Okay, so I think I know the answer to this, but will ask anyway... This old starter took a dump on my '66 Chevy 250 in my '64 Chevy C10. I lost all power inside and elsewhere... All 3 wires were hot with 12v on the solenoid with the key out of the ignition. I pulled it tested it again, same thing... I had continuity between all three posts... No bueno. Fast forward to today, I fixed the wiring harness (wiring was bare from the hot small post on the solenoid to the coil and fuse box... and shorting against the block and cab). I replaced the wire and that was all I needed. I hooked the battery up and ran the hot down to the main battery post on the starter, but did not have any voltage to either smaller post (I thought I was supposed to just have one that is hot. If the wiring is shorting elsewhere from the normally hot post on the battery, wouldn't I still show some voltage on that post? Also, I used alligator clips and jumped to the hot lead of the starter and got the oil pressure light on in the cab (key out of the ignition), but no head lights, etc. and I didn't have anything else... So long story short, everything was working great then all of a sudden I lost power...I replaced the starter and fixed the wire... now I can't get power back at all. I don't understand it. Is the starter solenoid bad? what else could it be? I am pretty sure the solenoid is bad if I am not showing any hot lead to that small post. Thanks for the help!
After 65 gm put the ignition circuit in the key that stayed on in start. Prior to that there was another wire from the starter r terminal to the coil. At that same spot, on the coil, the old resistor wire or ballast wire attached. Giving voltage while cranking from the starters solenoid. They kept thst practice up til the early 70's to give the coil while cranking, full voltage instead of resisted while running. When you jumped the solenoids terminals you sent power up the wire to the ign switch, back feeding it.
Key off, check power to the key. Key in on, check power to the coil. Key in start, power to s terminal on starter, should crank. While cranking, if it dont start, assuming fuel and such is good, check the coil + for volts.
power to the key = 0 V, key on and start power to the s terminal = 0 V, key on and start power to the coil = 0 V, key on and start I do not have any power leaving the main battery cable connection on the starter. If I jumped the power from the main terminal to the small hot post (not the starter post), wouldn't I technically be able to run everything else? I have done this, but got some weird crap going on in the dash. Isn't this 250 supposed to have a ballast resistor? I didn't see one on the firewall... or at least don't remember seeing one.
Your main power wire is missing or open. There should be a large gauge wire that runs from your battery to the fuse panel/headlight switch and to the ign switch. It maybe attached to the main batt stud on the starter. It also goes to the amp gauge.
The post is not getting power at the starter. I think this explains it but when I jumped to that post from the battery cable post the oil pressure light came on without the key being in... That is where I am getting hung up. It is doing something strange that it hasnt done before
You should have a heavy (10ga? 12ga?) wire from the battery terminal to the horn relay, then everything else gets power from the horn relay. At least that's how all the 60's GM stuff I've worked on is wired.
The best advise I can give is to hunt down a factory 64 C-10 shop manual Not the Haynes or Chilton but a real General motors 64 Chevy pickup shop manual with the info in it. Here is a basic wiring diagram that should be close to what the 64 has. What you did was fry a bunch of wires and now one by one you have to replace/repair the wires that burned. His shot is better than mine http://s398.photobucket.com/user/li...cal/ChevyC101965-EngineHarness-COLOR.jpg.html Very old thread but click on post 4 http://67-72chevytrucks.com/vboard/showthread.php?t=308536 When you fried the wires you also fried the wire that runs power inside the cab. You can see the red wire that runs across from the battery to the Horn relay. If you follow that wire as it continues on it runs power to the fuse block and then to the ignition switch. Follow that (red on the page) wire across the core support to the horn relay and take your 12V test light and check for power there. If you have power there go to the next stop at the regulator and then on through the connector plug in the firewall to the inside and on up to the back of the switch were the wire should be hot all the time. The problem with these old trucks is that many have had 50 years of half assed bandaid repairs to the wiring and many have cut and splice jobs on the wiring for one reason or another and usually one of those is what shorts out and burns the whole wiring up. Do you have 12.5 or so volts across the battery posts? Then do you have 12.5 volts where the + battery cable bolts on the solenoid? Remember you have to have the battery grounded to complete a circuit and you have to have a good ground on the test light or instrument. I always test my test light across the top of a battery when I go to use it as I've had more than one that didn't work right or didn't work at all. You won't get power from the battery terminal on the solenoid to either of the other posts S Or R/I depending on the markings it doesn't work that way. Ebay item number for 64 truck shop manual 150902228314 About 23 bucks with expedited shipping
Killer information, this is what I was looking for, thank you very much. I swear I have a manual in my stack that covers most, if not all, of this truck specifically, I spent 3 hours going through half of them and didn't find what I needed. I guess I am going to have to toss some clams in for the year specific manual. I always check my grounds first, I learned that lesson the hard way a long time ago at an early age. I am fully grounded from battery to block, block to frame, there isn't an issue there. I have 12.5V on the battery and to the post on the starter. As I walked to work this morning I took a look at the horn relay wiring from the battery and it looks like there is a bad repair on it, so I will look into it after work. It looks like another case where they twisted wires together, balled them up, and taped them. I will check this tonight. Thanks again!
thanks again for all of the help guys, I used this wiring diagram that you supplied and found my problem. I checked the horn relay and voltage regulator and was getting power to the firewall... The firewall plug was connected and had never been separated.. I removed it made sure all of the spades in both plugs were good and tight, sprayed it out with electrical terminal cleaner, plugged it back in... bingo... that fixed it.. I wiggled all of those wires before and nothing happened.. took it apart, put it together, and it worked, go figure. It fired up and ran like a champ... better than before... and I was able to tune the carb in and get it to idle correctly.
Great to hear you had success.From the above posts you had some great advice,and I actually learned a thing or two along the way as well.
Cool. I've seen too many of those plugs with burnt terminals in them over the years. Glad to see that you got it working.
Hello my 65 C10 just started to have starting issues with no crank. Will start if you jumped the started solenoid. While looking at your diagram I noticed a red and yellow wires connected to 1 post on the solenoid. Looking at my starter solenoid I noticed a wire dangling. How can I test this wire to see if it’s supposed to be on the solenoid? Sent from my iPhone using Tapatalk
If you look at the top of the wiring diagram I posted in post 10 in 2013 you will see the 16 gauge purple wire. That is the purple wire that you have hanging down. If you look up in the plastic cover a few inches it should be purple and is your purple 16 gauge start wire that goes to the S post on your solenoid. I'd think that you have a terminal with a broken wire on that post.
Hello I just check and there’s a purple wire already attached and the dangling wire is also purple. Maybe the previous owner wired a new wire? Btw the dangling wire is in the same loom as the yellow and the yellow is there by itself. Sent from my iPhone using Tapatalk
That could well be. Probably the replace a wire thing because the connection crapped out at the firewall connector. It could be that the wire that is connected to it is the original wire and the other was there for another reason. I'd track the wire back though the harness and the plug all the way to the switch. One thought, if it is an automatic check your neutral safety switch. If the truck is new to you and you have never run it check for a push button that is there in place of the neutral switch. A good test light is going to be your friend here. It might also be productive to start at the ignition switch and work out. Meaning find out if there is power to the start terminal on the switch when you turn the key to start, then work outward tracking the wire to the firewall plug and then on the other side.
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