temp gauge and volt gauge - help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ssjones · 04-26-2005, 10:19 PM

I have a 1972 c20. The volt gauge and temp gauge are not working. All the other gauges work fine (oil, fuel, rpm) any idea where to start looking for the problem? I can see the instrument panel - should there be a wire running to the individual gauges on the nut and bolt on the cluster. Any help is appreciated. Thanks.

Longhorn Man · 04-26-2005, 10:52 PM

Your amp guage is probably simple.
Look under the hood...along the fenders...both sides. you are looking for a little black foot ball lookin thing...2 inches long at best...in the wire harnesses. Pop them open and replace the 2 inline fuses.
Your temp guage, look ont eh dvr side head towards the front, and look for a sending unit with a green wire. No wire? Find it and plug it in.
If the wire IS there, and plugged in, then unplug it, and ground it. Turn on the ignition, if the guage pegs out to way overheat...then you need a new sending unit. If it doesn't respond, then it could be the green wire cut on down the line, no power to the guage, or a bum guage.
it's probably the sending unit or the green wire...at least from my experiance.

jhow66 · 04-26-2005, 10:54 PM

Amp gauge (not volt on these trucks)--There are 2 fuse ( 4 amp) holders at each corner of rad. support. Pull apart and check. If both are ok you will have to remove dash to check printed circuit- if that is ok change the resistor on the gauge (the little white thing on gauge).

Temp gauge--remove wire (green) on sender on motor (on side of driver side head). Turn on switch and have someone ground the green wire to motor (touch and release). If gauge moves to the right it is ok-change sender. If it does not move check green wire back to printed circuit. If ok ckeck printed circuit to gauge. If ok change resistor on gauge. They can be found here:
www.fix-a-gauge.com
Note--the above info carries no warranty or guarantee.

Robert1970C20rstbukt · 04-26-2005, 11:10 PM

Not trying to hijack the thread, but what kind of resistor do you use to replace the original one on the ammeter? I never got the one in my truck to work and the only thing left that could be the problem is the resistor.

jhow66 · 04-26-2005, 11:29 PM

These : (circled in green)
can be purchased here:
www.fix-a-gauge.com

chickenwing · 04-27-2005, 11:34 AM

thanks for the link. Saved it for future projects.

ssjones · 04-27-2005, 11:43 PM

Thanks for the replies. Looks like I need a new sending unit and the fuse was blown.

04-26-2005, 10:19 PM	#1
ssjones Registered User Join Date: Mar 2005 Location: Scottsdale, Arizona Posts: 98	temp gauge and volt gauge - help I have a 1972 c20. The volt gauge and temp gauge are not working. All the other gauges work fine (oil, fuel, rpm) any idea where to start looking for the problem? I can see the instrument panel - should there be a wire running to the individual gauges on the nut and bolt on the cluster. Any help is appreciated. Thanks. __________________ 1972 Chevy Cheyenne 20 1979 Chevy Camaro 2007 Chevy Avalanche 2005 Mini Cooper

04-26-2005, 10:54 PM	#3
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Amp gauge (not volt on these trucks)--There are 2 fuse ( 4 amp) holders at each corner of rad. support. Pull apart and check. If both are ok you will have to remove dash to check printed circuit- if that is ok change the resistor on the gauge (the little white thing on gauge). Temp gauge--remove wire (green) on sender on motor (on side of driver side head). Turn on switch and have someone ground the green wire to motor (touch and release). If gauge moves to the right it is ok-change sender. If it does not move check green wire back to printed circuit. If ok ckeck printed circuit to gauge. If ok change resistor on gauge. They can be found here: www.fix-a-gauge.com Note--the above info carries no warranty or guarantee. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

04-26-2005, 11:10 PM	#4
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	Not trying to hijack the thread, but what kind of resistor do you use to replace the original one on the ammeter? I never got the one in my truck to work and the only thing left that could be the problem is the resistor. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

04-26-2005, 11:29 PM	#5
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	These : (circled in green) can be purchased here: www.fix-a-gauge.com Attached Images __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

04-27-2005, 11:34 AM	#6
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	thanks for the link. Saved it for future projects. __________________ The truck... you hear that? No really, you did hear that?!!!

04-26-2005, 10:52 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Your amp guage is probably simple. Look under the hood...along the fenders...both sides. you are looking for a little black foot ball lookin thing...2 inches long at best...in the wire harnesses. Pop them open and replace the 2 inline fuses. Your temp guage, look ont eh dvr side head towards the front, and look for a sending unit with a green wire. No wire? Find it and plug it in. If the wire IS there, and plugged in, then unplug it, and ground it. Turn on the ignition, if the guage pegs out to way overheat...then you need a new sending unit. If it doesn't respond, then it could be the green wire cut on down the line, no power to the guage, or a bum guage. it's probably the sending unit or the green wire...at least from my experiance.

04-27-2005, 11:43 PM	#7
ssjones Registered User Join Date: Mar 2005 Location: Scottsdale, Arizona Posts: 98	Thanks for the replies. Looks like I need a new sending unit and the fuse was blown. __________________ 1972 Chevy Cheyenne 20 1979 Chevy Camaro 2007 Chevy Avalanche 2005 Mini Cooper



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