Hey guys,

I have a 2011 Hyundai Accent that is my work commuter. Once the engine warms up I get a coolant temp light on the dash... I can get it to go on and off with using the blower motor switch.. fan on high and couple minutes light goes off, light on with blower off.

I have read comments on this forum as well as others and checked coolant level ( which is good) I have check rad fan relay and fuse both good. I have replaced thermostat and coolant temp sensor. I have also checked the head temp the best I could with a laser thermometer and it never exceeds about 80-85 degrees c and that’s with light on. I have also just replaced the rad cap.
I am not sure where to go from here and hopefully someone has a solution. Is this a coolant flow issue? Maybe a coolant flush or is this more catastrophic like a bad head gasket ? I will also note that it has not been burning a drop of oil or coolant that I can notice.

 

We don't know at this time if it is an electrical or actually a temp problem.
If the light goes off instantly after you turn the blower on , it is most likely an electrical problem. If it takes a short while after the blower is turned on , then it could mean the heater is removing some of the heat from the coolant. Knowing which condition applies could help point to the problem.

 

This is where it is kind of weird... when I first start driving and the engine is cool the light will come on instantly when I turn blower on .... as I drive further the light will then stay on with blower off and once blower is selected on it will come turn off after 15-30 secs and about the same 15-30 secs for the light to turn back on after blower is selected off. If I continue to drive the light then will turn on and stay on solid which leads me to a temp problem. I did consider a charging system problem the alternator is fairly new but the battery may be getting a little tired on cold morning starts or multiple starts it is slow to crank.

 

It pays to pay attention to what the system is trying to tell you and you are noticing this..
A suggestion, some places will check the battery and charging system , hoping to sell you what they think will solve the problem.And do this at no or very little charge.
If the battery is original, it is due for replacement. Before offering anything else, it is important to have a good battery and properly functioning charging system.Can we do this?

 

Thanks for the reply. As I said I was questioning the battery anyways as it seems to get up to around 11.7volts and the alternator is putting out 13-14. The battery sure isn’t original but it is atleast 5 years old. I will get a battery and see what happens. These covid restrictions aren’t making things easy to get stuff accomplished.

 

Just please be careful, because anything with the vehicle can be replaced, but you might be a little more difficult to replace.

When and where are you getting that battery reading? It is definitely too low.

You will notice a different reading if you measure the system voltage at the battery as compared to at the alternator output terminal. A slight variation is normal, but any larger amount is something that would require further diagnosis. Are the battery cable connections at the battery clean and tight?

 

Well I tested the battery and alternator output... the battery was not in great shape so it has now been replaced.

still getting a coolant temp light once car gets warmed up. I am still thinking it might be something electrical as I cruise down the highway the light will be out.. if I turn on something electrical it will turn the light on and back off.. for example I turn on wipers light comes on. Wipers off count to 5 and light goes back off. And this happens with blower,turn signal, and other electrical draw. But wont do it in the morning when I first start driving for the first 15 min or so of driving.

any ideas ???

 

Funny thing, those loose electrons will take any path to get home, and it would seem they are using your temp light to do this.
A good part of the time those electrons would normally go to ground , but if the normal path is not available they seek an alternate path. With this in mind it might be a good idea to check, (CLEAN) and make sure all the ground connections are clean and tight. You might start with all the ground wires on the engine, then those that connect the sheet metal to a good ground..Let us know how you make out with this, thanks.