KenSny

I removed this from my previous post in the hope that the title change would get more responses.

This all started because I needed to drop the oil pan and I removed the starter to ease that job. Everything went back together with no problems.

I go to start the car - Turn on battery disconnect and all interior lights come on - so far so good. Turn iginition key to start and all power instantly gone.

All battery connections are clean and tight, but down at the starter I do not have 12v at the battery connection.

I disconnect all wires at the soleniod and check them one-by-one. I have 12v at the battery cable. But when I measure the 2 red wires that connect to the same terminal I find "ground" - I'm thinking that's not good, as one of these is supposed to be the 12v feed to the main fuse block and the other goes to the ammeter/voltmeter. I split apart the 2 wires and see that each wire has about 6 ohms between the end and ground. So it would seem that both fusible links here are good.

It looks like the 12v fusible link at the fuse block rear is damaged but I'm not really convinced it was burned up, but it looked like it was ready to break apart, so I repaired it anyway.

I traced the large red wire from the starter connection to the buss on the fuse panel that feeds three fused circuits: #1-haz/stop, #2-tail/side lamps, #3-ctsy/ltr/clk/antitheft/glovebox

I pulled these fuses one-by-one and when removed #3 the low resistance to ground disappeared. I did not expect this since that feed is also connected to the rest of the car (the ignition switch, light switch, & horn relay). I reinstalled all but #3. I'm confused - I would think that if any of these items on the circuit are grounded the 20a fuse would have blown and it did not.

Questions:

1 - Can I assume that the engine harness (starter to fuse block) is OK?

2 - As a side issue I read 12.5v across the battery terminals. Could the battery be bad and still show good voltage since it was being "grounded" at the solenoid.

3 - I would think I should be able to start the car now if I put the starter back in and the battery is good enough to crank it over. I'll probably try this later this week.

4 - Any ideas or suggestions of where to look now would be GREATLY appreciated.

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BTW: Don't we all hate electrical problems? I'd rather work on a mechanical problem any day - at least I can see it to fix it. Who can see the magic of electrons when they are all covered up. And don't they just leak out if you strip the wire bare? That's what my 11yr old stepson wanted to know a few days ago, and at that time I thought he may be right - out of the mouths of babes - you know. Boy was I getting desperate!

sb69coupe

Ken, I will bet you $20 that you were measuring the resistance with the doors of the car open, right? That's why #3 goes to ground, the courtesy light switch grounds the 12v feed when you open the door in order to light the bulbs. Close the doors and measure the resistance again and you should get the accurate reading.

Shannon

KenSny

That came to me about 20min after scratching my head. The alarm pin switches are also on that circuit so I closed the doors and hood and made sure the glove box was closed. Same thing. Then I removed the bulbs for the interior area and the glove box. Same thing. Then I pulled the door switches and the alarm switch to remove the wires. Same thing. I'm lost now.

But even so, I should have 12v at the starter with everything connected - right? That purely stumps me.....

Gordonm

I have 12.6 at the starter on the main lug. I know it is good because I just took it for a ride this afternoon and cranked good. I would suspect your battery. When you release the key from the start position do the lights inside come back on. If so make sure your battery is good.

KenSny

Gordonm - I know, but I don't have anything, interior lights, etc. BEFORE moving the key to crank the starter (I did before all this happened). But if I disconnect at the starter then I have 12.5v.

I would think that I should get some interior "light", however dim, even if the battery was not putting out any amps since I am getting 12.5v across the terminals.

I will not have time today to pound my head against it, but tomorrow I'm going to put the starter back in, connect all the wires, and leave out the #3 fuse and see what's what. :skep:

Paul Borowski

Ken, one electrical problem I had with my '75 once was(and I bought another starter & battery BEFORE I found the problem)the MAIN FRAME ground below the battery compartment. The short black battery ground cable was "swelled up" with that "green corrosion" & it was'nt getting any current through it. I replaced it, car started INSTANTLY. BEFORE this incident, as the cable was going bad, weird things electrically were happening to me on this car, headlights dim, slow cranking starter and would drive the car, shut it off, and it would not turn over until it cooled down-almost like starter heat soak.

KenSny

Paul, I'll look at that first. I am thinking the battery may be bad now IF it was truely grounded at the beginning of this problem. I don't have the test equipment to test it under load. I may just try to swap in the battery out of my daily driver since I can't get in there to jump it (Corvette's on the wrong side of the garage and up on ramps).

Shannon - I had completely ignored that the clock is also on that circuit. So even with the bulbs out, and pin switches all disconnected I would still get some resistance....




[Modified by KenSny, 10:47 AM 9/25/2003]

72GACRZR

This isn't a case of the big black ground cable the goes under a starter bolt getting hooked back to the starter instead, is it?


