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Need some electrical guidance!! [message #254381]

Fri, 04 July 2014 17:22

Bruce Hart

Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming

Karma: 5

Senior Member

Over the last couple of days I have installed a volt meter, vacuum gauge, temp gauge with a 6 position selector switch, tach, and a dual air gauge that all will light up at night. I have two questions, first what would be the best power source to splice into and second on a test run I used an Amprobe to determine amount of amps that I was drawing. After zeroing out the Amprobe I got 0.2 amps on the meter. I am running 16 gauge wire so what size fuse should I install?

Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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Re: Need some electrical guidance!! [message #254384 is a reply to message #254381]

Fri, 04 July 2014 17:38

glenn2726

Messages: 234
Registered: June 2014
Location: Topeka, Kansas

Karma: 2

Senior Member

Hi Bruce, since you are going to want it to light up at night then I would guess you should hook it up to the gray wire coming out of the fuse box behind the glovebox. That gray wire gets it's power from the headlight switch. When switch is off no power, pull on...power. So if your gauges have a separate lighting wire this would be the way to go. That gray wire goes to you dash lights, there is one for your radio, and also one to your AC/Htr controls, all for back lighting at night. My 1974 uses the last fuse on the lower right of the fuse panel, it is the smallest fuse there so easy to find. As for your gauges you can add a connection to the center of that fuse box and just put a fuse in line to your gauges, should be able to find out fuse size by seeing what was recommended for each gauge, minus lighting if you have separate light connection...Good Luck, Glenn

Glenn W Topeka, KS 1974 GMC 26 ft. Color:Camel Interior:Canyon Land Side Bath, Rear Sitting Area

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Re: [GMCnet] Need some electrical guidance!! [message #254389 is a reply to message #254384]

Fri, 04 July 2014 19:00

Bruce Hart

Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming

Karma: 5

Senior Member

Glenn,
I took the back cover off the dash and was able to find a grey wire (I
recalled from the previous post the other day) it was detached on a female
connector with an 1/2 inch yellow wire sticking out out of it. I used this
wire for to power the light circuits on the gauges. I powered up my lights
on Wednesday night and all was good. Thursday I had no power to the dash
lights, running lights, tail lights, and dome lights. Fuses all appeared
good. Got my maintenance manual (1975 & 1976) out page 12-7 is an
illustration of the fuse panel. I started to check fuses with a meter.
Found the 20a fuse to side marker, tail, dome, license plate lights did not
have continuity. Replaced the fuse and all is working again as well as the
dash lights(?). Second time I have found a fuse that was bad but visually
it looking good.

On Fri, Jul 4, 2014 at 4:38 PM, Glenn Whitt wrote:

> Hi Bruce, since you are going to want it to light up at night then I would
> guess you should hook it up to the gray wire coming out of the fuse box
> behind the glovebox. That gray wire gets it's power from the headlight
> switch. When switch is off no power, pull on...power. So if your gauges
> have
> a separate lighting wire this would be the way to go. That gray wire goes
> to you dash lights, there is one for your radio, and also one to your
> AC/Htr controls, all for back lighting at night. My 1974 uses the last
> fuse on the lower right of the fuse panel, it is the smallest fuse there so
> easy to find. As for your gauges you can add a connection to the center
> of that fuse box and just put a fuse in line to your gauges, should be able
> to find out fuse size by seeing what was recommended for each gauge, minus
> lighting if you have separate light connection...Good Luck, Glenn
> --
> Glenn W
> Topeka, KS
> 1974 GMC 26 ft. Color:Camel Interior:Canyon Land
> Side Bath, Rear Sitting Area
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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Re: Need some electrical guidance!! [message #254395 is a reply to message #254381]

Fri, 04 July 2014 19:57

glenn2726

Messages: 234
Registered: June 2014
Location: Topeka, Kansas

Karma: 2

Senior Member

Glad you found one of those troublesome fuses, I'm going to upgrade my fuse blocks when I get everything else done...save a lot of headaches. Glenn

Glenn W Topeka, KS 1974 GMC 26 ft. Color:Camel Interior:Canyon Land Side Bath, Rear Sitting Area

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Re: [GMCnet] Need some electrical guidance!! [message #254407 is a reply to message #254389]

