Power mirrors not working / wiring inside door damaged - 1988 911

[Phony930]

Hello,
I am pretty handy at turning a wrench, but just never learned wiring very well — hoping I can get some help sorting out an issue on my 1988 911.
I bought the car last year and the power mirrors don’t work, never have under my ownership. I can’t adjust them manually to where they should be — trying to fix that for safety primarily.
I pulled the drivers door card and found nothing at all attached to the mirror adjustment switch. I found wiring inside the door with modern pink insulated spade connectors so it looks to have been modified at some point. I also found some of these wires were damaged or not connected to anything.

Photo attached (photo won’t load from my phone, will try from computer — wire colors in question are:
1) brown
2) black / purple
3) yellow
4) black/white)

— could someone please explain to me like I am 5 how to go about finding what wires they may be for, what wires should be going to the mirror adjustment switch, and if they are the same?


P.s. any way to just manually adjust the mirrors? I would be ok with that too if this wiring repair gets too deep. They don’t seem to adjust manually in my attempt.

[Phony930]

Photos finally loaded…

[wazzz]

All I can say is never trust those wiring diagrams from the Bentley manual, they are mostly wrong.
Get the proper factory wiring diagram for your car.

[zuch]

I have an 85 and the wiring is different, but going by the attached diagram, black with violet is coming from fuse 5 and should be 12v when the key is on. It feeds terminal 1 on your switch. Brown is ground and goes from pin 4 on the switch to pins 4 and 5 on the mirror and also goes from the switch to a hard ground point on the car. There are no yellow or black with white wires in the diagram. We will figure those out after.

Test the black with violet for power with the key on, then trace yellow and black with white and tell us where they go. Next figure out which branch of the ground network we are looking at. You can go ahead and make all of the power and ground connections if they are indeed power and ground like they should be. Maybe add a picture of the wires going into the mirror and those coming into the door. You got this.

[WMichelsen]

Those look like wires to the mirror adjustment 4-way rocker switch.

Here's a pic from my '87. I recently got it back from paint (thus a bit of over-spray).
If you want more pics of stuff, let me know. It's a good time.

[Phony930]

Originally Posted by WMichelsen

Those look like wires to the mirror adjustment 4-way rocker switch.

Here's a pic from my '87. I recently got it back from paint (thus a bit of over-spray).
If you want more pics of stuff, let me know. It's a good time.

That’s great thank you.
Can you ID the colors that are hard to see in that pic?
The three middle look like:
Yellow
Brown
Black/white

Could you confirm the far left and far right?

I will try to get back in there tonight to explore more.

Thanks for the replies to everyone!

[dictoresno]

Originally Posted by Phony930

That’s great thank you.
Can you ID the colors that are hard to see in that pic?
The three middle look like:
Yellow
Brown
Black/white

Could you confirm the far left and far right?

I will try to get back in there tonight to explore more.

Thanks for the replies to everyone!

the upper part of the 4th wire looks like its red, only the last 2 inches looks black. could that be a red/white and the 5th wire looks like white/blue.

[dictoresno]

Originally Posted by Phony930

Photos finally loaded…

The black/violet definitely goes to the fuse panel. I know that for sure since mine was disconnected by accident, causing my mirrors to not work and I needed to follow it and reattach it. all browns are grounds. your wire setup looks like a mix of the 84-85 and the 86-89 lol.

[wazzz]

As I said above, the Bentley diagrams are wrong. You can keep chasing your tail if you like,
but page 970-92 titled "Mirrors 1986-1989" is actually showing diagram for MY 84-85 and page 970-91 titled "Mirrors 1984-1985" is actually showing diagram for MY 86-89. The internal diagram for the joystick on this page seems to be wrong too.

[dictoresno]

Originally Posted by wazzz

As I said above, the Bentley diagrams are wrong. You can keep chasing your tail if you like,
but page 970-92 titled "Mirrors 1986-1989" is actually showing diagram for MY 84-85 and page 970-91 titled "Mirrors 1984-1985" is actually showing diagram for MY 86-89. The internal diagram for the joystick on this page seems to be wrong too.

I agree. I was just showing the diagram for the heck of it. The only one that I’m sure about is the black/violet.


Sent from my iPhone using Tapatalk

[WMichelsen]

Originally Posted by Phony930

That’s great thank you.
Can you ID the colors that are hard to see in that pic?
The three middle look like:
Yellow
Brown
Black/white

Could you confirm the far left and far right?

I will try to get back in there tonight to explore more.

Thanks for the replies to everyone!

I pulled the switch out the corner window slot to get better access, and scraped off as much of the paint over-spray as I could. Here are a couple better pics with annotation for wire colors (as best I can determine).

[Phony930]

WMichelsen — amazing, thank you.
I’ve had some long work days but am hoping I have an hour or two of focus to make progress tonight. Will update when I have something… thanks again all!

[Phony930]

Hey, look at that… found the missing wiring. The wiring was broken/cut and the connector had been pulled back out of the door into the body of the car in front of the firewall hiding within lots of other wiring. No idea why that got messed with but cough cough possibly from an accident repair a long time ago? Either way, I’ll get this patched back in and hopefully that fixes things and there aren’t other issues. I’ll report back!

[WMichelsen]

Nice when mysteries get solved

[Phony930]

Ok the switch works now — but I think the gears on the passenger side motor are stripped. Dang.
If the mirror glass moves freely side to side when you press lightly on it, but doesn’t move with the motorized switch… is that the problem?
Is the only solution a $250 motor replacement? There was some chat about 3D printing a replacement gear but didn’t see that it ever happened…

[Phony930]

I messed with it some more, seems like the mirror glass popped out of one of the two small sockets behind it — I was able to pop it back in and mostly gain control of the mirror adjustment, but it does seem like the gears may be at least partially stripped unfortunately. I was able to get some adjustment out of it though and have it in a usable position so I’ll call that good for now.
Thanks for all the help everyone! Forums are still the best for this kind of thing.

Next project: getting my reverse lights working.

[EC900]

The gears may just be dirty or gummed up from non-use. When I bought a R side mirror to aid view, I was able to bench test the motors for operation with a 12v tool battery before assembly, seemed stiff but maybe that’s the way it operates. I never bothered to re-wire (no harness). Did you open up the unit to get a look inside?
Manual adjustment w/o using the motors, the mirror glass was stiff enough to withstand door slams. Good enough to set and forget.

[PopsRacer]

couple things - motors can go bad, plastic bits can fall apart.. just be ready for something else to be wrong even after it is wired up properly. Here are the factory wiring diags for the 88 mirrors:

[wazzz]

Even the factory diagrams have errors. In the first pic above, the SWITCH POWER WINDOW legend is to be read as "SWITCH FOR OUTSIDE MIRRORS" or similar.
I'm currently working on my own edited version of the diagrams for 88 Carrera where I'm adding some fixes in red and changing some of the text. I started from a pdf copy of the German wiring diagram, which is higher resolution than what I found so far. If anyone is interested I can send them on or post a link. Not finished yet though.

[PopsRacer]

Hi - I have the original diagrams for the '88 and can get a high res scan taken of them if that would be helpful? My goal honestly is just to help get good info out there if I can. I have the whole set for the '88 except for the fuse panel where an '86 is the most recent I have, but it’s the same as far as I can tell. Let me know if I can help. Cheers