Reference :
http://forums.corvetteforum.com/zerothread?id=606174


[Modified by 72GACRZR, 11:36 AM 9/25/2003]

KenSny

Henry - Nope, I'm sure about that!

RLaFarge

It really sounds to me like when the battery is loaded it loses it's current flow ability. A dead cell more or less. I have seen them not let the lights come back in a car as well before. On a different system we had a load on a battery to start and ignition sequence and then it would shift the battery over to a secondary power source for computer guidance system. We kept getting an alarm on the secondary power source. It took a while and some argument among the engineers there, but when the battery with to a high load state, it would lose is ability to act as a cap and it was dead as a hammer afterwards. I would pull it and take it down to autozone or the like and let them load test it.

What happens if you run a power lead directly to one side of the solinoid?

KenSny

RLaFarge - That's a good idea, I'm going to try that using the battery from my other car. I have a good length of "0"awg battery cable with connectors on both ends that I can use to connect a jumper from another battery to the solenoid with the original cable removed. If that works then I'll take out the Corvette's battery - another backbending job - d..mn that's awkward to get at for removal!

RLaFarge

I just pull my seat out to get to mine. I really need to bolt my seat back in one day. LOL

KenSny

Final update:

As stated earlier I found and repaired the fusible link that was melted at the rear of the fuse block and then the interior lights came on and the other circuits on that buss (3 fuses total) were operative but nothing else.

I managed to get my other car close enough to run cables to jump the battery. No change. Then I tried to run the + cable of the jumpers to the solenoid terminal. No change.

I gave up because I could not figure what else to check.

I had it loaded on a flatbed truck and taken to a shop. First thing they did was pull the battery and load test it. They found that the battery had a good reading between the + & - posts on top of the battery but there was an intermittent internal short between the side posts (which is where my cables connect) that occurred when a current load was applied. Which is why nothing changed when I jumped my other car to the battery using the top posts.

They found a short in the harness that runs from the starter to the fuse block where it goes thru one of the cable clamps near the bellhousing and repaired that and all was working again.

This experience has really frustrated me. I HATE ELECTRICAL PROBLEMS! Next time if it's not a fuse, the car just goes into the shop. No IFs, No BUTs, it's just to much aggravation otherwise.

Thanks to all those who offered suggestions....

mrvette

Ken, I have held off replying to this post series because now that you have gotten it running, you need buy a decent DVM....and follow instructions like in a Radio Shack elementary electronics manual....that DVM with clip leads and probes is the most valuable electrical/electronic tool you can have....
all you had to do was put the probes on the + and - terminal bolts of the battery and watch the voltage disappear when you cranked....
or any other fault....

you need consider electricity as a major plumbing system,...water through a pipe, and then drain system..having done it's work.....any break in the piping the they system fails.....same thing....Voltage is considered to be water pressure, and the pipe/wire diameter is the volume or current....fuses react on current, and are a safety valve for the wires/pipes......

this crap is not rocket science these days...really, us folks living in a tech society need learn the basics of electricals just to survive these days....
not to say we all have to be engineers, but I feel strongly the schools don't teach anything at all useful for the most part....kids at age 18 should be able to use a DVM as well as a computer...and turn a wrench on the basics of car maintenance...and be able to do most household repairs....including house wiring...correctly....
but unfortunately you have to learn these things on your own....

GENE

KenSny

Gene - I know you mean well - BUT:

THERE WAS NO CRANKING - no power to crank - no starter action at all. So putting a DVM across the battery would have been useless. Guess you did not bother to read my posts, let alone offer any advice., but now you come in at the end to criticize?

I have a professional Triplett DVM that has served me for over 30 years. And I have used it in the garage as well as around the house. I have it calibrated "every-now-and-then" by a relative who has the right connections. So as you might guess I'm not a teenager anymore and I'm past having any mid-life crisis.

You're right IT'S NOT ROCKET SCIENCE, but some of us are just not that savvy when it comes to finding shorts. I read a schematic VERY WELL thank you very much, but trying to find a short up in a cable harness somewhere, I think I'll leave it to someone else who does it for a living.

So if you are going to "get on my case" because I'm not as electrical minded as you, you can keep your advice to yourself. Thanks anyway.

I noticed I used DVM so before you jump on my mistake, it's pre-digital, but a good analog meter none-the-less.


[Modified by KenSny, 1:46 PM 10/1/2003]

mrvette

Ken, sorry man, don't mean to jump on your case, but the facts are the proper use of the DVM, which can require assistance from time to time..so you can read what's happening during a sequence...starting for example....
is all the importance...and yes, having that DVM on the battery terminals during cranking with ignition disabled will tell the condition of the battery.....
any conclusions to the contrary are rong.....

Lets' just agree to disagree, as I wasn't there, and so there is a communications/observations problem what wasn't apparent from my viewpoint....sorry to offend...

GENE

blunsford

Did you check the ground connection from the engine block to the chassis? That's near the oil pan.