Also dead, no power.

[zachmac]

New data point:

With every fuse pulled, including unplugging the one to the combination relay and the cigarette lighter, I still get a drop from 12.9 volts to .6 volts when I turn on the ignition. i think that means that I just eliminated all wiring off the fused side of the box, correct?

[jimincalif]

With every fuse pulled, including unplugging the one to the combination relay and the cigarette lighter, I still get a drop from 12.9 volts to .6 volts when I turn on the ignition. i think that means that I just eliminated all wiring off the fused side of the box, correct?

Makes sense. You said the car will crank and the headlights work, so that verifies the brown, red and blue wires at the ignition. The black at the ignition is fed from the hot side of the fuse box (F9), which is fed from F10, whic is fed directly from the alternator terminal. When the switch is turned on it connects the black to the pink going to the coil and the the hot side of F1. This is from the diagram, does this correspond to what you see in your car?

So what is happening with the switch is on?

The wiring diagram shows a jumper of sorts between the hot side of F10 and F9, what does this connection physically look like? Could it be failing such that you see 12v when there is no load, but due to high resistance the voltage drops when a load is applied?

I think you said you already measured the voltage drop at the box with the coil disconnected?

Could there be a fault in the ignition switch that is diverting current to something? I don't see how as you'd probably see evidence of this in something else coming on our shorting out? What happens if you jump the black wire to the pink at the ig switch connector block bypassing the switch?

This is a tough one.

[zachmac]

[/quote]This is from the diagram, does this correspond to what you see in your car?

MY WIRING IS AS PER THE DIAGRAM AND YOUR DESCRIPTION

So what is happening with the switch is on?

The wiring diagram shows a jumper of sorts between the hot side of F10 and F9, what does this connection physically look like?

I THINK IT IS A PHYSICAL CONNECTION BUILT INTO THE BOX AS THERE ARE NO WIRE JUMPERS

Could it be failing such that you see 12v when there is no load, but due to high resistance the voltage drops when a load is applied?

COULD BE BUT I DONT THINK SO. I'LL TRY SOME DIRECT JUMPERING TO RULE OUT THE FUSE BOX ITSELF

I think you said you already measured the voltage drop at the box with the coil disconnected? YEAH, IT ISN'T THE COIL

Could there be a fault in the ignition switch that is diverting current to something? I AM STARTING TO SUSPECT THE SWITCH SO I''LL START JUMERING AT ITS CONNECTION AND SEE WHAT I GET

I don't see how as you'd probably see evidence of this in something else coming on our shorting out? What happens if you jump the black wire to the pink at the ig switch connector block bypassing the switch?

This is a tough one.[/quote]

YES, VERY. I WAS A NAVY ELECTRICIAN AND I'M NO ROOKIE AT AUTO ELECTRICALAND THIS ONE HASME BAFFLED. I MAY JUST DISCONNECT EVERYTHING I CAN FIND AND ADD IT ALL BACK ONE AT A TIME.

[zachmac]

Update and possible progress:

I disconnected the ignition switch at C31 and did several tests.

Jumpering the brown to the lt blue/blk did not causea drop in voltage. Nor did a jump of brown to red AND it did indeed cranke the engine. (Wow are these cars easy to steal or what, two jumpers and a short connect at an easily reached plug. When this is all over I'll have to remember to install a secret cut off!)

Jumpering the black feed from F9 to pink causes the drop. This occures with or without the coil wire connected AND with or without the pink wire to F1 connected on the hot side of the fuse box. I get the exact same results with a direct jump of battery volts from the black feed to F10 to the pink wire at C31 bypassing the fuse box so I think that rules out the fuse box high resistance that shows up under load theroy as well as ruling out the ignitions switch itself.

BTW, the ignition switck also tests postivie as per the diagrams and shows no gounds. [As a side note the first drawing (A or 1 depending on your version) of Bradleys excellent wiring diagrams has an error on the ignition switch in that it shows the brown ignition lead connecting to a blue / red wire to F2 which is of course actaully fed by the lt blue/black ignition wire. He has it correct on other pages.]

So, I think I have narrowed the fault down to the hot side circuit the pink wire feedsat F1. That brings me back to the mistery green / black wire that also comes off of that feed to the fuse box. it doesn't appear on any drawings I have and I don't know where it goes! A reading of that lead to ground, disconnected from the fuse box shows a little less than 500 ohms. I think somewhere on that circuit is the problem?

[jimincalif]

Does sound like progress.

