Karp

Hi guys,
First I have read many of the forums without finding the info I seek. So thank you all for your help in advance. I own a 90 c4, while learning time adjust the rocker arms (passenger side=note fun) I over tightened the BATT cable on the alternator cracking the plastic washer. I backed it off and thought it might be okay. I started the car and drove it about 3 miles and noticed the voltage was low, the car was losing power I lucky got it into a parking lot before it cut off. I tried to restart it not fully thinking about the last few hours. The ABS light is on and she starts yet you can see its not charging. I used a multimeter to check the voltage at the battery and the four wire plug. It has voltage yet the BATT terminal show nothing from ground to it. Okay so I blew a fuse? Nope a fusable link behind the battery? Nope. Next I try and follow the wire, I lose it as it enters the wire loom at the back of the engine and top of the transmission. Can anyone tell me where that wire goes and if/where there is another fusable link or did I fry something worse? I know the wire does not go to the battery area. I check all those and theven links are not blown there. Thank you again for any advice.
Karp
90 C4 Convertible, Competition Yellow with optional Yellow Hard Top

WVZR-1

It sounds as if you've broken the stud (BAT terminal). Here's a CS130 service manual and there's a link on page 1 for parts exploded view.

https://alternatorparts.com/cs130-sbpage1.html

BAT terminal in parts link.

There's many other disassembly/assembly guides, replacement parts and service guides available on the Internet. CS130 is very straight forward. A DIY in most cases. Part should be "local" and maybe just ask a local shop to check yours and consider brushes, bearings etc. maybe dependent on miles. If it's original fix/repair yours. Replacing would be a last resort. You shouldn't need!

Joe C

- in addition to WVZR-1 link, another source for parts -- http://www.aspwholesale.com/index.php

I have done business with these folks - decent parts, decent price...

Karp

Thank you all for your input. Unfortunately I get the exact same reading with a new alternator. I think I fried something in the car. I found alot of diagrams for the C3 that said the alternator wire is tied to horn relay. So far no luck on the C4. There must be a fusable link or worse something fried.

Guro305

I maybe able to help you with this since I had a similar problem. Some will scoff at this but oh well.....old school is old school and it worked for me.

At the time I had been injured and just couldn't get under the car to do any kind of real investigation nor did I have the time. Now before I we go forward, is anything at all smoking inside your car? Anything at all? Are you seeing or at least smelling anything that smells like cooking plastic or seeing smoke coming out of your dash vents? Assuming you are not that means the Sensing wire which is usually brown if I'm not mistaken is not damaged in anyway. Now you can clip the red wire and loop it back to the BAT terminal and tighten it down with the from the BAT terminal. You can run a wire from the BAT terminal directly to the Positive side of the battery.

This is "old school" as the days of one-wire alternator. Chevy in the C4 run all the Alternator leads to the Starter and from the Starter back inside the car. It's possible you fried or shorted out the Starter and that's why it's not charging but directly connected to the battery it should give you the result you are looking for. It's not a permanent solution for alot of people but it will work forever if you want or at least to keep you on the road. You can do some Google searches for one-wire alternators and get many diagrams as to how to do it.

Here is one: http://www.jalopyjournal.com/forum/a...g-gif.1011401/

Churchkey

Suggest a visit to a starter alternator rebuilding shop let them replace the bad insulator & test the unit.

Red alt "BAT" wire: It should have 12V @ all times (battery connected).

+ battery cable feeds the power distribution block behind the battery.
Power distribution block: A red wire directly feeds the alt "BAT" terminal through a fuseable link.
If the alt "BAT" stud has been grounded the fuseable link is blown.

Remove the battery for access to the distribution block located behind the battery you will see the fuseable links.

Multimeter testing a fuseable link: Do not probe or pierce the fuseable links.

After the insulated wire coupler connecting common wire to a fuseable link back up the common wire with a small piece of wood & pierce the wire with a straight pin or hat pin,
leave it in the wire. Multimeter to ohms check for a reading distribution block to hat pin.

If you get a reading that fuseable link is ok. No reading = failed fuseable link.
Suggest checking all fuseable links attached to the distribution block the "S" terminal on the alternator is also connected to the distribution block with a fuseable link.

After hat pin wire piercing a dab of silicone will seal the insulation.

Good luck.

WVZR-1

Your '90 charging system:




Anyone who would like can reference from this. OP - you mentioned breaking and that would have hinted the BAT TERM/STUD, like "Churchkey" mentioned if you grounded that with the wrench while "wrenching" you've fusible link issues likely.

I'd say "Joe C" and I were correct with what you've busted but you hadn't mentioned attempting a FIX at that point! The buy of an alternator I'd say overkill.

Karp

Okay thanks for the tips especially about the rtv. I tested all the links behind the battery, I jacked the car up and found one there the was good. I even swapped alternatorso with a known good.


The red wire has a visible link. Tested good.




Wires one left good with voltage, the large single wire on left still nada.

If I hook up the black connection and start the car I have no output on the post. With either alternator or the wire attached or not. Maybe floats with 0.3-0.4 vdc?

Churchkey

One more time.

The single red wire connected to the stud on the alt should read 12v at all times weather the ign key is on or off. No 12v @ the alt stud = that wire is broken or the fuseable link is melted = open circuit.

That red wire is connected from the alt stud directly to the power distribution block behind the battery.

If no 12v at the alt stud you have 2 options:
Find the failed fuseable link & replace it or run a new wire from the alt stud to the
distribution block. Suggest 8ga wire & solder the eyelet connectors.

If the alt is good the charging system will work.

Karp

Hi thanks to all after all your help and after tons of trial and error. I started taking apart the wiring harness. Low and behold I find a 8 Guage connection that was melted apart. I couldn'thave done ito with out ya'll. Especially church's patience. Thank




Darn it was right there under the loom




It just melted away, when it arched.

Churchkey

Glad its fixed, good job.

Karenldm

ChurchKey, are you still out there? This is exactly the wire I need to replace, but I don't know how to do it! Wondering if anyone has a video for guidance as I am a novice.

I have a 1986 Corvette and the red wire from the alternator to the terminal behind the battery fried and severed! I've been told it's not a very difficult job, but I do not know what gauge wire to use, where to buy it or anything about the fusible link.

If you or anyone out there sees this, any guidance would be greatly appreciated!!



Thank you!
-Karen