the switch wires should be exactly the same unless there is a splice somewhere under the carpet.

Thanks - will do this tomorrow when I recover from my distress of working on it for a week..... LOL

[amarino]

The horn push button wire is listed as brown/green by the manual only brown/green wire I have going up the steering column has a white plastic connector on it and is connected to a matching connector on the turn signal switch with a gray or white wire in it.

I don't know about everything else, but I found the same mistake with my horn when messing with my car over the holidays. Unplug it from the turn signal switch and leave that side unplugged. The brown/green wire needs to plug in to the back of where the horn mounts. There will be a connector just sticking out.

https://www.bimmerforums.com/forum/s...8#post29917388

...
The hard part was having to take apart the dash to figure out why the button on the steering wheel wasn't working. After some reading of the Electrical Troubleshooting Manual and multimeter on beep mode checking continuity we finally traced it down to the brown/yellow with white plastic cover over the female spade connector not being plugged into the back of the spring loaded "brush?" that rubs against the back of the steering wheel. Instead that was plugged into another matching white plastic cover over a male spade connector that goes to the turn signal / high beam switch. Couldn't find that referenced in the ETM and everything still seems to work without it plugged into anything so it's just hanging out in there for now.

Attachment 618728 Attachment 618730

Anyone know what that other white connector that goes directly to the back of the turn signal / high beam switch is for?

Attachment 618729

[320iAman]

Not that many wires here Darryl. Left and Right back up light are connected by blu-wh wire and brown wire, the blue-white wire runs to the back up light switch on the transmission, the second wire at the back up light switch Green White goes to the fuse box and connects to a 8 amp fuse--white, under supplemental fan relay fuse and next to the horn relay.

Randy

[autox320]

All else fails you know what to do. Just find your ends and run new wire. Less stressful especially if someone has been hacking around. Wish I took a pic of the E30 dash wiring we took out one time. Compounding stereo installs so cut back to bare harness and did it much cleaner.

[amarino]

Sorry to bring this back up but I noticed this on a car at the junkyard that looked like it hadn't been messed with. The white wire with white connector coming off of the turn signal switch doesn't look like it goes anywhere. On this car it was just wrapped up against the harness.

IMG_20180410_091310.jpg

[Tom D]

..... wiring diagrams in the Haynes manual and a lot of the wires (color codes) do not match what is in my car........

My manual says back-up light wires are Blue/white and Green/white - I have no such wires in the area at all -
* FUSE TO TRANS = GN/WT
* TRANS TO LAMPS = BU/WT


all the blue/white wires go to the lights for ash tray and lighter.
* GR/BU WIRES UNDER THE DASH = FROM HEADLIGHT RHEOSTATE TO DASH ILLUMINATION (ASHTRAY, CLIMATE CONTROL PANEL, INSTRUMENTS, ECT)

I do have cut wires in the area that are Violet/white, orange/yellow or faded Red/yellow and brown.
VI/WT = FUSE 12 TO BRAKE SWITCH, RADIO, DIGITAL CLOCK

But the violet/white is a brake light wire for sure as shorting it out fries the brake light fuse.
* TRUE

The horn push button wire is listed as brown/green by the manual
* VI/BK = FUSE 15 TO HORN RELAY
* BN/YL = HORN RELAY TO SLIP RING
* BK = SLIP RING TO HORN BUTTONS
* GN/YL = RELAY TO HORNS

only brown/green wire I have going up the steering column has a white plastic connector on it and is connected to a matching connector on the turn signal switch with a gray or white wire in it.
* BR/GN = OIL PRESSURE SWITCH TO OIL LAMP, SERVICE REMINDER SWITCH
* BR/GN = LEFT DOOR SWITCH TO SEAT BELT SWITCH

TURN SWITCH
* GR/YL = FLASHER TO TURN SWITCH
* BU/RD AND BU/BK = TURN SWITCH TO TURN LAMPS

THE ONLY BR/GN WIRES I FOUND ARE LISTED ABOVE AND THE TURN LAMPS HAVE NO BR/GN WIRES IN THE CIRCUIT. IF ITS WIRED THAT WAY FROM THE FACTORY IT MUST BE EITHER A DEAD END OR AN ACCESSORY NOT USED ON ALL CARS


Near the center console area with the going no where violet/white, orange/yellow and brown wires (all factory banded together) is a free one by itself 14ga blue wire going no where.
* VI/WT = RADIO
* OR/YL = ?
* RD/YL = ? ....... OR MAYBE IT'S YL/RD = FRONT SPEAKER OR A.C. BLOWER
* BR = GROUND
* BU = HEATER BLOWER OR ELECTRIC MIRROR?

old man, I'm just seeing this tread for the first time, sorry. I've looked through the wiring diagrams and have answered your questions within the quote above, hope this is no longer needed, but in case it is.......

[OLD MAN]

Thanks Tom - Still having a couple of issues so this will help!!

How have you been Tom? Hope all is well. Is your son still in AZ?