alternator and idiot light wiring - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 5 (permalink) Old Jan 27th, 02, 10:39 PM Thread Starter
 
Join Date: Dec 2001
Posts: 21
After I put my engine in recently, I discovered that my alternator wasn't charging my battery. I used Wes Vann's excellent techref article to figure out how my internally regulated alternator was wired wrong. The alternator now keeps that battery charged. However, my generator idiot light acts opposite of how it is supposed to - i.e. when the ignition is turned to on, the light is off and when the engine is started the light comes on. This weekend I replaced my heater core(haven't had one all winter...). After reassembling it, I turned the ignition to on and tested the blower motor on all levels. After running it on high for less than a minute, I started to smell the wonderful scent of melting wiring. I turned the ignition off and disconnected the battery. Soon a lot of smoke was coming out of the top of the dash. I ended up pulling the dash out. I found that the brown-white wire from the ignition to the firewall block had completely melted. This wire meets at the firewall block with the brown wire from the gen idiot light. On the engine compartment side of the wiring, this is the brown wire that formerly went to the voltage regulator. Wes's article said to jumper this to the dark blue wire at the voltage regulator harness. The dark blue wire goes to the alternator to energize it. I have this dark blue wire connected to the terminal on the back of my alternator with the 'R' beside it. I have the terminal with the 'F' beside it jumpered to the battery post on the alternator per Wes's article. I replaced the brown-white under the dash with a temporary wire to test things out. Since I don't know very much about electronics, I switched the wires on the alternator terminals to see if that was what fried my brown-white wire. The alternator apparently wasn't energized because it wasn't charging. So I switched the wires on the terminals back. After I replaced the brown-white wire, the headlight bright idiot light now acts opposite of how it should and both turn signal indicators stay on. Does anyone have any ideas why the gen and bright lights are backwards and the turn signal lights stay on? Thanks.

------------------
Charles - The third of my kind
'66 Malibu
clarktrip3 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old Jan 27th, 02, 11:18 PM
Tech Team
Bob
 
Join Date: Jan 2001
Location: Lincoln, NE
Posts: 637
I had the same backwards-working lights for high beam and turn signals on my 68. It also effected my gas gauge, illumination lights, and even the cigg lighter. This was about 25 years ago when I was 18, but I remember it well. It happened after I had dropped the dash to replace some bulbs. Turns out that I had failed to re-connect a ground wire. It's a simple fix, after you find it. Sorry I can't remember where it was. A mechanic friend of mine fixed it in about 5 minutes.

Just for grins....Try turning on the dome light by rotating the headlight switch, then open a door, (which would also turn on the dome light). For some strange reason this would make everything on mine work normal again. I guess that by activating two switches to the same light circuit it provided enough ground to make things work right. Strange but true!

My buddies thought it was pretty funny when one of them wanted to light a ciggarette. I had to turn on the dome light and then hold the door open a few inches, (while driving).

I'm definately no electrical expert, as I'm sure you can tell after reading this. Good luck with it.

------------------
Bob Von Kaenel
70 SS 402ci TH400
Barista is offline  
post #3 of 5 (permalink) Old Jan 28th, 02, 8:47 AM
 
Join Date: Feb 2000
Posts: 7,762
"I found that the brown-white wire from the ignition to the firewall block had completely melted. This wire meets at the firewall block with the brown wire from the gen idiot light."

If the brown wire, on the alternator, is directly shorted to ground, this can occur. It shouldn't. The idiot lamp is between the brown wire and the brown/white wire. Something is wired backwards.

"I have this dark blue wire connected to the terminal on the back of my alternator with the 'R' beside it. I have the terminal with the 'F' beside it jumpered to the battery post on the alternator per Wes's article"

Dark blue is the Field terminal and White is the Relay terminal. You sure on Wes's instructions? This doesn't sound right but maybe it's me.
John_Muha is offline  
 
post #4 of 5 (permalink) Old Jan 28th, 02, 9:35 PM
Lifetime Premium Member
 
Join Date: Nov 1998
Location: Chandler, AZ, USA
Posts: 2,222
The brown\white wire that burned is a backup to the GEN light. As stated " This wire meets at the firewall block with the brown wire from the gen idiot light". If the GEN light burns out this wire will allow the alternator to keep charging. In fact on cars with optional factory gauges, the brown\white wire is the only wire connected to the #4 terminal of the regulator.

The B/W wire is a resistor wire (aprox 10 ohms) with one end connected to 12 to 15 volts you should be able to ground the other end and not pass enough current (1.2 to 1.5 amps) to burn the insulation. So how could it? I donít know yet.

What alternator do you have? The SI alternators have two connections marked 1 and 2. The external regulator alternators have terminals marked F and R. Knowing this may help.

As for the signal lights and bright light. It is possible that the brown/white wire melted through the insulation to them thus shorting them to each other and to who knows what else.
Elree Colby is offline  
post #5 of 5 (permalink) Old Jan 30th, 02, 10:12 PM Thread Starter
 
Join Date: Dec 2001
Posts: 21
Ok guys, thanks for all of the help. Not surprisingly I have 2 problems. The first was like Barista said - not good enough ground. After I read John's reply, I started rethinking everything from square one. I went to AutoZone and asked what type of alternator they had sold me. I had wanted an SI, but the guy apparently didn't hear me. And not knowing the difference in the identification by the terminals kept me from knowing the real type. So I rewired it like an externally regulated alternator should be and put on a new regulator. About the time Elree got his reply posted, I had things fixed. So my alternator is keeping my battery charged. I need to put a good ground on now to make the lights behave. But that "should" be easy..........

------------------
Charles - The third of my kind
'66 Malibu

[This message has been edited by clarktrip3 (edited 01-30-2002).]
clarktrip3 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 6504 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome