Gas/temp gauges not working - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*JCampbell* · 08-26-2012, 04:20 AM

The fuel gauge and the temp gauge on my new '84 C10 aren't working. It's a dual tank set up, and the gauge reads waaay past full on either side. Temp gauge stays at the bottom of the temp range and doesn't move.

Any ideas?

motornut · 08-27-2012, 04:43 PM

high gas can mean the ground is bad from the tank to frame or sender unit is disconnected
behind the cluster the harness goes down to one ground wire
i'd check those out

**hatzie** · 08-27-2012, 09:14 PM

Fuel gauge sender wire shorted to ground reads empty. Unplugged reads @ 3:00.
Way past full on both gauges likely means the sender wire has a break between the tank and gauge.
The valve switches the gauge between left and right tanks. Check the DPDT switch inside the valve.
There's a disconnect in the wire between the bulkhead plug & the valve I've found unplugged.
Unplugged senders would do this... Damaged frame to tank grounds will cause this behaviour too. But this would be on both tanks.

Temp sender is probably just unplugged. Cold or 0 degrees is infinite resistance. Pegged at hot is dead shorted.

*JCampbell* · 08-31-2012, 01:14 AM

I'll check it out this weekend. I pulled the cluster last weekend to check connections and whatnot and now it seems as though I either get a reading of a full tank, or a half tank. Not sure what to make of that.

Also, I'm pretty sure my tanks aren't switching. I think I'm running off the left side. when I switch to the right tank, I get no activity in the fuel gauge, nor can I hear the solenoid clicking over. How do I test to see if the issue is in the switch inside the cab, or the solenoid near the tanks?

08-26-2012, 04:20 AM	#1
JCampbell Account Suspended Join Date: Apr 2008 Location: Hesperia, Ca Posts: 1,332	Gas/temp gauges not working The fuel gauge and the temp gauge on my new '84 C10 aren't working. It's a dual tank set up, and the gauge reads waaay past full on either side. Temp gauge stays at the bottom of the temp range and doesn't move. Any ideas?

08-27-2012, 04:43 PM	#2
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: Gas/temp gauges not working high gas can mean the ground is bad from the tank to frame or sender unit is disconnected behind the cluster the harness goes down to one ground wire i'd check those out Attached Images __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350

08-27-2012, 09:14 PM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: Gas/temp gauges not working Fuel gauge sender wire shorted to ground reads empty. Unplugged reads @ 3:00. Way past full on both gauges likely means the sender wire has a break between the tank and gauge. The valve switches the gauge between left and right tanks. Check the DPDT switch inside the valve. There's a disconnect in the wire between the bulkhead plug & the valve I've found unplugged. Unplugged senders would do this... Damaged frame to tank grounds will cause this behaviour too. But this would be on both tanks. Temp sender is probably just unplugged. Cold or 0 degrees is infinite resistance. Pegged at hot is dead shorted. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

08-31-2012, 01:14 AM	#4
JCampbell Account Suspended Join Date: Apr 2008 Location: Hesperia, Ca Posts: 1,332	Re: Gas/temp gauges not working I'll check it out this weekend. I pulled the cluster last weekend to check connections and whatnot and now it seems as though I either get a reading of a full tank, or a half tank. Not sure what to make of that. Also, I'm pretty sure my tanks aren't switching. I think I'm running off the left side. when I switch to the right tank, I get no activity in the fuel gauge, nor can I hear the solenoid clicking over. How do I test to see if the issue is in the switch inside the cab, or the solenoid near the tanks?



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