Which voltage regulator? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jhow66 · 01-24-2006, 12:20 AM

Had to change the voltage regulator on my '65 GMC (.060 over 350) as it cooked my battery. Are there different ones for idiot lights and amp gauges? Charges fine now but the idiot light does not work with new regulator-light does not come on when you turn the switch on.(light is ok as I hooked the old reg. back to harness and grounded the reg. and it works as it is supposed to).

**VetteVet** · 01-24-2006, 02:50 AM

Just some thoughts on this. I am curious if the resistance on the new regulator might be be too high to light the idiot light with the key on and engine off or any other non charge state. I would measure the ohms between the brown terminal and the regulator ground and compare that with the old one. I believe that the points are closed on that electromagnet and when the key is on(engine off) or the alternator isn't putting out volts the brown wire grounds through that and lights the charging light and when the engine starts the brown wire feeds the alternator field and the alternator output will open the regulator points and turn off the light. Anyways measure the resistance on the terminals to ground and compare them with the old one. There may be a difference between the years.
If the old one was overcharging then the points may have stuck on it and it wouldn't be an accurate comparison. Does the light come on with the harness plug disconnected?

**VetteVet** · 01-24-2006, 03:50 AM

I just looked in my Motors manual and it does show two different regulators one is a three relay for the idiot light and one is for the ammeter and it is a two relay type. Sounds like you may have the wrong one.

jhow66 · 01-25-2006, 12:04 AM

Thanks 'Vet- will check it out tomorrow.

01-24-2006, 12:20 AM	#1
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Which voltage regulator? Had to change the voltage regulator on my '65 GMC (.060 over 350) as it cooked my battery. Are there different ones for idiot lights and amp gauges? Charges fine now but the idiot light does not work with new regulator-light does not come on when you turn the switch on.(light is ok as I hooked the old reg. back to harness and grounded the reg. and it works as it is supposed to). __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

01-24-2006, 02:50 AM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Which voltage regulator? Just some thoughts on this. I am curious if the resistance on the new regulator might be be too high to light the idiot light with the key on and engine off or any other non charge state. I would measure the ohms between the brown terminal and the regulator ground and compare that with the old one. I believe that the points are closed on that electromagnet and when the key is on(engine off) or the alternator isn't putting out volts the brown wire grounds through that and lights the charging light and when the engine starts the brown wire feeds the alternator field and the alternator output will open the regulator points and turn off the light. Anyways measure the resistance on the terminals to ground and compare them with the old one. There may be a difference between the years. If the old one was overcharging then the points may have stuck on it and it wouldn't be an accurate comparison. Does the light come on with the harness plug disconnected? __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

01-24-2006, 03:50 AM	#3
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Re: Which voltage regulator? I just looked in my Motors manual and it does show two different regulators one is a three relay for the idiot light and one is for the ammeter and it is a two relay type. Sounds like you may have the wrong one. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

01-25-2006, 12:04 AM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Re: Which voltage regulator? Thanks 'Vet- will check it out tomorrow. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer



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