2009 Sierra 5.3 Coolant level sensor MIA???

[TheBigBadWolf]

I have a 2009 GMC Sierra with the 5.3. I am getting the "Coolant level low" message on my cluster. Went to check it out and coolant was a little low but not low

enough to trigger the message. I filled it up and the message stayed so I figured I'd test the sensor. Here in lies the problem. Unbolted the coolant bottle and there is a spot for a sensor but there is no hole for it nor are there any wires near the bottle. I've checked the sides of the radiator and the sensor isn't there either. Alldata doesn't give a location but in one section it says "Unplug the coolant level sensor from the bottom of the coolant reservoir". I went back and looked for a 2008 and Alldata doesn't say anything about a sensor or removal anywhere. Has anyone ran into this problem before and know where it is? I know some of the Corvettes used an algorithm for coolant level for some models but I'm really hoping that's not the case.

 

Thanks in advance. 

[dna9656]

Quite a mystery; you have to love it when a reputable source like all data doesn't reference a component the manufacturer says was used and there isn't any proof it was ever there. I'd call Chevy Customer service at 1 800 222 1020; maybe they can steer you in the right direction.

[TheBigBadWolf]

I'll give them a shout if tomorrow doesn't work out in my favor. Going to pull it in the shop and go all Doogie Howser on her.

[TheBigBadWolf]

So this was a doozie... So there still is no sign of any coolant temp sensor on this truck.

Apparently the HVAC control module went bad(the controls with the screen).

This truck has the dual climate feature where the passenger can change just their side. Apparently if it goes

bad it says the coolant level is low. Realllly big brain stuff by the engineers. I am told that if an HVAC control

module is swapped from a diesel to a gas vehicle it gives the same message, so that's fun. 

I hope if someone searches this to no end like I did they will stumble upon this thread.

 

[richard wysong]

Second post of that problem this week with the same solution. The other post listed the years that are affected

[av8tion4life]

I have the same issue on my 2008 and have been tracing wires and looking for hours before I came across this article. I had the hvac control replaced yesterday when the light came on but didn't think it would cause this. Thanks for the post. 

[Hex173t]

On my 2003 the low coolant sns is molded into the coolant tank shown in the OP's post. It's a reed switch with a donut like float with a magnet in it that operates the switch. I had the same message as op and my coolant level was fine.  Can't change the sensor, have to get a new tank.