The stock radiator low coolent level warning system light doesn't come on.

[Bob Dunahugh]

My dash warning light didn't come on. When I lowered the radiator level to test the coolant level warning system. So how do you test the sensor, light, and the small printed circuit board under the dash? Bob Dunahugh 78 Royale

 

[johnny]

It works by passing a slight current through the coolant via the probe on the passenger side. Disconnecting the wire to the probe should cause the
level alarm to light. Grounding the wire should cause the light to go out. It works much the same as the level sensors for the water tanks.
If it doesn't light and extinguish as it should, Check wires for continuity and clean connections. Make sure the circuit card is supplied 12V when
the key is on, is grounded,, is connected to the light bulb, and is connected to the sense wire. If it still doesn't work, and the bulb tests good,
suspect the circuit card. If I have a schematic for it, I can make it work.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

 

[jerry burt]

On mine, the printed traces on the board and the connections on the bulb sockets were corroded. Cleaned them and viola. Of course,your mileage may
vary.
--
Patti & Jerry Burt
73 Gmc 26' Canyon Lands -
77 Palm Beach
Members: FMCA - GMCMI - GMCWS - Pacific Cruisers - 49ers

 

[chris tyler]

Is it coolant level or coolant percentege on the GMC? ON a couple of contemprary GM vehicles I owned, it was apparantly percentege and didnt work if
the percentage of antifreeze was lower than some point. I was running straight water with pump lube- on constantly. Someone told me about it and later
when running 50-50 mix it worked fine.

THe sensor Im refering to was on the radiator. Not on the coolant overflow.
--
76 Glenbrook

 

[johnny]

The OEM sensor is located in the passenger side radiator tank about a fourth of the way down. It consists of a simple wire probe glued into a hollow
fitting using what looked like some sort of epoxy. GM refers to it as a coolant LEVEL indicator. If you wanted to play around with it, you could
submerge the probe in different concentrations of coolant and distilled water, and measure the resistance of each. From this you could derive a
percentage display if you wanted. I'd really rather know the water's low while traveling. I suspect any corrosion would throw off a percentage
measuring system, since the corrosion products will ionize and change the conductivity of the coolant.
The above being said, it ain't a replacement for getting your finger wet each morning before you take off, and checking for drips under the coach,.

-johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased