Home » Public Forums » GMCnet » [GMCnet] blown fuses: alternator saga, continues...
| [GMCnet] blown fuses: alternator saga, continues... [message #303636] |
Fri, 15 July 2016 18:57  |
Ek_Lektro
Messages: 167
Registered: March 2011
Karma: 2
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Senior Member |
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Greetings GMC compadres,
Continued from previous posts a few weeks ago)… the plot thickens:
background info: The alternator (Autozone Duralast 100amp installed just this past december) was putting out 16 volts…
soon started creeping up to 17 volts.. so eventually we blew a headlight.
Then last month, repeatedly blew the turn signal fuse, so we replaced the alt under lifetime warranty,
plus put in a new isolator for good measure (you might recall my posting;
Even though we don’t even use the alternator for charging our oversized house battery banks, we put one back in
solely for the feedback voltage. also put in a new engine battery, new lugs, cleaned alternator connectors, etc.
Fired it up to find that its putting out a consistent 15.9 to 16v at the post and 15.5 at the battery.
Though i was disappointed not to see that 14.5v magic number, i was told that 15.5-16v is the high end
of normal… (really?)
At that point, I needed to use the coach a bit, and see what happened.
After about 100 miles, the turn signals no longer blinked, but would stay on full bright;
so i’d have to manually “blink” them. checked alternator voltage for any variations, but still very consistent
at 15.5 to 16v. One week later, last night, had to get back to driving...
After 20 miles, the dash instrument panels lights go out, as well as the tail lights and marker lights!
but fortunately the headlights and brake lights remained working, made it to my destination;
tried replacing the tail-light / marker lights fuse roadside, but i didn’t have the exact same type,
so it only lasted a few miles. the tiny fuse for the instrument panels lights is showing continuity,
tried wiggling it around, no luck.
Please consider, since i had previously put on hundreds of miles with a 16v to 17v alternator,
my concern is that there’s now something else gone wrong (with things blowing at 15.5 to 16v
(also, I’m currently many miles from an auto parts shop, gonna try to stay up here for the weekend,
and i don’t have the exact fuses needed, but i’m looking around,
and i’ve got basic tools :)
Qs:
Can a slightly loose belt cause voltage fluctuation to the level of blowing fuses?? mine has a bit of squeal on start-up.
Plus when i’d manually “blink” the turn signals, interestingly, sometimes the alt belt would squeal a little
Is Duralast indeed Dura-crap?? The same model alternator was putting out funky voltage on my Birchhaven down in Mexico
a couple months ago, but after an auto-electric shop put in a new regulator, its doing a consistent 14.5 volts for several hundred miles now.
Yeah, the ’78 Eleganza is giving me some fits currently, probably jealous
of all the time and money poured into the ’76 Birchhaven custom work the past few years… !
Any advice appreciated, Thanks much!
Greg
SolarSonic / Los Angeles
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| Re: [GMCnet] blown fuses: alternator saga, continues... [message #303637 is a reply to message #303636] |
Fri, 15 July 2016 19:28  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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14.5 is the high end of normal. 17 will hurt stuff long term. You should
only see that immediately after startup or heavy battery drain. Check the
two conductors that exite the slip rings. If loose, bad ju ju.
Jim Hupy
On Jul 15, 2016 4:59 PM, "Ek_Lektro" wrote:
> Greetings GMC compadres,
> Continued from previous posts a few weeks ago)… the plot thickens:
> background info: The alternator (Autozone Duralast 100amp installed just
> this past december) was putting out 16 volts…
> soon started creeping up to 17 volts.. so eventually we blew a headlight.
> Then last month, repeatedly blew the turn signal fuse, so we replaced the
> alt under lifetime warranty,
> plus put in a new isolator for good measure (you might recall my posting;
> Even though we don’t even use the alternator for charging our oversized
> house battery banks, we put one back in
> solely for the feedback voltage. also put in a new engine battery, new
> lugs, cleaned alternator connectors, etc.
>
> Fired it up to find that its putting out a consistent 15.9 to 16v at the
> post and 15.5 at the battery.
> Though i was disappointed not to see that 14.5v magic number, i was told
> that 15.5-16v is the high end
> of normal… (really?)
> At that point, I needed to use the coach a bit, and see what happened.
> After about 100 miles, the turn signals no longer blinked, but would stay
> on full bright;
> so i’d have to manually “blink” them. checked alternator voltage for any
> variations, but still very consistent
> at 15.5 to 16v. One week later, last night, had to get back to driving...
> After 20 miles, the dash instrument panels lights go out, as well as the
> tail lights and marker lights!
> but fortunately the headlights and brake lights remained working, made it
> to my destination;
> tried replacing the tail-light / marker lights fuse roadside, but i didn’t
> have the exact same type,
> so it only lasted a few miles. the tiny fuse for the instrument panels
> lights is showing continuity,
> tried wiggling it around, no luck.
>
> Please consider, since i had previously put on hundreds of miles with a
> 16v to 17v alternator,
> my concern is that there’s now something else gone wrong (with things
> blowing at 15.5 to 16v
> (also, I’m currently many miles from an auto parts shop, gonna try to stay
> up here for the weekend,
> and i don’t have the exact fuses needed, but i’m looking around,
> and i’ve got basic tools :)
>
> Qs:
> Can a slightly loose belt cause voltage fluctuation to the level of
> blowing fuses?? mine has a bit of squeal on start-up.
> Plus when i’d manually “blink” the turn signals, interestingly, sometimes
> the alt belt would squeal a little
>
> Is Duralast indeed Dura-crap?? The same model alternator was putting out
> funky voltage on my Birchhaven down in Mexico
> a couple months ago, but after an auto-electric shop put in a new
> regulator, its doing a consistent 14.5 volts for several hundred miles now.
>
> Yeah, the ’78 Eleganza is giving me some fits currently, probably jealous
> of all the time and money poured into the ’76 Birchhaven custom work the
> past few years… !
>
> Any advice appreciated, Thanks much!
> Greg
> SolarSonic / Los Angeles
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] blown fuses: alternator saga, continues... [message #303639 is a reply to message #303636] |
Fri, 15 July 2016 20:03 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I would be looking very closely at the voltage sense line at the alternator. If it is low then you will have the problem that you are describing (alternator over voltage.
IF the sense line voltage is good, I would be checking the terminals that plug into the back of the alternator. I had your problem when I went to the Dothan rally this spring. After changing the alternator, the problem stayed the same (over voltage. The problem eventually turned out to be the connectors that plugged into the back of the alternator. The terminals themselves had lost tension over the years and were not making a good connection. I squeezed them together a little bit with a pair of pliers and have not seen the over voltage problem again.
Two other GMCers have sent me off-net notes stating that they have found the same problem with alternator connectors on their GMCs.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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