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#1 |
Registered User
Join Date: Jan 2017
Location: Larkspur, Colorado
Posts: 913
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Factory ammeters never work, why?
I’ve been around these trucks for decades and never once have I seen the needle move on a factory ammeter, ever.
Thoughts? Fix? Steve weim55 Colorado |
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#2 |
Registered User
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,660
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Re: Factory ammeters never work, why?
Replace the 2 small fuses in the lines. If they're blown, you have to figure out why
__________________
72 C10 lwb fleetside -stock 350/350 combo |
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#3 |
Registered User
Join Date: Jan 2017
Location: Larkspur, Colorado
Posts: 913
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Re: Factory ammeters never work, why?
[QUOTE=68 P.O.S.;8656110]Replace the 2 small fuses in the lines. If they're blown, you have to figure out why[/QUOTE
Where are the fuses you speak of? On the contrary the 64 to 66 Trucks I’ve had the ammeters work perfectly. They will sweep 3/4 of the way to the charge side after starting and settle down to the center. With the engine turned off you can turn on lights and such and it will show a significant discharge. Steve weim55 Colorado Last edited by weim55; 01-07-2020 at 07:58 PM. |
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#4 | |
Old member
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
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![]() Quote:
Even when they work they move very little. You will have to watch it all the time to see it moving. It's not like a volt gauge. Very little movement unless you hook something really big amp draw on the battery. ![]()
__________________
1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 ![]() Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs. |
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#5 |
Registered User
Join Date: Feb 2018
Location: Doland SD
Posts: 836
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Re: Factory ammeters never work, why?
Mine moves all the time. Like when I put the headlights on. The blinkers or start. it. Or jump start some one. It goes to the the right. When running or the left when not. Frim what I can tell it basically just tells a guy when there is load on the altinater and if it's charging with the load on it.
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![]() 94 chevy k1500 350 tbi 373 rear gears 4l60e one wheel peel. Gutless 07 gmc sierra classic rcsb 4.3 lt 5 speed w/t 04 chevy Silverado 1500 ext cab 5.3 4l60e. 81 chevy Scottsdale k10 muncie sm465 Np208 10 bolt 8.2 ( Old Green) |
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#6 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,942
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Re: Factory ammeters never work, why?
The system isn't the best design as it requires that wiring between the battery, the alternator and the junction block near the horn be in perfect condition and of the factory sizing to allow the amp meter to work. Any changes to wiring size or poor connections changes the resistance balance and the meter will not respond as originally intended.
Count your lucky stars 71gmcC15 your one of the lucky ones.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#7 | |
Registered User
Join Date: Oct 2006
Location: Orland Park Il
Posts: 2,041
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Re: Factory ammeters never work, why?
Quote:
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68 GMC C3500 Longhorn DRW 67 Chevy C10 LWB 90 Mustang Gt 90 Mustang Notchback |
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#8 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,234
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Re: Factory ammeters never work, why?
Guess I'm lucky, too. If the truck has been sitting and has to crank a bit, the needle goes up about half way on the "C" side, which is about 30 Amps- if full scale is 60, and that's about what my alternator is rated at. It comes down fairly quickly, though.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#9 |
Registered User
![]() Join Date: Nov 2012
Location: BY THE CAROLINA SEA
Posts: 919
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Re: Factory ammeters never work, why?
When mine did not move for months I checked the two fuses, and they were BOTH blown. I replaced them, and now it moves when I turn the headlights on.
__________________
FRANKENTRUCK 1981 Chevrolet C10 Shortbed Stepside GRANDTRUCK 1968 Chevrolet C10 Stepside Longbed http://67-72chevytrucks.com/vboard/s...d.php?t=584617 PROJECT JIGSAW 1967 GMC C3500 GREAT WHITE 1986 Blazer M1009 |
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#10 | ||
Registered User
Join Date: Jun 2010
Location: San Diego Co.
Posts: 1,155
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Re: Factory ammeters never work, why?
Quote:
Quote:
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1972 Chevy C-10, SWB, Fleet, 350/350, PS, PB, all stock, Survivor. ![]() |
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#11 |
All about them K’s
![]() Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,276
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Re: Factory ammeters never work, why?
Mine works as well. It the most noticeable when you first start the truck. The headlights will move it a little bit not very much. Normally after about 15 seconds on the first start the needle is back to the center of the gauge.
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's ‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue ‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0 ![]() |
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#12 |
All about them K’s
![]() Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,276
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Re: Factory ammeters never work, why?
They are on either corner of the core support in little black rubber fuse holders. The fuses are really small glass fuses, I believe they are 2 or 3 amp if I remember correctly.
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's ‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue ‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0 ![]() Last edited by 57taskforce; 01-07-2020 at 08:24 PM. |
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#13 | |
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,358
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Re: Factory ammeters never work, why?
