I posted in The Bench about this, but I figure it couldn't hurt to ask here as well. I have a short somewhere. Currenlty, I have no current :laugh: . I have no interior lights, no headlights, nothing, nada. I went to start the car the other day and heard a pop and then everything went dead. I have no power coming out of the BAT terminal on the fuse block. I disconnected the main harness at the firewall and tested the big red and purple wires. Both have 12V, but I'm not sure if the purple is supposed to have 12V. The purple wire is the wire connected to the S post on the solenoid. In an off state, should the S post have 12V or 0V. If the answer is 0V, then my solenoid must have shorted out. If the answer is 12V, then my next guess is the neutral safety switch or the ignition switch.
when you turn the ignition switch to "start" it shoots 12 volts through the purple wire to energize the S terminal on the solenoid and cause the motor to crank over. in a car with points.... the solenoid not only makes the starter spin and engage but also connects the "I" terminal (yellow wire) to the fat battery cable shooting 12 volts directly (un-ballasted) to the coil to help the car start. so your answer is ... the purple wire should NOT have 12 present except while cranking the motor over. but the nuetral saftey switch should not affect the headlights. to me it alomost sounds like you purple wire and red wire are melted/mashed together under the hood somewhere. but that still dont explain the lack of juice at the fusebox. uzzled: has you engine compartment suffered any trauma lately ...like a transmission change? or burned wires?new exhaust?
Thanks Yuk, that is what I needed to know. If it is the solenoid that is shorted, that would make sense, I think, why I have no headlights, etc. The first place the battery cable goes is to the solenoid, so if its shorted, 12V would never make it past it to power anything else. If I have it correct, the circuit would be + post on battery, to bat post on solenoid shorted to the S post and the S post is grounded. Probably just have to replace the solenoid I should be good to go.
i think that the starter would be cranking all of the time if the purple wire was shorted. if the nuetral switch was grounding out the purple wire should burn in two. i will be surprised if replacing the solenoid fixes it ... but it might be step in the right direction and its a rather inexpensive and good place to start(no pun intended) :laugh:
That makes sense, too, that the starter would be going. I had the starter disconnected, though, from all the interior wiring when I tested that wire, having the main harness unplugged and testing from there. Could it be possible that the starter and or solenoid burnt out and shorted out at once? Good thing its supposed to be in the low 50's and sunny tommorrow. Just going to jack her up and take a look at the starter and see what is going on down there.
that is possible, but i think there is more to it than that..... when you unplugged the bulkhead connector from the firewall. there should have been TWO red wires that tested 12 volts. one would be a 10 gauge that pretty much runs the car, and the other would be a 12 gauge that does the headlights (and taillights i think). did both reds have voltage? have you converted this car to an HEI distributor? if so, how was it accomplished? do you have a GM wiring schematic for your car?
I did test both the red leads, I forget if the 12 gauge had voltage, I know the 10 gauge did. I have a Ignitionman, HEI converted distributor and I wired it using a new wire from the bulkhead connector to the coil. I taped off and folded back the white/orange/purple wire. I should probably check that, too. Hopefully I will solve this tomorrow once the car is jacked up and I can put the meter directory on the solenoid posts. And, yes, I do have the color wiring schematic as printed in my '73 Chassis Manual.
usually the 12 gauge is exclusively headlight juice. the parking/taillights get juice from the 10 gauge after it runs through the fusebox. keep us posted.
Zack, Hook the starter back up, and then test at the bulkhead connector at the Firewall. Both Red wires have to be hot.. Best to use a test light instead of a voltmeter, as backfeeds with very little amperage capablity can fool you with a meter. I am willing to bet you popped one of the fuselinks at the starter. They are located aproximately 1 inch back in the red wires (there should be two of them) down by the starter. Fuselinks do fail just because of age. If you find a bad fuselink, disconnect the batt, replace the fuselink (available at parts store) and then turn everything off in the car, close the doors, and then just momentarily touch the batt cable to the batt post.. you should see no spark.. if you get a spark (especially a big one) then you may have a short somewhere that you will have to locate. Good luck JW
Fixed!! Okay, so I first test the main harness again and I have 12V and both the red wires and 0V at the purple. Next, I jack up the car and take a look underneath. Ofcourse, being a 33 year old daily driver, never opened, its nice and greasy down there. So, I'm on my back, looking up at the wires and what do I see? Both the fusible link wires are intact, but about a half inch above the fusible collars, on both wires, is an inch and a half of bare copper. I don't what was supposed to be there, maybe tape that fell off or something. So between them being right next to each other and all the grease covering them, it must have been shorting there. I made sure by removing the wires, which required removing the starter to get to the wires, and unbolting and pulling out the lond cable holder thing. Then I hooked back up the wires and used jumper cables to ground the starter to the car and turned the key. BINGO! Interior lights, starter spinning. So I take electrical tape, individually wrap the bare coppper up, put everything back together and she started right up. I know I probably should have gone and put in new links, but it was late, cold, no soldering iron handy, etc.
bad link jim beat me to it :Comp: the problem with fuseable links is they can partially burn up,have a couple strands hangin on,pass voltage but not any amperage load.also the solenoid being bad wouldnt affect the lights,as the terminal is merely a junction point to take a tap for power.if the solenoid is "shorted"(wire to wire connection)you wouldnt know until you engaged the starter."grounded"(pos connection to ground)would burn the link or let the smoke out of your cable uzzled: replace the link for $5.00 first,or bypass it with jumper cable,just be aware if something IS grounded,pull it off quick,then go find that problem ou:
did you find any bare spots on the purple wire? broken fuse links alone would not make voltage show up in the purple wire. sometimes all the years and heat get to the jacket on the fuse links and it can shrink and/or chip away once it gets brittle. i like replacing the fuse links and at the same time move all of those wires (both reds, the purple, ignition wire (if present) and the main battery cable) up and away from all of that nasty heat. using a jumper (made from a small piece of heavy sheet metal with 2 holes drilled in it) at the starter and install a ford type solenoid on the fender or frame. every car i have ever done this on never had hot start/crank or fuselink problem again. plus if you ever have to change the starter, there is no voltage at the starter. you can disconnect its only power cable from the ford solenoid ... it makes alot more sense than the way GM did it. :Smarty:
