electrical prob.

[lfdsteve]

Having an issue with my 71 formy. Was an auto, converted to a stick. My problem is even with both underhood harnesses disconnected, my acc takeoff on my fuse box goes hot when I turn on the headlight switch. I have two wires that come in hot to the switch plug. A red wire and a brown wire with white stripe. If I jumper either of these hot wires to the Brown wire at the switch plug, the acc terminal goes hot. To my knowledge, this terminal should only go hot in start and run positions of ignition. I am obviously feeding the acc from the wrong side but can't seem to figure out where.
Steve
I noticed this problem because my ecu for my Powerjection is powered off the acc terminal for key power and when the lights are on, the car will not turn off, and if the car is off, turning on the lights fires up the ecu thus tripping the fuel pumps.

[MrQuick]

Yes, Sounds like you are jumping (bridging) power to the ACC feed. Should be dead and the ACC power feed comes from the ignition switch to the fuse panel. If it isn't you might want to look into the switch or adjustment itself. Was it removed recently?

Theres a bunch of circuits on that headlight switch too. Many possibilities for backfeeding.

I would suggest running you feeds from your IGN side. Large pink.

I assume its a 71 Pontiac?

[lfdsteve]

Yes its a.71 pontiac. I have the schematic but it is impossible for me to tell which way the hot comes from. It looks from the diagram that the 12g red comes from the c on the 5 pin ign plug that it shows should be hot in run position, and a 14g red off the 4 pin b which also showed hot in run per diagram. Both run to switch.
I have a brown with white stripe that comes into hl plug that is hot also, is this supposed to be hot?
Also it dosnt do it if I unplug the rear harnes plug from the side of the fuse box. This would lead me to believe that the cross is between this plug and the rear of the car but I have not touched this harness at all. Could all this be caused by a.hot feeding back thru the ground?
I hate electrical thanx for the help

[lfdsteve]

Also if I send hot right from the battey down any of.the bulb wires front or back this happens??
If I send power down the top wire of the female plug receptacle on the side of fuse bux, I think this is the rear harness plug, it comes on as well.
It was an auto with basic gauges, I have converted to a stick, is there any wires that only the auto should.have or should I still be chasing my connections under the hood?

[lfdsteve]

Looking at the.diagrams I can't tell where the power for the acc comes.from. it is the bottom most blade on the fuse box but the diagram showed no where that it feeds from.
Also, as stated if I send power down the brown tail light wire, it comes on but if I.short battery positive to ground it does not so I assume this rules out a ground short.
I see several spots on the schematic where these two systems come together but can't imagine that I would need to separate them in the harness basses on options so the back feed must come from some where else.
1. I ran the black with red stripe to battery hot junction under hood when rewired, is.this not supposed.to be a full time hot run?

2. How many hot wires should be at the.headlight switch plug?

3. I loose the brown field wire once it goes into the bulkhead connector. Where does this end up?

4. There ate two points on the schematic, one says exc standard car, and the other says standard car only. Are they receding to a stick as standard or the base model? Could my problem lye within these tow options?

[MrQuick]

I'll look into it today and send you info tonight.

Yes, 10g from battery to junction is hot all the time. But where does the black and red wire go to? Is it just from junction to battery?

Is this an aftermarket harness?

[lfdsteve]

Yes the red with black stripe goes thru a fuse link right to full time hot at junction.It is mostly the stock harness, what I did was locate the battery to trunk. So I ran large red wire bat to switch, switch to solenoid, then to starter. Also ran oo ground from bat to block. Ran purple out of engine harnes back to solenoid then wire up to starter completing starter setup. Next I took alt out to a junction where I connected all the harness wires that were wired together from factory. Red with green fuse link,16 g red,black with red stripe with bok fuse link. The yellow with black stripe and black with orange stripe are taped off as I don't have power door or window. Brown field goes to Brown in harness and both charge and sensing leads go to my power junction. The only other change was to move purple neutral switch(auto trans) to clutch safety switch as I have a stick and the red that goes to the head light switch is run to a hot with a 10 amp fuse. Is there supposed to be two hot wires at the headlight plug? I have a red hot and a brown with white hot.
I ran another test and with headlight switch on I had 12 v at acc terminal but if I completed that circuit, ie I grounded harneses so mites came on, voltage at acc dropped to 2. Not enough to trigger edu and pump solenoid but enough to keep it on once I turn key off. I am also getting 2 volts at coil whith headlight switch on and if I start the car. The tail lights stay on but the headlights go out. Am I just chasing a bad ground as I don't have any lights, dash ect hooked up yet?
Ps After looking closer, it is my ign out that is going hot with the lights, not my acc. So same issue just my ign out, not acc out.

[lfdsteve]

Been at this all day, no joy. But
When I apply 12 volts to the brown terminal wire that is in the headlight switch plug, I get 2 volts at both my coil wire and the big pink wire so the leak has to be down that Brown wire but where has got me completely stymied...I look at the diagram and it just disappears in the fuse block.
Ps for giggles replaced ignition switch without change. Stl 2 volts

[MrQuick]

From your ignition switch Brown white trace is field feed @ alternater. Feeds into the warning lamp. This would explain your voltage drop w/ feeding it with 12v.
see figure 2 and 4
From your headlamp switch, brown wire feeds the parking lamp circuit. Brown and white trace is the ignition feed from the fuse panel and is fed by bat circuit on the ignition switch.

It would be better to feed your system with the large pink ign circuit. See circuit that feeds your original coil +. see figure 2A




can you email me pictures of what you are working with? [email protected]

[lfdsteve]

Good info thanks. I assume the picture you are asking for is which schematic I am looking at? I am using the one in the 71 manual but can scan it if you like.
I considered using the pink wire to power my ecu(assuming thats what you meant when you said "feed your system")but that shows the same 2 volts so I am afraid I will have the same issue.
One thing, there is only one bulb in the side marker/ headlight pigtale and it is a small side marker light. Is all that power feeding back thru the ground there?
thanks again
Steve

[MrQuick]

Hard to say, If you feed the brown and white @ your headlamp switch it will back feed to the fuse through it and then into your ignition circuit. Take a look at the 1st schematic above. Feed 12V to the opposite side of that fuse, what is your voltage now? I believe that circuit will not support all of the draws on it.