Temp Gauge maxed out, engine cold

[Corpse]

Ok, so ive got an 1983 K5 blazer 6.2L C code, long story short, my temp gauge is maxed out as soon as i put the key to the on position. when i switched out the glowplugs i noiticed an extra green wire in the same area as the glowplug wires.

service manual says that the temp switch/sender has a green wire attached to it that runs along with the green glowplug wires

so i took a voltage reading of these wires on the driver side bank thinking maybe i plugged the glowplug wire onto the temp swticth or vice versa

all three wires come back with a 10V reading... from my experieince as a boat technician, a sender wire should have no voltage, just read a certain amount of resistance.

now im sitting here wondering what im missing

[Liftgate]

A sender wire will have voltage. The sending unit varies the resistance to ground. Sounds like you have a the wiring wrong. Pull all wires off the glow plugs and temp sending unit on the driver's side and see what happens when you turn the key on. Your temp sending unit could be bad also or there is a short to ground with the sender wire. Those wires are easy to mix up! Hope this helps. Good luck.

[Corpse]

thanks for the help, i figured it out.

[Corpse]

so what I've learned, if the sender wire that attaches to the temp sender is not connected the temp gauge maxes out at hot.

hope that helps out

[Liftgate]

My coolant temperature circuit has been working fine. No problems. I have gauges, no idiot lights. I have an 84 suburban. I just checked this. With the temp. sending unit wire disconnected, the gauge shows cold, all the way to the left on the gauge. When I shorted the temp. sending unit wire to ground, the gauge showed hot, all the way to the right. If yours is different, you might have the wrong wire or there is a short with that wire. Make sure you have the right wire. It is a smaller, thinner wire than the glow plug wires. Get it going! ;)