Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Sign in using an external account
Register Forgot Password?
Register Search Today's Posts Mark Forums Read FAQ Vendor Directory
Search
C4 Tech/Performance
L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine Sponsored by
J&D Corvette

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C7 Parts & Accessories
C6 Parts & Accessories
C5 Parts & Accessories
C4 Parts & Accessories
C3 Parts & Accessories
C2 Parts & Accessories
C1 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 11-15-2007, 05:07 PM   #1
platergd
CF Senior Member
 
platergd's Avatar
 
Member Since: Nov 2006
Location: Waldorf Maryland
Default Lead red wire to alternator hot

I have been trying to trouble shoot why the lead red wire on my 91 corvette alternator has been getting hot enough to melt the plastic wire harness around it. I have had the alternator checked and it was ok. I unpluged just about all of the fuses leaving just enough to keep the car running and it still gets hot. Could it be the voltage regulator in the alternator? My voltage regulator needle runs close to 18 volts even with the AC and lights on but has never gone in the red. Has anybody else had this problem? I can't figure this one out. Where does that red wire lead to?
platergd is offline   Reply With Quote
Old 11-15-2007, 06:10 PM   #2
REDC4CORVETTE
CF Senior Member
 
REDC4CORVETTE's Avatar
 
Member Since: Apr 2004
Location: Lahaina Hi
Default

May be a starter problem?
That wire should go to a relay behind the battery.
Someone may have tied something into the wire pulling it to ground.
If it went to ground that would make the voltage go up and get the wire hot.
__________________
Johnny Carson once said.A married man may live longer ,but is more willing to die.
REDC4CORVETTE is offline   Reply With Quote
Old 11-15-2007, 06:52 PM   #3
CFI-EFI
CF Senior Member
 
CFI-EFI's Avatar
 
Member Since: Sep 2000
Location: The Top of Utah
Default

Quote:
Originally Posted by platergd
My voltage regulator needle runs close to 18 volts even with the AC and lights on but has never gone in the red.
If 18 volts isn't in the red, it ought to be. I consider 15 volts to be marginally too high. BOTH red wires to the alternator are direct battery feeds through fusible links. One is the output generated by the alternator, and the other feeds the regulator. It does sound like a regulator problem. Unless there is a short in it, it isn't likely to be anything to do with the starter. And if it were starter related, it would have drained the battery before you tried to start it.

RACE ON!!!
CFI-EFI is offline   Reply With Quote
Old 11-15-2007, 09:48 PM   #4
jfb
CF Senior Member
 
Member Since: Mar 2001
Location: Cincinnati, Oh USA
Default

The reason why your red alternator wire gets so hot is because at 18 volts, your alternator is charging the battery near its maximum rated current, or about 130 amps. The voltage regulator in your alternator is DEFECTIVE !!!!!!!!!!!!!!!!! Either replace the voltage regulator, or replace the entire alternator! GM says maximum alternator voltage must not exceed 16 volts. And if my alternator put out 16 volts, I would replace the voltage regulator. Normal alternator output is 14.7 volts cold and this drops to 13.7 volts hot.
jfb is offline   Reply With Quote
Old 11-15-2007, 11:47 PM   #5
Sam Lam
CF Senior Member
 
Sam Lam's Avatar
 
Member Since: Apr 2002
Location: St. Charles, MO Route 66 Corvette Club
Default

Holy schmidt......18 volts is EXCESSIVE for a 12 volt system car. with the above two posts. I would question the compentance of the person who tested the alternator.
Sam Lam is offline   Reply With Quote
Old 11-16-2007, 02:18 AM   #6
platergd
CF Senior Member
 
platergd's Avatar
 
Member Since: Nov 2006
Location: Waldorf Maryland
Default Lead red wire to alternator hot

Thanks. One more thing if this is any help. The the red wire starts to get hot at the alternator lead first and radiates back down the wire"?". I unplugged all the fuses and turned on the headlights and instantly the wire got hot with no effect on the voltage meter which was close to 18 volts.
I'm going to buy a new alternator. It will be a costly mistake if it is something else. Comments if anyone has any.

Last edited by platergd; 11-16-2007 at 08:20 AM.
platergd is offline   Reply With Quote
Old 11-16-2007, 07:18 AM   #7
kalister1
CF Senior Member
 
kalister1's Avatar
 
Member Since: Sep 2005
Location: Pasadena Maryland
Default

If you want to be sure(everybody else already is). Put a meter on the wire at the alternator and measure the voltage there. If you don't have one, you can get one for less than $20.00. I have never seen anything more than 15 volts, mine runs at 14.5 MAX!
kalister1 is offline   Reply With Quote
Old 11-16-2007, 10:20 AM   #8
platergd
CF Senior Member
 
platergd's Avatar
 
Member Since: Nov 2006
Location: Waldorf Maryland
Default Lead red wire to alternator hot

Well, back to the drawing board. I brought a new alterantor and the red wire is still getting hot. When I disconnect everything, The wire still get warn but not as fast as when I put all the fuses in. Could this be a major ground or something as simple as the stereo grounding out "?".
platergd is offline   Reply With Quote
Old 11-16-2007, 10:38 AM   #9
jfb
CF Senior Member
 
Member Since: Mar 2001
Location: Cincinnati, Oh USA
Default

For some reason you have a large current load on your electrical system and the alternator supplies current when the engine is running. One thing you should check is the condition of your battery. Everything off, measure the voltage across the battery terminals. At 12.0 volts or below, the battery is considered discharged and the alternator will supply large current to charge it up. If you have a shorted cell in the battery, it will measure 10 volts and the alternator then will charge with very large current causing a hot alternator wire. But, at 10 volts, you may not be able to crank the engine. Engine off, disconnect the negative cable on the battery and connect an ammeter (at least 20 amps full scale) from the neg cable to the neg post on the battery and see what the current is ignition off then ign to run.
jfb is offline   Reply With Quote
Old 11-17-2007, 01:04 AM   #10
Sam Lam
CF Senior Member
 
Sam Lam's Avatar
 
Member Since: Apr 2002
Location: St. Charles, MO Route 66 Corvette Club
Default

You appear to have a dead short in your wiring or a problem with the battery as described above. Carefully check the red wire to make sure it has not worn its insulation off and is touching part of the frame or engine. Also, examine the wires going to your starter for shorts or grouding to the frame of the car. You may have top open some of the plastic conduit to trace the red wire.
Sam Lam is offline   Reply With Quote
Old 11-19-2007, 02:53 PM   #11
platergd
CF Senior Member
 
platergd's Avatar
 
Member Since: Nov 2006
Location: Waldorf Maryland
Default Lead red wire to alternator hot

Thanks I'll be checking all those areas.
platergd is offline   Reply With Quote
Old 11-19-2007, 02:53 PM
 
Go Back   Corvette Forum > C4 Corvettes, 1984 - 1996 > C4 Tech/Performance
Reload this Page Lead red wire to alternator hot
 
 
 
Reply

Tags
17, alternator, cable, car, corvette, drop, hot, lead, led, red, supposed, voltage, volts, wire, wires


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -4. The time now is 01:10 AM.


Emails & Password Backup

Search Engine Friendly URLs by vBSEO 3.5.2