56 Chevy 210 car temp gauge works when it wants to. Tried grounding temp wire and gauge won't peck to hot. Grounded sender terminal from under dash still nothing. Checked to be sure I have power when key is on, good. This is the closest schematic found but it's not GM, it's Mopar. Do GM unit work using the same principle? I think it's losing grounding of gauge body when it stops working.
Rare to find one working correctly. Watch the evil bay and you might find an NOS one. Be sure is for a 56 as you already know
works differently from Mopars. They tend to develop intermittent breaks in the windings or connections. Sometimes, whacking the dash will get it to work again? did on one that I had. Good luck....
Thanks Jim. I was pissed after correcting wiring under the dash thinking I did something wrong at first even though I pretested leads for continuity. Explains why car had aftermarket gauges in it when purchased.
Paragon Corvette has the closest sender to OE. I had problems with all I tried, but the one they offered did the trick.
You probably need a new gauge Johnny . I'm sure you realize the aftermarket stuff is mostly crap. I may have one in my stash. The local gauge shop I use is also very talented at gauge repair. PM me .
Not a sender unit issue. When car was purchased it had no oil light nor temp gauge that worked. While doing engine swap I pull interior dash apart for repairs among other things The sad part is someone put a new under dash harness and butchered it in a few area's and wires that should have went out to engine compartment were inside taped over with ends still on.
Thanks, I have a spare from my 56. I started this thread to see if gauge also needs to rely on being grounded that would connect internally like what I posted above. I know that fuel gauge is like that but no idea about temp.
Sometimes just to be sure I run a ground wire from the back of the cluster to the dash , as not to rely on the bezel mounting screws.
Your schematic is for a thermal/electric gauge. Your 56 should have a balanced coil gauge. It has two coils inside the gauge, the gauge armature is balanced between the differing magnetic fields of the two coils. One coil is connected to power and ground. The other is connected to the same power but the other end of the coil is attached to the sending unit. Typically an open circuit on the sender coil results in a full scale reading and a grounded circuit on the sender coil gives you a low scale reading.
Yup. The 55 Chevy manual shows the gauge circuit for the gas gauge, in 56 the new electric temp gauge worked the same way.
Use a potentiometer as a substitute sender unit [if the gauge works fine, it is the sender unit] With the potentiometer you can read resistance across it at different gauge positions and then you can measure the resistance of the sender at different temps. If you change the thermostat temp of your engine and want to keep the gauge reading "normal". You can then add a resistor to the sender wire [either parallel, or in series] to tune the position of the needle edit: Also note the 56 sender unit is a 1 year only sender [55's were mechanical, and 57 and newer had different resistance values]
The sending unit has to have a real good ground contact with the intake or head. I've run into a couple that either had so much Teflon tape or on a cast iron engine so much paint on the threads that it wasn't grounding. On my OT Chevy truck I had to hunt down and find a Delco sending unit. The temp was way off with the old sender. It was actually low Looking at a Delco temp sending unit on Rock Auto that is for a 56 with a gauge it says the working range is between 100 and 120 More Information for ACDELCO 2131140 (rockauto.com)
Just thinking, there isn't an off chance that you bought a sending unit to fit the engine rather than the car and ended up with one for a light or that has a rating different than the 56?
The Standard Motor Parts TS-6 sender usually works with the 56-up gauges. I've never encountered a sender ground issue, but I sure hear a lot of stories about them. If you have an intermittent problem, it's highly likely it's in the gauge. There is a lot of fine wire in there, and several places where things need to make contact, but corrosion is likely at those points. The sender is really dead simple, compared to the gauge.
The very first thing I checked was sender grounding because upon first fire up temp gauge did not work. Only upon second day of taking the car out did I notice the gauge was working. Works a few day's then stops repeat. Still have back up mechanical gauge for back up. As for correct sender, yes it's the correct unit that works with 56 car temp gauge. Before Tear Down After Swap
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