GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Gauge Cluster Repair
Gauge Cluster Repair [message #234057] Thu, 26 December 2013 19:50 Go to next message
Richard Andis is currently offline  Richard Andis   United States
Messages: 261
Registered: January 2013
Location: HELL Paso, TX
Karma: 0
Senior Member
While transplanting the circuit board on the back of the gauge cluster I neglected to document a few things.

First thing I discovered were that the ballast resistors for the gauges were color coded. There was a green, blue, and a red one (marked on the back). Anybody know which resistor goes to which gauge?

Via search, I've discovered Water Temp uses a red one.


Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)

[Updated on: Thu, 26 December 2013 19:58]

Report message to a moderator

Re: Gauge Cluster Repair [message #234072 is a reply to message #234057] Thu, 26 December 2013 21:19 Go to previous messageGo to next message
KevinZ is currently offline  KevinZ   United States
Messages: 20
Registered: November 2013
Location: Oswego NY
Karma: 0
Junior Member
We have a shop that rebuilds automotive dash assemblies in our area, I'll check with them tomorrow.

KZ Oswego, NY
Re: Gauge Cluster Repair [message #234202 is a reply to message #234072] Fri, 27 December 2013 21:19 Go to previous messageGo to next message
Richard Andis is currently offline  Richard Andis   United States
Messages: 261
Registered: January 2013
Location: HELL Paso, TX
Karma: 0
Senior Member
Seeing how I doubt anybody has a AC-GG3 tester,....Is there any good way to bench test an individual gauge on the cluster.

Looks to me that if you connect GROUND from a 12VDC power source to the gauge body and POSITIVE to PIN F of the connector, that should cause all of the gauge needles to MAX out since no senders are connected.

Additionally, using the mentioned set-up, you should then be able to connect a 0-90 ohm variable resistor to the appropriate pin below and get an corresponding needle movement based on the value of the resistor.

C - Fuel
D - Oil Pressure
H - Engine Temp



Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)

[Updated on: Fri, 27 December 2013 21:20]

Report message to a moderator

Re: Gauge Cluster Repair [message #234485 is a reply to message #234202] Mon, 30 December 2013 18:10 Go to previous messageGo to next message
Richard Andis is currently offline  Richard Andis   United States
Messages: 261
Registered: January 2013
Location: HELL Paso, TX
Karma: 0
Senior Member
Still working this problem out. I think I got just about everything working again but the Water Temp Gauge. When I disconnect the wire at the temp sensor it zeros out on the gauge and when I ground the wire the needle only moves half way up the scale.

I took a reading of the sensor with the engine running and read 195 ohms (sensor terminal to ground). It continued to climb to about 200 ohms and them level out. Anybody know the range of the temp sensor (in ohms)?


Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)
Re: Gauge Cluster Repair [message #234501 is a reply to message #234485] Mon, 30 December 2013 19:50 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
Messages: 4508
Registered: April 2011
Karma: 39
Senior Member
Richard Andis wrote on Mon, 30 December 2013 18:10

Still working this problem out. I think I got just about everything working again but the Water Temp Gauge. When I disconnect the wire at the temp sensor it zeros out on the gauge and when I ground the wire the needle only moves half way up the scale.

I took a reading of the sensor with the engine running and read 195 ohms (sensor terminal to ground). It continued to climb to about 200 ohms and them level out. Anybody know the range of the temp sensor (in ohms)?
Someplace on this forum I read that if you replace the stock sending unit with a Napa TS-6469, the stock gauge will read higher. I understand that with the stock setup, when the gauge reads halfway, the coolant is around 250 degrees F. In other words, already overheated. With the Napa replacement sender, halfway is around 200F.
Re: Gauge Cluster Repair [message #234509 is a reply to message #234501] Mon, 30 December 2013 20:38 Go to previous messageGo to next message
Richard Andis is currently offline  Richard Andis   United States
Messages: 261
Registered: January 2013
Location: HELL Paso, TX
Karma: 0
Senior Member
A Hamilto wrote on Mon, 30 December 2013 19:50

Someplace on this forum I read that if you replace the stock sending unit with a Napa TS-6469, the stock gauge will read higher. I understand that with the stock setup, when the gauge reads halfway, the coolant is around 250 degrees F. In other words, already overheated. With the Napa replacement sender, halfway is around 200F.


