*!*(^*# Electrical System
Thread Starter
Racer
Joined: Dec 1999
Posts: 380
Likes: 1
From: Harveys Lake Pa
*!*(^*# Electrical System
I need some help here. On my 59 I installed a completely new wiring harness, had the generator checked and verified my wiring several times. The meter was just installed after a complete overhaul/ calibration by Corvette Instruments in Florida.
When I run the engine, my ammeter moves to almost a negative peg. (approx -28 on the gauge). I have checked voltages at various places but I am unsure as to what I should be looking for. The numbers don't make sense. At the meter I get +.02 volts if I measure from the voltage regulator terminal (right side as viewed from behind) to the terminal connected to the Battery and the solenoid. If I check eah of the terminals on the ammeter to ground I get approx. 19.8 volts. I also get around 19.8 volts across the battery when running and 18.3 when I shut it down.
Sounds like I may have a bad voltage regulator, but would that explain why the meter is moving negative ????
When I run the engine, my ammeter moves to almost a negative peg. (approx -28 on the gauge). I have checked voltages at various places but I am unsure as to what I should be looking for. The numbers don't make sense. At the meter I get +.02 volts if I measure from the voltage regulator terminal (right side as viewed from behind) to the terminal connected to the Battery and the solenoid. If I check eah of the terminals on the ammeter to ground I get approx. 19.8 volts. I also get around 19.8 volts across the battery when running and 18.3 when I shut it down.
Sounds like I may have a bad voltage regulator, but would that explain why the meter is moving negative ????
Melting Slicks
Joined: Jul 2000
Posts: 2,097
Likes: 99
From: Boston MA
The factory wiring diagram in the ST-12 has the ameter wired backwards. Some other wiring diagrams for C1s also had the ammeter wiring backwards. The ammeter needle deflects the correct amount. Just goes the wrong way. Reverse the wires, and you'll be OK.
Don't know about those 18 and 19 volt readings you're getting, though. They don't sound right.
Don't know about those 18 and 19 volt readings you're getting, though. They don't sound right.
Thread Starter
Racer
Joined: Dec 1999
Posts: 380
Likes: 1
From: Harveys Lake Pa
A quick check of ST-12, the AIM and the Lectric Limited wiring diagrams all show the same installation with the battery/ solenoid wire (black) connected to the side closest to the Oil Pressure meter and the side with the red wire connected to the voltage regulator on the other side. If this is incorrect, then it is a simple thing to switch which side the wires are on.
Does anyone know what the right voltage out of the voltage regulator should be at the BATT terminal ???
Does anyone know what the right voltage out of the voltage regulator should be at the BATT terminal ???
Last edited by jafranke; Jan 3, 2005 at 01:51 PM.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
If the voltage regulator is operating properly, you should show 13.5-14.5 volts across the battery when the generator is charging (1500-2000 rpm). The 18-19 volt readings you mentioned say the regulator needs adjustment, rebuild, or replacement. 
Race Director
Joined: Nov 2000
Posts: 10,340
Likes: 664
From: Beverly Hills (Pine Ridge) Florida
Jon,
Verify that the meter is reading correctly. The battery should read approx. 12.6 V when fully charged (after it has set a while). I am surprised that the battery was reading 18.3 Volts after shut down! Check it on another vehicle's battery.
As John Z stated, the voltage reg. should not allow the charge to be any where near 19 volts!
Plasticman
Verify that the meter is reading correctly. The battery should read approx. 12.6 V when fully charged (after it has set a while). I am surprised that the battery was reading 18.3 Volts after shut down! Check it on another vehicle's battery.
As John Z stated, the voltage reg. should not allow the charge to be any where near 19 volts!
Plasticman
Thread Starter
Racer
Joined: Dec 1999
Posts: 380
Likes: 1
From: Harveys Lake Pa
Don't you hate it when someone else asked the perfect, yet obvious question.... I checked the voltmeter on my daily driver and got about 19.5 volts... a 9 volt battery comes in at 12.5. Seems the voltmeter is bad. Thanks Plasticman.
Jon
Jon
