Truck not shutting off after alt swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kansasc10 · 10-23-2015, 02:02 AM

stumped and need some help....I installed a new wiring harness from painless performance a while ago and when I got it all installed the truck didnt shut off. So I installed the diode from radio shack that Painless recommended if the problem arose and it fixed the issue...truck shuts right off and has worked fine great ever since.

Fast foward 6-8 months and my battery starts dying everytime I drive it for more than for 10 or 15 minutes. So I stop by the parts store by my house and had my alt and battery tested and they tell me my alternator is bad. So out comes the wallet and I buy a new alt. they had in stock. I get the thing put in, connections made and take it for a drive. Everything seems to be working fine but when I get home, the truck refuses to shut off, just like it did before. I have to pull the alt connector to get it to shut off now. I made sure the connector was connected right and not backwards and all is good there.

The old alt has a amperage sticker on it that says 85 amps (even though the web lists it at 108 amps?) and the new alt says 63. Would the amperage difference of the two make a difference in whether it will shut off or not? Are there more differences than just amperage that Im not seeing? Is the diode now doing the opposite of what it was doing before and actually preventing shutdown?

The old alt that worked till this week was a Duralast alternator part #DL-70897. I called Autozone who carries Duralast and they said they no longer make or carry that alternator. Otherwise Id buy the same one.

http://www.autozone.com/1/products/4...t-dl70897.html

The new alt that I installed is from Advanced auto part#7127-3A.

http://shop.advanceautoparts.com/p/c...7-3a/5210100-P.

Im hoping someone here is the end all be all of alternators and knows exactly what I need to do to fix it. Whether it be buying another alt, removing the diode, chasing unicorns etc. I just want to get it fixed.
I called Painless today but they were closed. Ill try them again tomorrow but figured someone here may have a solution. Thanks all!

10-23-2015, 02:02 AM	#1
kansasc10 Registered User Join Date: May 2015 Location: Kansas Posts: 61	Truck not shutting off after alt swap stumped and need some help....I installed a new wiring harness from painless performance a while ago and when I got it all installed the truck didnt shut off. So I installed the diode from radio shack that Painless recommended if the problem arose and it fixed the issue...truck shuts right off and has worked fine great ever since. Fast foward 6-8 months and my battery starts dying everytime I drive it for more than for 10 or 15 minutes. So I stop by the parts store by my house and had my alt and battery tested and they tell me my alternator is bad. So out comes the wallet and I buy a new alt. they had in stock. I get the thing put in, connections made and take it for a drive. Everything seems to be working fine but when I get home, the truck refuses to shut off, just like it did before. I have to pull the alt connector to get it to shut off now. I made sure the connector was connected right and not backwards and all is good there. The old alt has a amperage sticker on it that says 85 amps (even though the web lists it at 108 amps?) and the new alt says 63. Would the amperage difference of the two make a difference in whether it will shut off or not? Are there more differences than just amperage that Im not seeing? Is the diode now doing the opposite of what it was doing before and actually preventing shutdown? The old alt that worked till this week was a Duralast alternator part #DL-70897. I called Autozone who carries Duralast and they said they no longer make or carry that alternator. Otherwise Id buy the same one. http://www.autozone.com/1/products/4...t-dl70897.html The new alt that I installed is from Advanced auto part#7127-3A. http://shop.advanceautoparts.com/p/c...7-3a/5210100-P. Im hoping someone here is the end all be all of alternators and knows exactly what I need to do to fix it. Whether it be buying another alt, removing the diode, chasing unicorns etc. I just want to get it fixed. I called Painless today but they were closed. Ill try them again tomorrow but figured someone here may have a solution. Thanks all!



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