Temp. gauge is pegged out to max - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Southpa · 02-06-2004, 10:36 PM

I've been thru 3 mechanical gauge/sensor setups so far and decided to thoroughly investigate why the stock electrical gauge /sensor setup doesn't work. The mechanical ones lasted maybe a year each, crapola.

OK, there are no problems going from the sensor to the gauge. I checked for continuity between the end of the sensor wire (dark green) to the back of the gauge and there is current flow. So what is the roundabout route that takes me back to the sensor in the block, via ground straps etc? Are there supposed to be any wires attached to any posts on the back of the temp gauge? Mine doesn't have any. Or is the rest of the current flow supposed to go through the circuitboard/grounding system?

Either way the needle in the gauge is waaaayyyy over to the right whether the sensor is hooked up or not, that means infinite resistance, lol, no current flow. The loop is broken somewhere.

Oh, btw, the engine runs fine NO overheating problems or anything like that.

jhow66 · 02-06-2004, 11:08 PM

Bad gauge. Power----to-----+gauge- ---to----block sensor(ground)--the hotter it gets the more it grounds which moves needle farther to the right.

Southpa · 02-07-2004, 12:08 AM

I looked into replacing the gauge last year, had the whole dash out, and found that the darn gauge is spotwelded in! Any idea on how to replace w/out too much trouble?

jhow66 · 02-07-2004, 01:45 AM

Where is it welded?

Southpa · 02-07-2004, 02:38 AM

Yours looks nothing like mine. The arrow in your photo points to my temp gauge and my fuel gauge is the large one on passenger side. If I remember rightly, the lower gauges are sealed in with a spotwelded in piece of 16 ga. steel painted light green.

71 fun · 02-07-2004, 02:55 AM

Sir,
This info may help, Take the wire off the sensor and with the ignition on see if the guage is still pegged. If the sensor wire is grounded it will peg your guage. If the guage does not move with the wire disconnected I would suspect that the sensor is bad.
71 FUN

71 fun · 02-07-2004, 02:59 AM

I should finish reading prior to opening my fat fingers.
71 FUN

BUXMAN66 · 02-07-2004, 03:51 AM

dude you got yourself a bad guage........shouldn't even be in the position of what the picture shows.fuel guage is large opening to right of speedo, and the temp. guage is beside amp.guage at lower left,smaller opening (below column). getcha a new guage there's one on e-bay now for 'round $15-20 bucks.

02-06-2004, 10:36 PM	#1
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	Temp. gauge is pegged out to max I've been thru 3 mechanical gauge/sensor setups so far and decided to thoroughly investigate why the stock electrical gauge /sensor setup doesn't work. The mechanical ones lasted maybe a year each, crapola. OK, there are no problems going from the sensor to the gauge. I checked for continuity between the end of the sensor wire (dark green) to the back of the gauge and there is current flow. So what is the roundabout route that takes me back to the sensor in the block, via ground straps etc? Are there supposed to be any wires attached to any posts on the back of the temp gauge? Mine doesn't have any. Or is the rest of the current flow supposed to go through the circuitboard/grounding system? Either way the needle in the gauge is waaaayyyy over to the right whether the sensor is hooked up or not, that means infinite resistance, lol, no current flow. The loop is broken somewhere. Oh, btw, the engine runs fine NO overheating problems or anything like that. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first. Last edited by Southpa; 02-06-2004 at 10:40 PM.

02-06-2004, 11:08 PM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Bad gauge. Power----to-----+gauge- ---to----block sensor(ground)--the hotter it gets the more it grounds which moves needle farther to the right. __________________ 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

02-07-2004, 12:08 AM	#3
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	I looked into replacing the gauge last year, had the whole dash out, and found that the darn gauge is spotwelded in! Any idea on how to replace w/out too much trouble? __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

02-07-2004, 01:45 AM	#4
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Where is it welded? 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

02-07-2004, 02:38 AM	#5
Southpa Registered User Join Date: May 2000 Location: Victoria, BC, Canada Posts: 2,409	Yours looks nothing like mine. The arrow in your photo points to my temp gauge and my fuel gauge is the large one on passenger side. If I remember rightly, the lower gauges are sealed in with a spotwelded in piece of 16 ga. steel painted light green. __________________ 1970 GMC 1500 Custom Original 350/TH350 Victoria, BC, Canada You can wish in one hand and crap in the other. See which one gets filled first.

02-07-2004, 02:55 AM	#6
71 fun Registered User Join Date: Jul 2003 Location: Elko,Nv. Posts: 65	Guage pegged Sir, This info may help, Take the wire off the sensor and with the ignition on see if the guage is still pegged. If the sensor wire is grounded it will peg your guage. If the guage does not move with the wire disconnected I would suspect that the sensor is bad. 71 FUN __________________ 71 k/20 GMC 79 k/10 GMC 96 k/10 GMC

02-07-2004, 02:59 AM	#7
71 fun Registered User Join Date: Jul 2003 Location: Elko,Nv. Posts: 65	my bad I should finish reading prior to opening my fat fingers. 71 FUN __________________ 71 k/20 GMC 79 k/10 GMC 96 k/10 GMC

02-07-2004, 03:51 AM	#8
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	dude you got yourself a bad guage........shouldn't even be in the position of what the picture shows.fuel guage is large opening to right of speedo, and the temp. guage is beside amp.guage at lower left,smaller opening (below column). getcha a new guage there's one on e-bay now for 'round $15-20 bucks. __________________ '68 swb 1/2t 350/350th '86 lngbd 3/4 TON parts getter '49 gmc 1/2 t 5 window 350/350th '96 gmc sonoma sle ext-cab. hey it's a 4cyl. 5 spd and good on gas y'know?



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