what is this single wire coming through the firewall

Then why isn't this brown wire hot when the parking lights are on? Why brown and not light blue with red tracer like all the other light circuit wires? The switch will have a power wire going to the switch and a wire coming from the switch going to the relay...not two hot wires going to the switch

 

Jeff,
For the Sport lamps, the wiring has a plug with two wires to connect it just as you said. I just reconnected mine two days ago. The grabber harness has this plug which incorporates the wire that runs to the relay in the left foot well. After the relay, it changes to brown/orange and exits through the main harnes plug to the lamps. If you do not have a grabber harness, you dont have these wires and the two socket plug (1971). The sport lamp switch is also supplied by the brown wire so that you can not energize the relay unless the headlights or parking lights are on.

The lt blue/red is all the interior lights that are dimmed. The dome light is a black/lt blue

My diagram has a brown wire connected to the floor shifter light. I imagine it is for safety in that they want you to be able to see what gear it is in. I used a brown wire that was in the harness in the area of your picture to power my floor shifter light.

Strangly, my other diagram shows a lt blue/red as illumination for the gear selector. That might be a column shift only deal. I'm not sure.

The diagrams indicates that the brown wire is also for all the side marker lights as well as the license plate light. I dont know why you are not seeing power in the brown wire you referr to.





Micah

 

For some reason my phone will not allow me to post a picture,just trying to find a good 12 volt source for the pertronix ignitor and new coil. There is also a 2 wire connector on the firewall that is not being used also ,ckecked it wit my volt meter and it has 12 volts in the run position and also 12 volts while cranking I wonder if this wire would be ok to use .I also hooked that wire to the old coil with a jumper wire and it read 11 volts in the run position where the old positive wire read 5 volts in the run position and 12 volts when the wire was off the coil , I guess this means that is a resistor wire , any thoughts?

 

I called pertronix and they said 12 volts at the coil would be best , how have other people hooked it up , mine is a 1972 200 6

 

Use the existing wires coming threw the firewall . I will share a picture.

 

AFAIK there is no direct switched circuits under the hood...

What I did for my Street Fire setup was use the red/green resistance wire to operate a relay that powers the system, to go that route will be necessary to connect coil to the relay controlled power...

With only load of relay coil, voltage drop on resistance wire is approx .2v...

 

Curtis,
You should make yourself familiar with the harness diagram.
http://1bad6t.com/Maverick/repair/chassis_electrical_05.html#a

Micah

 

Micah-
My car is not a Grabber. It is my understanding that on a Grabber the only time the Sportlamps will come on is when the headlights have power...they don't come when only the parking lights are on. I may be wrong but this is why I'm thinking the single brown wire has something to do with powering the Sportlamp switch. I know after the switch is where the harness and relay is Grabber only. I don't know what is different in the wiring before the switch.

 

On my '74 one of these wires are hot in the start and run position . These wires were going to the emissions junk on the air cleaner.

 

Poster is talking about a '72...

 

Jeff,
I don't think the sport lamp option was available in '74. Didn't that disappear when the fat bumper came in and the grill lights (sport lamps) became the turn signals? If that is the case, there would no longer be sport lamp wiring even in a '74 Grabber. I'm not the expert on that since I don't have a '74.

'71 & '72, Grabbers had an entire engine compartment and interior harness that were specific to the Grabber. There was not an extra harness that converted a standard harness to a Grabber. Not sure if that was also true on the '70 but I suspect it was. I discovered this 17 years ago when I went to install the sport lamps in my non-grabber. I removed the entire harness from a Grabber to make the lights work as original.

Since then, I have spent some quality time with my harness. I even pulled it out and soaked it in hot soapy water to clean it up before I rebuilt the dash. I had to figure it all out to get my EFI, AOD, floor shifter, sequential lights and a few other things to work properly. I even had an NOS standard engine harness converted to Grabber spec. I'm still straightening out things and is the reason I was just reconnecting the sport lamps the other day.

The solid brown wire feeds the side markers. It is also the power source to trigger the sport lamp relay. Therefore, sport lamps can be on with the side markers as well as the headlights.

Micah

 

I know of a early Grabber in the junkyard that I can get the complete harness. This might be my best bet instead of trying my luck at reinventing the wheel.
Thanks for your time and help.

 

Sure!
If you don't use it, I'm bet you can sell it and at least rescue it.

I don't know if there would be any issue in using it on your '74, except for the turn signal switch. You could probably re-pin it and make it work.

Micah

 

I was thinking about stealing the wires I needed from the Grabber harness and using the Grabber fusebox and firewall plug (if the Sportlamp wires uses this plug)

 

Thanks for the photos, coming thru my firewall I also have another two wire connector,not connected to anything ,also 1 single wire coming thru the firewall, they all look factory, just wonder what they were meant for. Brown single wire does not have power going to it ,in any key position