Temp Sending Unit

[C10MixMaster]

Gauge parameters varied

For Truck Years: 1967 - 1973
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 76 Ω
Right Line (Hot) when sender resistance = 51 Ω
For Truck Years: 1974 - 1978
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 68 Ω
Right Line (Hot) when sender resistance = 46 Ω
For Truck Years: 1979 - 1990
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 1,365 Ω
Middle Line when sender resistance = 96 Ω
Right Line (Hot) when sender resistance = 55 Ω

I think 67-78 all used a large sender
you will probably need a gauge from the 1979 and up. (I believe the79/80 used a small sending unit)

 

[custodian]

Gauge parameters varied

For Truck Years: 1967 - 1973
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 76 Ω
Right Line (Hot) when sender resistance = 51 Ω
For Truck Years: 1974 - 1978
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 68 Ω
Right Line (Hot) when sender resistance = 46 Ω
For Truck Years: 1979 - 1990
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 1,365 Ω
Middle Line when sender resistance = 96 Ω
Right Line (Hot) when sender resistance = 55 Ω

I think 67-78 all used a large sender
you will probably need a gauge from the 1979 and up. (I believe the79/80 used a small sending unit)

Good info.

 

[MikeB]

RockAuto shows 1985 sender for gauge is AC Delco #2134793

1973 uses AC Delco #G1852

You might also want to check out the AC Delco parts catalog here: https://parts-catalog.acdelco.com/catalog/catalog_search.php

 

[MikeB]

Gauge parameters varied

For Truck Years: 1967 - 1973
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 76 Ω
Right Line (Hot) when sender resistance = 51 Ω
For Truck Years: 1974 - 1978
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 68 Ω
Right Line (Hot) when sender resistance = 46 Ω
For Truck Years: 1979 - 1990
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 1,365 Ω
Middle Line when sender resistance = 96 Ω
Right Line (Hot) when sender resistance = 55 Ω

I think 67-78 all used a large sender
you will probably need a gauge from the 1979 and up. (I believe the79/80 used a small sending unit)

 

[MikeB]

Always a good idea to check sender resistance in hot water at a few temperatures (like 100, 150, 180, 212)because I have found them to vary significantly among brands. I just got a new G1852 for my 69 C10, and had to add a 15 ohm resistor in series with it to put the needle in the middle of the gauge at 180-185 degrees. Always helps to have a 0-500 ohm potentiometer, ohmmeter, and IR temp gun to set things up if you're @nal like me!

 

[Raider L]

@custodian,

Just sayin', but at some point in rebuilding my truck and redoing my wiring, I lost the alt. wire that goes to the Red light that lights up for a moment or two right after you start your truck. It's buried in the bundle of wire under the dash. I tracked it through the fuse block from the alt. and since the factory did not wire the fuse block correctly, it disappeared where it went into the bundle in the cab. It's a tiny Brown wire. What that light tells you is that the alt. field has energized. If after a moment or two it goes out the alt. is good. If the light comes on and stays on, there's a problem with the field windings and isn't letting the armature energize. If the Red light doesn't come on there is a problem with the diode trio gone out. So that wire and that light is important for the health of your alt..

So, if you plan on cutting wire and shoving it back into the bundle like you mentioned above, label it, or how ever many wires there are, then shove it into the bundle. That way if you ever want to use that wire again you can find it. I've got a lot of unraveling to do before I find it I'm sure.