Quote:
The 64 - 66 trucks used the same exact ammeter circuit as 67 - 72. So when working properly, the behavior should be the same. However, 64 - 66 did not have the little 4 amp fuses protecting the meter movement and it's associated wiring. I've seen a few 64 - 66 wiring harnesses with melted ammeter wiring so I think adding the inline fuses to those years is a good idea. |
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#14 | |
All about them K’s
![]() Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,276
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Re: Factory ammeters never work, why?
Quote:
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's ‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue ‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0 ![]() |
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#15 | |
Registered User
Join Date: Jan 2017
Location: Larkspur, Colorado
Posts: 913
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Re: Factory ammeters never work, why?
Quote:
Great information! I will dig in on my 69 at some point soon to see if the fuses are the issue. I too would greatly prefer a voltmeter but if the amateur would work as good as the one in my 65 I would be perfectly happy. I can always tell right away if the charging system is functioning properly. Steve weim55 Colorado |
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#16 |
Registered User
![]() Join Date: Aug 2015
Location: Dunbarton, NH
Posts: 277
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Re: Factory ammeters never work, why?
Does anyone know of a source for these small fuse holders? Both of mine are missing, and I would like to find replacements that are similar.
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#17 | ||
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,358
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Re: Factory ammeters never work, why?
Quote:
Or, for a functional but not quite as original looking replacement, you could use a couple of waterproof mini ATM fuse holders such as this: https://www.amazon.com/1st-Source-MI.../dp/B00NU9AW42 Quote:
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#18 | |
Registered User
Join Date: Jun 2018
Location: Arcadia, California
Posts: 18
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Re: Factory ammeters never work, why?
Quote:
That temp light gets 12V constant from the cluster and what turns it on is if that wire gets connected to ground. If you take that grounding wire and split it in two there you can connect one end to the temp switch and one to oil. Thanks, KJ
__________________
1967 Camaro Emerald Turquoise RSSS 396, Muncie M21, 12 Bolt 3.73 Posi, Hotchkis/QA1 Suspension 1970 CST/10 Dark Olive Short bed Fleetside, 350 SBC, Muncie M21, PS/PB |
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#19 | ||
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,358
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Re: Factory ammeters never work, why?
Quote:
Quote:
I agree, the existing TEMP light could be wired up to both temp and oil pressure switches to make it function as a "check gauges" warning light. And yes, a temp switch in the pass side head on a V8 or manifold port and oil switch connected to a Tee fitting where the gauge line goes into the block would do the trick. Wiring it up to the ignition switch (like GM did with the stock TEMP & BRAKE lights) for a bulb check during start-up is a good idea too. When I said earlier, "Adding an oil pressure light into the stock gauge cluster would take a little more work though." I was thinking along the lines of what it would take to cut in a stock looking "window" and fit it with a lens with "OIL" printed on it. |
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#20 | |
Registered User
Join Date: Feb 2011
Location: Parkville, MD
Posts: 1,024
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Re: Factory ammeters never work, why?
Quote:
For oil pressure, use a T right where it comes out of the block and a pressure switch from a gauge cluster car. Another thought is the bulb test when you turn the key to start.
__________________
1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z |
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#21 | |
Senior Member
![]() Join Date: Mar 2000
Location: Saskatoon,SK,Canada
Posts: 2,476
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Re: Factory ammeters never work, why?
I did that 30 year ago. Works great.
Quote:
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Saskatoon, Saskatchewan Canada |
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#22 |
Registered User
Join Date: Feb 2011
Location: Parkville, MD
Posts: 1,024
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Re: Factory ammeters never work, why?
Mine works with the headlights, but otherwise, hard to notice. I would like to convert to a volt gauge one of these days. There are several threads on converting.
__________________
1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z |
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#23 |
Registered User
![]() Join Date: Dec 2012
Location: Vancouver, Washington
Posts: 1,644
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Re: Factory ammeters never work, why?
The volt (battery) gauge is a great update. I did it recently..
__________________
1968 Chevrolet C/10 LWB - 327, TH350 - 4/5 Drop |
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#24 |
Senior Member
![]() Join Date: Mar 2000
Location: Saskatoon,SK,Canada
Posts: 2,476
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Re: Factory ammeters never work, why?
A little info. The ammeter is a shunted ammeter. It measures the voltage drop across a known resistance. By Ohm's law that voltage drop indicates the amperage flowing across the resistance. That resistance is the wire from the alternator to the battery. As stated any change in the resistance of that connection affects the ammeter. So if you upgrade the alternator and change that wire accordingly the ammeter cannot be used unless you can insert the exact correct resistance and connect those two black wires that are fused across that resistor. The best possible thing is to replace that ammeter with a volt gauge conversion which is much more useful anyway. The only place an ammeter really belongs is in a stock survivor or resto.
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Saskatoon, Saskatchewan Canada |
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#25 | |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,942
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Re: Factory ammeters never work, why?
Quote:
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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