Need Help Identifying a Couple Wires
11-23-2009, 01:05 AM
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Need Help Identifying a Couple Wires
This is a question to those electricians who have a copy of the wiring diagrams, as I myself do not. The car is a 1982 5-speed. I've been tearing through the car trying to identify and fix potential wiring issues, and as is often the case it seems like my worst enemy is a previous owner. I have found a couple issues of wires where they have been severed, and then re-attached questionably, and I wanted to know what these wires are, because there's a chance they could have to do with my drains and inop brake lights
The first I believe is interior lighting grounds, they're running along the B pillar behind the passenger side rear interior quarter panel. It was 4 brown wires and 5 black wires all connected, however the two outside black wires had been frayed, 1 of them had been severed, put back together and taped up, and the other one had some insulation missing and a few frayed wires. I think there's the possibility the very long and poorly installed screws from the speaker grill could have cut the wire, and may have even been making contact with the copper itself.
The other wire I've found that has been tampered with is a black wire with a blue stripe that is loomed at the bottom just inside the passenger rear interior quarter panel, runs the length of the hatch area floor and it splits off to either side, of the rear of the car. I think this may be linked to my recently inoperable stop lamps, and I'm going to clean up the connection and make sure it's solid and not just a bad tapejob.
That's it, sorry to be such a bother I just don't have the documentation I need to find out what these wires are to. I appreciate your help and maybe this can help someone else
The first I believe is interior lighting grounds, they're running along the B pillar behind the passenger side rear interior quarter panel. It was 4 brown wires and 5 black wires all connected, however the two outside black wires had been frayed, 1 of them had been severed, put back together and taped up, and the other one had some insulation missing and a few frayed wires. I think there's the possibility the very long and poorly installed screws from the speaker grill could have cut the wire, and may have even been making contact with the copper itself.
The other wire I've found that has been tampered with is a black wire with a blue stripe that is loomed at the bottom just inside the passenger rear interior quarter panel, runs the length of the hatch area floor and it splits off to either side, of the rear of the car. I think this may be linked to my recently inoperable stop lamps, and I'm going to clean up the connection and make sure it's solid and not just a bad tapejob.
That's it, sorry to be such a bother I just don't have the documentation I need to find out what these wires are to. I appreciate your help and maybe this can help someone else
11-23-2009, 10:28 AM
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All brown wires are grounds.
All black wires are power.
Interior lights have two ground wires - solid brown that is a ground so that you can turn the individual light on, and brow with a white stripe that is a switched ground, leading to the door or hatch switches.
The black/blue wires are the backup lights.
The brake light wires are red/black or black/red, depending on which side of the connector you are on.
Check Fuse #7 and its connectors very carefully - this is the brake light fuse.
Up thru 1983, the brake lights are operated by twin pressure switches on the bottom of the brake master cylinder. From 1984 - up, the brake lights are operated by a simple plunger switch mounted on the brake pedal under the dash.
The earlier brake light switches do double-duty, operating both the brake lights and the brake pressure warning signal. These switches can cause some problems.
The switches are identical - one in each hydraulic circuit. They are single-pole, double-throw switches. This means that you have only one circuit (single pole) thru each switch, and that the switch chooses one of two outputs (double throw).
Each switch has three connections: power, central warning computer, and brake light.
Not Activated
There is a power feed into each switch. When the switch is not activated (no pressure in the brake circuit) the power isn't hooked to anything.
When the switch is not activated, the central warning computer and the brake lights are connected inside the switch. Nothing happens, since there is no power applied on either circuit.
Activated
When the switch is activated by brake hydraulic pressure in one of the circuits, the central warning computer connection is broken, and the brake lights are hooked to the power feed. This removes the central warning computer from the circuit, and puts power on the brake lights.
(This might be easier to visualize if you think of three wires: one for 12 vdc, one to the brake lights and one to the warning computer. The lead that goes to the brake lights is connected to the one to the warning computer until brake pressure pushes it off of that wire and over to the one going to power.)
All three leads go to both switches.
When you apply the brakes, both switches should activate. Both switches disconnect the warning computer and connect the power to the brake lights. The brake lights come on, and no signal is sent to the warning computer, so it is happy.
If only one switch activates (either no pressure on one side of the brakes, or a bad switch), then things change.
On the switch that is not activated, the brake light circuit is still hooked to the warning computer.
On the switch that activates, the brake light circuit is hooked to 12 vdc.
The brake lights come on.
In addition, power flows on the brake light circuit back to the non-activated switch. Since in this switch the brake light circuit and warning computer are hooked together, 12 vdc is applied to the warning computer circuit. This set the Brake Pressure Warning light.
If you have a bad brake light switch, I strongly suggest that you replace both switches. (P/N 113 945 515 G)
All black wires are power.
Interior lights have two ground wires - solid brown that is a ground so that you can turn the individual light on, and brow with a white stripe that is a switched ground, leading to the door or hatch switches.
The black/blue wires are the backup lights.
The brake light wires are red/black or black/red, depending on which side of the connector you are on.
Check Fuse #7 and its connectors very carefully - this is the brake light fuse.
Up thru 1983, the brake lights are operated by twin pressure switches on the bottom of the brake master cylinder. From 1984 - up, the brake lights are operated by a simple plunger switch mounted on the brake pedal under the dash.
The earlier brake light switches do double-duty, operating both the brake lights and the brake pressure warning signal. These switches can cause some problems.
The switches are identical - one in each hydraulic circuit. They are single-pole, double-throw switches. This means that you have only one circuit (single pole) thru each switch, and that the switch chooses one of two outputs (double throw).
Each switch has three connections: power, central warning computer, and brake light.
Not Activated
There is a power feed into each switch. When the switch is not activated (no pressure in the brake circuit) the power isn't hooked to anything.
When the switch is not activated, the central warning computer and the brake lights are connected inside the switch. Nothing happens, since there is no power applied on either circuit.
Activated
When the switch is activated by brake hydraulic pressure in one of the circuits, the central warning computer connection is broken, and the brake lights are hooked to the power feed. This removes the central warning computer from the circuit, and puts power on the brake lights.
(This might be easier to visualize if you think of three wires: one for 12 vdc, one to the brake lights and one to the warning computer. The lead that goes to the brake lights is connected to the one to the warning computer until brake pressure pushes it off of that wire and over to the one going to power.)
All three leads go to both switches.
When you apply the brakes, both switches should activate. Both switches disconnect the warning computer and connect the power to the brake lights. The brake lights come on, and no signal is sent to the warning computer, so it is happy.
If only one switch activates (either no pressure on one side of the brakes, or a bad switch), then things change.
On the switch that is not activated, the brake light circuit is still hooked to the warning computer.
On the switch that activates, the brake light circuit is hooked to 12 vdc.
The brake lights come on.
In addition, power flows on the brake light circuit back to the non-activated switch. Since in this switch the brake light circuit and warning computer are hooked together, 12 vdc is applied to the warning computer circuit. This set the Brake Pressure Warning light.
If you have a bad brake light switch, I strongly suggest that you replace both switches. (P/N 113 945 515 G)