I'm using a spare VDO fuel gauge at a test instrument. It operates in the 10-90 ohm range. When I do the quick test then needle goes to full range (open) or zero (grounded) as expected.

The problem is that my OEM gauge needle is only to going half way when you ground the sensor wire. I believe it should peg it to full. I'm starting to believe that one of the windings may be bad.

No Resistance (grounded) = Full Swing
Infinite Resistance (open or disconnected) = 0 Swing.

This should happen irrespective of sensor values. This little "test" should work on most electrical fuel, oil, and water temp gauges. Don't even have to start the engine. Just set the key to ACC.


I found this link with regard to the resistor color codes on back
of the gauges. Might be useful
http://www.europeancorvette.com/html/console_gauges.htm


Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)

[Updated on: Mon, 30 December 2013 21:27]

Report message to a moderator

Re: [GMCnet] Gauge Cluster Repair [message #234534 is a reply to message #234509] Tue, 31 December 2013 00:39 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Richard,

You should find that only the fuel gauge and perhaps the LPG sender are 90
Ohms. I don't recall the range on the oil pressure or temperature senders,
but they're much higher. I periodically set up test apparatus and
calibrate a few. In fact, I've got about 6 temperature senders on the
bench with the apparatus right now.

Hah! Just remembered that I posted photos of a calibration session some
years ago. Maybe this will help:

http://www.gmcmhphotos.com/photos/g3443-temperature-gauges-calibration.html


Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL
www.gmcwipersetc.com


On Mon, Dec 30, 2013 at 9:38 PM, Richard Andis <randis2@elp.rr.com> wrote:

>
>
> A Hamilto wrote on Mon, 30 December 2013 19:50
> > Someplace on this forum I read that if you replace the stock sending
> unit with a Napa TS-6469, the stock gauge will read higher. I understand
> that with the stock setup, when the gauge reads halfway, the coolant is
> around 250 degrees F. In other words, already overheated. With the Napa
> replacement sender, halfway is around 200F.
>
>
> I'm using a spare VDO fuel gauge at a test instrument. It operates in the
> 10-90 ohm range. When I do the quick test then needle goes to full range
> (open) or zero (grounded) as expected.
>
> The problem is that my OEM gauge needle is only to going half way when you
> ground the sensor wire. I believe it should peg it to full. I'm starting to
> believe that one of the windings may be bad.
>
> No Resistance (grounded) = Full Swing
> Infinite Resistance (open or disconnected) = 0 Swing.
>
> This should happen irrespective of sensor values. This little "test"
> should work on most electrical fuel, oil, and water temp gauges. Don't even
> have to start the engine. Just set the key to ACC.
>
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Gauge Cluster Repair [message #234558 is a reply to message #234534] Tue, 31 December 2013 08:52 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
Messages: 7117
Registered: August 2005
Karma: 2
Senior Member
and this is what i had
http://gmcmotorhome.info/engine.html#sender

gene


On Mon, Dec 30, 2013 at 10:39 PM, Ken Henderson <hend4800@bellsouth.net>wrote:

