Plastic Electrical Connectors Under Fuse Panel

[James]

Currently reassembling much of my interior on my 73 CS.

There are 4 plastic wire connectors below my fuses. What does this power? Is it window stuff?

Sorry for no photos of said wiring; at work, rattling my brain on why my windows only work 5% of the time. Took the car for its first drive in almost a year and a half two days ago, and I actually manually rolled the window down halfway with the white plastic gear. Only piece of the dash installed was the gauges and their accompanying wood. Fun on Highway 1.

 

[Ohmess]

If you mean the clear, butt to butt connectors, I believe a number of important circuits go through there, including the load shedding relay which is part of the window and heater blower circuits, the front headlights and more.

 

[James]

If you mean the clear, butt to butt connectors, I believe a number of important circuits go through there, including the load shedding relay which is part of the window and heater blower circuits, the front headlights and more.

Yea, that sounds like it. Directly below the fuses, behind a relay. Is that the load shedding relay? Sorry, electrical is almost always really difficult for me to understand/trouble shoot.

 

[Ohmess]

No, the relay in front of those connectors is for a/c. The load shedding relay is on the left fender, immediately behind the wiper relay.

 

[Layne]

There's actually 2 sets of the butt connectors there in the same area, one has 4 pins and one has 5. All are for the front harness of the car: the engine, headlights etc. None are directly related to the windows, although I believe Ohmess is right about the load shedding relay being routed through there. I doubt that's related though, or you would be complaining that your headlights, blower motors, etc also don't work when the windows don't work. Also the power for the entire car comes in through there. There are two heavy red wires from the starter terminal, one goes directly to the fuse box and the other is in those butt connectors. I can't remember which powers what exactly. But again, whichever one goes to the windows also goes to a lot more things. The windows actually have two circuits (left and right) coming off separate fuses in the fuse box. If both sides are working and not working at the same time, you would need to look upstream of the fuse box most likely. I can't think of anything that effects those two circuits without effecting anything else though. These two wires are in a separate wiring harness that comes up from the driver's floor board next to the main harness, should be easy to locate. If you unplug them from the back of the fusebox (not so easy) you could apply power directly to them and see if the windows run. Each window has it's own ground point, which are very sketchy like all ground points on the car. If the 5% functionality does not apply to all windows at the same time, could be that all 4 ground points are not working.

 

[bavbob]

I was told by a vintage BMW repair guy who works mostly on 2002's that the aged vintage BMW fuse box is the source of a lot of things non-functional. I sprayed the crap out of mine with electrical contact cleaner and swapped out all the fuses with new and multiple systems came back to life. It was also the source of my faulty starter in my "Starter won't shut off" post since the starter relay was seeing 2 volts and not 12...till the fuse box was cleaned.

 

[James]

There's actually 2 sets of the butt connectors there in the same area, one has 4 pins and one has 5. All are for the front harness of the car: the engine, headlights etc. None are directly related to the windows, although I believe Ohmess is right about the load shedding relay being routed through there. I doubt that's related though, or you would be complaining that your headlights, blower motors, etc also don't work when the windows don't work. Also the power for the entire car comes in through there. There are two heavy red wires from the starter terminal, one goes directly to the fuse box and the other is in those butt connectors. I can't remember which powers what exactly. But again, whichever one goes to the windows also goes to a lot more things. The windows actually have two circuits (left and right) coming off separate fuses in the fuse box. If both sides are working and not working at the same time, you would need to look upstream of the fuse box most likely. I can't think of anything that effects those two circuits without effecting anything else though. These two wires are in a separate wiring harness that comes up from the driver's floor board next to the main harness, should be easy to locate. If you unplug them from the back of the fusebox (not so easy) you could apply power directly to them and see if the windows run. Each window has it's own ground point, which are very sketchy like all ground points on the car. If the 5% functionality does not apply to all windows at the same time, could be that all 4 ground points are not working.

Thanks for this.
Yea, all 4 windows will work 5% of the time and 95% of the time none are working. I have cleaned all the grounds, and I've figured it's upstream from the fuses, just haven't known where to start. When I unscrewed the fuse panel I was amazed at how complex everything looked behind there (at least to me). I guess I need to find those two wires.

 

[James]

I was told by a vintage BMW repair guy who works mostly on 2002's that the aged vintage BMW fuse box is the source of a lot of things non-functional. I sprayed the crap out of mine with electrical contact cleaner and swapped out all the fuses with new and multiple systems came back to life. It was also the source of my faulty starter in my "Starter won't shut off" post since the starter relay was seeing 2 volts and not 12...till the fuse box was cleaned.

Good idea.

 

[autowerks]

are you talking about butt connectors with semi clear cover? one black one red and I think a brown?

 

[deQuincey]

most of these questions can be better addressed if the guy that searchs for advice posts some pictures
coupes not only hold different versions but they have been heavily modified during the years
i believe that everybody has a mobile phone these days,...
:-0

 

[James]

most of these questions can be better addressed if the guy that searchs for advice posts some pictures
coupes not only hold different versions but they have been heavily modified during the years
i believe that everybody has a mobile phone these days,...
:-0

I'll do that when I get back to where the car is stored in a few days

 

[Tony.dreamer]

I think it is more important to James to find the source of his problem with windows than to know what the connectors are for .
I am no expert by no means on E9 coupes , or electrical issues in general, however I can tell you stories about my other older cars with similar issues......
I would start with the most basic and simplest inspections/ cleaning .....
Regardless of what brands of car, with problems like you describe I would first get a fine brass brush (tooth brush size) and electrical contact cleaner and remove all fuses and clean and brush both ends contacts of the fuse box and replace the fuses with new ones. Inspect and clean all 4 contact points of the battery cables. Then I find the ground contact on each window and remove, inspect and clean them(which you already have done). From that point forward if your problems still persist it would be very helpful to know the electrical diagram of the car. But I would use test light and check to see if I get power to each window motor checking for bad switches or bad relays....