I am still trying to track down the short in my wiring harness. It does not seem to be anything in the engine bay or on the engine harness. It's when I plug the 'engine harness' into the fuse box that I have problems, specifically with the battery/hot wire with one of the fuseable links (not the one for the alternator). So, I have a short on the 'dash' side harness.

I systematically pulled each fuse and wire out of the fuse box and tested my engine side hot wire. still grounded every time.

It seems to me that I need to trace ALL of the wires that get power from this wire (with ignition off) to find the short. I priced a new 'dash' harness for $458 from M&H wiring, but I really don't want to have to rewire the whole inside of the car (plus stereo). Not even sure a new harness would fix the problem necessarily. Seems like I have a short from a wire wearing through the insulation as the car was working one day, then the next it blue the fuseable link.

Is there a way to check an individual wire for a short without having power hooked up to it? I have a voltmeter, just not so good at using it yet.

Thanks for any help/suggestions.

 

Go to one of the big electrical stores like a Graybar or Summers electric supply. Get a gizmo called a Fox and Hound. Its a signal box and a sniffer, you can use it to trace the ground fault with that

 

You need to disconnect the battery. Then make you up a long (10-12 feet) continuity checking line to hook up to your Ohmeter. Buy 12 feet of lamp cord at Lowe's (12 or 14 gauge). Separate most of the lamp cord into two individual lines; leave it connected for a few inches at the meter (for convenience). Put alligator clips on the outer end of the wire. When you determine what wires you need to "chase", just disconnect each piece of that string and hook your wiring to each end of the line being checked. Set the meter on Ohms scale (10 ohms, for instance). You are looking to see that the wire shows connection from one end to the other (the wiring should not be connected to any components). Then, remove the clip from one end of the wire and re-connect it to chassis ground [engine, frame, or a terminal lug with a black wire connected. If that wire is shorted, the needle will swing to "0" ohms reading. If so find the short and fix it.

 

So your saying when you remove all the fuses it still goes to ground.That wire only goes 4 places other than the fuse box.Headlight switch,horn relay and batt.2 and batt.3 term. on the ignition switch.Unplug those 4 items one at a time and see if that narrows it more.If that doesnt do it open the bulkhead connector.

 

This may be a shot in the dark but..... I have seen the ground wire that is suppose to be attached to one of the passenger side bell housing bolts inadvertantly connected to the positive pole of the starter.

 

Good thought I just checked his previous thread and he said he has 5 wires going to the starter.

 

Thanks a lot for the help guys! I did order a better wiring diagram off of ebay last night as well, hopefully that will help.

LT1vette: Thanks a lot for the continuity check directions. What kind of Ohm reading will I have with the clips hooked to each end of the wire I am checking?

DW: I have yet to disconnect the ignition switch wires. It could be one is shorting somewhere. Could the ignition switch itself go bad and cause this? How do I get the switch out? I took the stearing column support bolts out and dropped it an inch or so, can see the ignition switch and wires I think (on the column not inside right?).

I had the car running the day before I did this and nothing was changed, so the starter is not the issue. I also redid the starter wires anyway, just to be sure last weekend. The chassis ground is h ooked to the body of the starter.

 

When you say chassis ground do you mean the large battery cable type up by the right motor mount?The wire vetteman was talking about is the ground for your wiper and blower motor-its a Black 14 gage wire(small)but has a connector on it "large" enough to go on the large terminal of the solenoid with the battery cable. ??? Check it -it is a common mistake.If it is on there the case of your wiper will be hot which will create a short.
I would just unplug-to check the ignition switch its a bitch to get them out and back in.Even the connectors are tough to get off.

 

I also have the 14 gauge wire grounded on the case of the starter. I'm pretty sure I have the starter wired correctly as I have had it out about 10 times in the last couple of years due to some timing/starter/ringgear issues I had a couple of years ago. Remember, I did have the car starting and running the day before this started.

Hot side of the starter has the battery cable, stock hot wire, MSD ignition box wire, efi hot wire on it.

OK, ill try the unplug' routine tomorrow and thanks.

 

OK, I found the short (finally). I disassembled the entire dash, dropped the steering column, disassembled the fusebox and dash harness and started checking the batt/power wires. I also ordered a nice wiring diagram for a '76 for $20. That diagram alone made this so much easier. The diagrams in the Hays manual I have are basically worthless, not to mention that there is not a '76 diagram in the book (all years except '76). '76 must have some unique things on the harness for some reason.

Anyway, it was the horn relay/power wire shorting out. Apparently when I put the hood on and put some foam down behind the radiator to protect the nose of the hood, I pressed the horn wires, which were not in good shape anyway, into the frame/vacuum cannister/bumper tube.

Pretty depressing looking at the state of my interior now. I did put a new tach board in the tach/dash while I had it apart, hope it works. I'll be able to wire up my FAST XFI EFI system soon, maybe Monday. I bought a fuse block and plan to mount it in the small/middle compartment behind the seats to run my battery power wires down the tunnel under the console, for the fuel pump/MSD 6A box/FAST XFI harness. Power from the positive battery cable auxiliary wire (8 gauge?) should power this up just fine shouldn't it?