> Richard,
>
> You should find that only the fuel gauge and perhaps the LPG sender are 90
> Ohms. I don't recall the range on the oil pressure or temperature senders,
> but they're much higher. I periodically set up test apparatus and
> calibrate a few. In fact, I've got about 6 temperature senders on the
> bench with the apparatus right now.
>
> Hah! Just remembered that I posted photos of a calibration session some
> years ago. Maybe this will help:
>
> http://www.gmcmhphotos.com/photos/g3443-temperature-gauges-calibration.html
>
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI & EBL
> www.gmcwipersetc.com
>
>
> On Mon, Dec 30, 2013 at 9:38 PM, Richard Andis <randis2@elp.rr.com> wrote:
>
> >
> >
> > A Hamilto wrote on Mon, 30 December 2013 19:50
> > > Someplace on this forum I read that if you replace the stock sending
> > unit with a Napa TS-6469, the stock gauge will read higher. I understand
> > that with the stock setup, when the gauge reads halfway, the coolant is
> > around 250 degrees F. In other words, already overheated. With the Napa
> > replacement sender, halfway is around 200F.
> >
> >
> > I'm using a spare VDO fuel gauge at a test instrument. It operates in the
> > 10-90 ohm range. When I do the quick test then needle goes to full range
> > (open) or zero (grounded) as expected.
> >
> > The problem is that my OEM gauge needle is only to going half way when
> you
> > ground the sensor wire. I believe it should peg it to full. I'm starting
> to
> > believe that one of the windings may be bad.
> >
> > No Resistance (grounded) = Full Swing
> > Infinite Resistance (open or disconnected) = 0 Swing.
> >
> > This should happen irrespective of sensor values. This little "test"
> > should work on most electrical fuel, oil, and water temp gauges. Don't
> even
> > have to start the engine. Just set the key to ACC.
> >
> >
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>



--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Re: [GMCnet] Gauge Cluster Repair [message #234755 is a reply to message #234501] Wed, 01 January 2014 19:11 Go to previous messageGo to next message
Bruce Hart is currently offline  Bruce Hart   United States
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
Senior Member
I bought the Napa TS-6469 sending unit and it read the same as the OEM unit.


On Mon, Dec 30, 2013 at 6:50 PM, A. <markbb1@netzero.com> wrote:

>
>
> Richard Andis wrote on Mon, 30 December 2013 18:10
> > Still working this problem out. I think I got just about everything
> working again but the Water Temp Gauge. When I disconnect the wire at the
> temp sensor it zeros out on the gauge and when I ground the wire the needle
> only moves half way up the scale.
> >
> > I took a reading of the sensor with the engine running and read 195 ohms
> (sensor terminal to ground). It continued to climb to about 200 ohms and
> them level out. Anybody know the range of the temp sensor (in ohms)?
> Someplace on this forum I read that if you replace the stock sending unit
> with a Napa TS-6469, the stock gauge will read higher. I understand that
> with the stock setup, when the gauge reads halfway, the coolant is around
> 250 degrees F. In other words, already overheated. With the Napa
> replacement sender, halfway is around 200F.
> --
> '73 23' Sequoia For Sale
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> CanyonLands most likely for a parts coach. Sequoia being restored to
> service.
> _______________________________________________
> 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
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist



Bruce Hart 1976 Palm Beach 1977 28' Kingsley La Grange, Wyoming
Re: [GMCnet] Gauge Cluster Repair [message #234790 is a reply to message #234755] Thu, 02 January 2014 06:35 Go to previous message
Loffen is currently offline  Loffen   Norway
Messages: 1087
Registered: August 2013
Location: Norway
Karma: 1
Senior Member
The temp sender are from 0 to around 700 Ohm

Here is a good link to a PDF, From the Corvette forum but it is the same for us.

http://www.google.no/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&ved=0CH8QFjAJ&url=http%3A%2F%2Fwww.lbfun.com%2Fwarehouse%2F tech_info%2Fgauges%2520%26%2520instruments%2FTemp-Sending-Unit-and-GaugeCF-Thread.pdf&ei=b1rFUpXjK4GwyAOn_IEo&usg=AFQjCNFRprvVJL7DNATUhUq5eN4d j7vrSQ&bvm=bv.58187178,d.bGQ


1973 23' # 1848 Sky Blue Glacier called Baby Blue and a 1973 26'-3 # 1460 Parrot green Seqouia Known as the Big Green, And sold my 1973 26'-2 # 581 White Canyon lands under the name Dobbelt trøbbel in Norway
Previous Topic: [GMCnet] Aerogel Insulation
Next Topic: [GMCnet] black tank frame cut out
Goto Forum:
  


Current Time: Fri Oct 04 07:31:32 CDT 2024

Total time taken to generate the page: 0.01510 seconds