Electrical Puzzle

[marlabuck]

:argue:...Got a question about how the electrical is set up on a park brake...my 73' RR's park brake light was working before I goofed up and cut the socket wire too close and well...another story...anyway, got a new socket thanks to Paul...but there is still no joy...I have power to the plug in that goes on top of the brake...and there is another plug in wire above it that also shows to be a hot wire as there is juice to that at the same time as the other plug in...now there is a third wire that is not a plug in but heads north up into the neither regions of the dash...so 3 wires control the electrical...2 are hot and the third is???...I have power to the wires when the brake is off but no power when the park brake is engaged...is something backwards besides me? Marla

 

[marlabuck]

Okay so I'm thinking ummmm...leave the plug in wire alone..the one directly on top of the park brake pedal...tap into the wire that is the plug in type that is above the park brake up high for a hot wire...and the third wire should be the ground...tap into those 2 wires and everything should be right...or maybe not...Marla

 

[jessipup]

would you like a wire diag from the service manual 74
should be the same. Or if you dont speak thst language I coule help translate

 

[tpodwdog]

marla....i dont know what the hell ya done...lol....if all you did was cut the socket wire too short....and you replaced it with the exact same one,,,,and it was all working b4 you cut it...and now its not????unless you DIDNT replace it with the exact same one????. IM BAFFLED.

 

[Ron 73]

I know its large, but lower right corner you'll see your switch, see if you can trace the wires so you know which one is which.. If you save this to your computer, you probably have a program to enlarge it to see better.. Hope this points you to what you need..

 

[jessipup]

Most likely
That switch should have only one wire that goes to it and it should be hot to ground all the time the ignition is in run ( and Possable in ACC mode)
So the 12v comes from source runs in to and out of the indicator light on the dash. From there it goes to the switch looking for ground to complete the circuit and light the lamp.
But the 12v from source to lamp, from lamp to switch does not normally find ground because it is a normally open switch and only finds ground when switch is engaged by setting the parking break, then it lights the indicator.
The whole circuit should read hot all the time and if the wire is working this way. when you touch the wire to ground the lamp will light.
If not...there goes the fuse.
Test the switch by setting your meter on the ohm scale and look for continuitity whit the switch resting (not depressed) I suspect you will find no continituity.
And again with the switch depressed I think you will find continuitity.
This test will tell you if the switch is good and if my theory is correct

 

[marlabuck]

Most likely
That switch should have only one wire that goes to it and it should be hot to ground all the time the ignition is in run ( and Possable in ACC mode)
So the 12v comes from source runs in to and out of the indicator light on the dash. From there it goes to the switch looking for ground to complete the circuit and light the lamp.
But the 12v from source to lamp, from lamp to switch does not normally find ground because it is a normally open switch and only finds ground when switch is engaged by setting the parking break, then it lights the indicator.
The whole circuit should read hot all the time and if the wire is working this way. when you touch the wire to ground the lamp will light.
If not...there goes the fuse.
Test the switch by setting your meter on the ohm scale and look for continuitity whit the switch resting (not depressed) I suspect you will find no continituity.
And again with the switch depressed I think you will find continuitity.
This test will tell you if the switch is good and if my theory is correct

Really really appreciate the time you spent on this problem...you explained it in a concise manner...I will check it out tomorrow...Marla