I looked behind my fuse box, I don't see a green/black on F1 (the most inboard). Although you must be a lot more flexible than I am, getting under there to look is not easy.

You're more the trained electrician, but isn't 500 ohms is a bit high to drag down the voltage that much? A starter motor is nearly a dead short but you'll still seem more more volts when it is cranking than you're seeing when black connects to pink. The runs aren't long enough to drop the voltage that much unless there was so much current something would melt.

[zachmac]

Does sound like progress.

I looked behind my fuse box, I don't see a green/black on F1 (the most inboard). Although you must be a lot more flexible than I am, getting under there to look is not easy.

You're more the trained electrician, but isn't 500 ohms is a bit high to drag down the voltage that much? A starter motor is nearly a dead short but you'll still seem more more volts when it is cranking than you're seeing when black connects to pink. The runs aren't long enough to drop the voltage that much unless there was so much current something would melt.

Yeah, 500 ohs is not like a dead short or anything. Strange that with the brown jumpered to blue at C31 I have power to F2 but the horn still doesn't work? If I push the button power drops to squat (as you would expect) but the horns don't work. A hot wire to the yellow wire under the hood to the horns results in a loud blast. Maybe a ground of problem in the column switch mechanism? A LOT passes through there. I'l be tearing into that next.

[jimincalif]

looks to me like the horn feeds off F10, violet? Not F2? And it is coming off the fused side of the box, and you've already found the voltage drop even with all fuses out, so I don't know that this is related. Still seems to me the issue is related to the pink wires somewhere since when you connect black to pink, either jumpered or thru the ign sw, you lose your volts.

[jimincalif]

If you put the meter on the pink wire at C31, what resistance do you get?

[zachmac]

Nope, it was the lead from the alternator feeding F10. With both ends loose it tests infinite to ground but sure enough, it has a high resistance under load. I just jumpered from the spare power lead on on the brown wire C17 connector to the F10 feed connecting and damned if everything doesn't work fine. Car strarted right up and runs like a champ! Sorry no beers as I nuked it out but thanks to everyone, especially Jimincalif for talking me down from the cliff. Jim, I assume you are in CA but if you are ever in SC or I am there I still owe you a brew or two!

Whew!!!! Off to the store to buy heavy gauge qwire and connectors. I am going to feed F10 with a new wire form the starter post! I could use the spare lead on C17 but I don't want to overpower the brown wires!

[jimincalif]

Congratulations! No beers needed, you did all the work. But go back and check out the 3rd message in this thread!

I'd look for a fault in the wire running from the alternator to L10.

[zachmac]

Congratulations! No beers needed, you did all the work. But go back and check out the 3rd message in this thread!

I'd look for a fault in the wire running from the alternator to L10.

Jim,

You are correct, I do owe you in that if I had followed your advice then I could have saved myself a lot of frustration and needless trouble shooting. I made the wrong assumption that if I had battery volts at the fuse box that lead was good. What I missed was what the double red wire off F9 and switching the ignition on have in common: either puts a load on the system. The red wires powerthe clock and the ignition powers the coil. That is why EITHER caused the drop. I wrongly assumed they must share a circuit and that circuit must have a ground fault. It wasn't until I tried powering something I new worked directly from the feed to F10 that the light (in my head) clicked on.

I am a man of my word. What do you drink? I'll paypal you the price of a case or bottle.

[jimincalif]

No worries Jeff, really, just teasing you. If I'm of help to anyone here hopefully I will be able to draw on that karma when I have a real puzzler with my car. I don't drink enough anyway, still have most of a six pack left I bought last Sept!

[zachmac]

No worries Jeff, really, just teasing you. If I'm of help to anyone here hopefully I will be able to draw on that karma when I have a real puzzler with my car. I don't drink enough anyway, still have most of a six pack left I bought last Sept!

Jim,

That's cool. I'm actully the same way, if you leave a six pack in my fridge and come back six months later there is a good chance you'lll find it there waiting for you. Now if you leave behind a nice bottle of red wine you'll most likely get a very different result.

I think the lesson on this one is don't overlook the obvious. In hindsight a high resistance feed is the only answer that fit all the symptoms. Hopefully I'll be able to pay it forward at some point.

BTW, this could be the real source of many of the similar problems I've read when searching for related posts. This going along then wham dead is exactly what I expereinced a few times before it got bad enough to quit for good. I'll repost just the solution in case others got tired of following what truned out to be an unnessesarily long thread.