Wiring diagram autozone

Sensor in the fill tank is probably bad .
LOW COOLANT
The IPC illuminates the LOW COOLANT indicator in the message center when the IPC detects a low coolant level condition from the PCM. The IPC receives a class 2 message from the PCM indicating the coolant level.
Coolant Level Control (If Equipped)
The engine cooling system contains an engine coolant level switch to alert the driver in the event of a coolant loss. The powertrain control module (PCM) sends out a coolant loss signal over the coolant level switch signal circuit. When the engine coolant level switch reads a low coolant level in the fill tank, the switch opens. The message center receives its power from engine wiring harness junction block on the battery positive voltage circuit. Ground is provided by the ground circuits via the body wiring harness junction block and the engine wiring harness junction block. The cluster receives the class 2 message from the PCM indicating Low Coolant and displays the LOW COOLANT LEVEL message on the driver information center (DIC).

Is the fill tank full ?

They are 2 ways to get this. An internet search using your year make and model car with the term fuel pump wiring or wiring diagram usually pulls up a collage of good diagrams. Or the autozone site has a help site at the bottom of its help page, There is a free part and a pay part, but free info will supply diagrams.

My info says upper engine, center, close to water outlet, for the coolant temp sensor.
If your not sure look up wiring diagram for that sensor, note the wire colors. Autozone.com has free wiring diagrams as well as bbbind.com

Check your relays. If it is not hung near the coolant fan, the relay should be in a Powerbox.

Go to the Autozone site and register your vehicle for free, then toggle to the help sections at the page bottom. There are both free and pay sites and both have wiring diagrams and fusebox layouts.

More like the sensor in the radiator is bad or stuck. Try tapping on it. It is in the passenger side tank of the radiator.

Did this someone check it or just tell you it needed a sensor?
On some vehicles there is' a sensor on the radiator but most are in the plastic recovery tank. Just fill the tank.The coolant needs to touch it for the light to go out.While the engine is cool add 50/50 mix to the coolant reservoir/recovery ,replace cover & start engine, Check light.
When fuel tank gauges start going wacky its because 1 of only a few things has happened.
The wiring to the fuel tank sending unit has become corroded or cut somehow, the plug has become loose or corroded.
The sending unit inside the tank was hit with a syphon hose or the tank took a good hit somehow. Maybe in an accident.
It is rare that the gauge has gone bad. Not to say it hasn't happened, it's just rare.

http://www.autozone.com/autozone/parts/Duralast-Sensor-Radiator-Coolant-Level/1999-Pontiac-Bonneville/_/N-jd6ghZ9pehj?counter=0&itemIdentifier=384818_0_0_

Are you sure you bled the cooling system properly?While filling the cooling system you need to make sure you have both bleeder screws out and fill the system til coolant comes out of both of them.Then install the bleeder screws and fill the system at the surge tank til about 1 inch below the surge tank neck.Put the heater controls to full hot and floor heat.Start the vehicle and open the outlet bleeder screw and leave it open til there is a solid stream of coolant coming out.them close the bleeder screw.Keep checking to see if the air is getting warm after about 5 minutes of run time.You have to repeat this procedure until the thermostat opens.If you have done this and is is still coming out the surge tank then you have to check it for a blown head gasket.Let me know what you find and good luck.

You can go to Autozone.com, and obtain a wiring diagram.
If they have the Repair Guide for the vehicle, they'll have the wiring diagram also.
[I checked, they have the wiring diagram for 1994 Chevrolet G20 3/4 ton Van's]

To view their Repair Guides you have to become a member. It's free to join, and you receive no spam mail.
I have suggested using AutoZone's Repair Guides on here, to those who need access to a free online repair guide. I joined to check it out before recommending, and have never received any spam mail, or have had any problems.

On the home page for AutoZone, go up to the right, and click on -Become a member.
You'll be directed to another page, where you are asked some personal information.
I gave my real email address of course, but that was it.
Write down the user name, and password you have chosen.
After you have filled it out go to the bottom, and click on Submit.
You are instantly a member, and do not have to wait for an email.

Go to the home page again, and this time click on Log In.
After you have logged in go to the upper Left, and click on - Manage My Vehicles
Now go down to the bottom right, and click on - Add a vehicle, in the orange rectangular button.

Click on the Year (1994), then you'll be directed to another page.
Click on the Model (Chevrolet)
Now scroll down, and click on - G20 3/4 ton Van
Click on the Engine size used.

You will now be on the main page.
To the left you will see the heading -
Select a Category

Scroll to the bottom, and click on - Vehicle Repair Guides

Go to the right, and click on - Chassis Electrical - in blue.
Under the white - Select a Chapter - heading to the left, scroll down, and click on - Wiring Diagrams

If you are not familiar with reading wiring diagrams, you may want to view the first two instructional diagrams,
How to read and interpret wiring, and Common wiring diagram symbols.

If your van has a gasoline engine, the wiring diagrams for the 1994 G20's start at the 27th diagram down.
(If I have counted correctly. It is the weekend)

To enlarge the diagram you can either click on Enlarge, or simply Left-click on the diagram itself.

Use the bars on the right side, and bottom to move the diagram around, so you view it fully.

sensor is part of the overflow tank. lift the tank up and unplug the plug on the bottom. you can just cut off the plug and splice the two wires together or take a bread tie and strip off the paper then jump out the plug. to replace the sensor you must buy a new tank.

Hi,

You can try verifying that the coolant level is up to the 'Fill hot' line. If the coolant level in the reservoir tank is sufficient yet the warning light lits up, then it could probably be a defective sensor. Normally, the coolant reservoir is the white plastic tank located behind the passenger side headlight. There' would be a black cap that says 'Engine Coolant Only' in yellow print and there is a wire harness connected to it. Where the wire ends in the tank is the sensor. You can try cleaning the sensor tip (that gets submerged in coolant) see if that helps. Otherwise a replacement might be in order.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

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