Fri, 04 July 2014 22:52

A Hamilto

Messages: 4508
Registered: April 2011

Karma: 39

Senior Member

Bruce Hart wrote on Fri, 04 July 2014 19:00

Glenn,
I took the back cover off the dash and was able to find a grey wire (I recalled from the previous post the other day) it was detached on a female connector with an 1/2 inch yellow wire sticking out out of it. I used this wire for to power the light circuits on the gauges. I powered up my lights on Wednesday night and all was good. Thursday I had no power to the dash lights, running lights, tail lights, and dome lights. Fuses all appeared good. Got my maintenance manual (1975 & 1976) out page 12-7 is an illustration of the fuse panel. I started to check fuses with a meter. Found the 20a fuse to side marker, tail, dome, license plate lights did not have continuity. Replaced the fuse and all is working again as well as the dash lights(?). Second time I have found a fuse that was bad but visually it looking good.

Whenever you don't have dash lights, check to see if you have tail lights. Manufacturers have been wiring vehicles that way for decades to tell the operator the tail lights are not working. When the tail light fuse blows, you lose dash lights.

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Re: [GMCnet] Need some electrical guidance!! [message #254416 is a reply to message #254407]

Sat, 05 July 2014 06:34

Bruce Hart

Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming

Karma: 5

Senior Member

Thanks Mark,
It occurred to me when I woke up this morning that the wire size will
determine the fuse size,
16 ga. wire will handle 7.5amps or less. With my current draw so little I
will go with a 5 amp fuse.

http://www.bcae1.com/wirequickreferenceprintable01.htm

I will use a fuse tap to install my power wire.

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Fuse-Tap-Fuse-Taps-For-AGC-Roung-Glass-Fuses/_/R-NW_785131_0282529028

On Fri, Jul 4, 2014 at 9:52 PM, A. wrote:

> Bruce Hart wrote on Fri, 04 July 2014 19:00
>> Glenn,
>> I took the back cover off the dash and was able to find a grey wire (I
> recalled from the previous post the other day) it was detached on a female
>> connector with an 1/2 inch yellow wire sticking out out of it. I used
> this wire for to power the light circuits on the gauges. I powered up my
>> lights on Wednesday night and all was good. Thursday I had no power to
> the dash lights, running lights, tail lights, and dome lights. Fuses all
>> appeared good. Got my maintenance manual (1975 & 1976) out page 12-7 is
> an illustration of the fuse panel. I started to check fuses with a meter.
>> Found the 20a fuse to side marker, tail, dome, license plate lights did
> not have continuity. Replaced the fuse and all is working again as well as
>> the dash lights(?). Second time I have found a fuse that was bad but
> visually it looking good.
> Whenever you don't have dash lights, check to see if you have tail lights.
> Manufacturers have been wiring vehicles that way for decades to tell the
> operator the tail lights are not working. When the tail light fuse blows,
> you lose dash lights.
> --
> '73 23' Sequoia For Sale
> '73 23' CanyonLands For Sale
> Upper Alabama
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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Re: Need some electrical guidance!! [message #254430 is a reply to message #254381]

Sat, 05 July 2014 10:36

SteveW

Messages: 538
Registered: June 2005
Location: Southern California - Ora...

Karma: 1

Senior Member

Bruce -

What's up with the temperature gauge and six position selector switch ??

Are you really going to measure temperature in six different places ??

That's interesting to me....

Thanks,

Steve W
1973 23'
Southern California

Steve W 1973 : 23' Southern California

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Re: [GMCnet] Need some electrical guidance!! [message #254431 is a reply to message #254430]

Sat, 05 July 2014 10:46

Bruce Hart

Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming

Karma: 5

Senior Member

Sensors on, transmission pan, oil pan, water, and possible the final drive
pan with two extra positions left over. Radio shack only had a six
position switch at the time I bought it.

On Sat, Jul 5, 2014 at 9:36 AM, Steve Weinstock
wrote:

> Bruce -
>
> What's up with the temperature gauge and six position selector switch ??
>
> Are you really going to measure temperature in six different places ??
>
> That's interesting to me....
>
> Thanks,
>
> Steve W
> 1973 23'
> Southern California
>
>
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--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming

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