Hot Air Only, Temperature Gauge Reads 0

[rockerZ71]

Hey everyone,

 

I drive a 2004 Silverado 4x4, 5.3 liter engine. Last week I had the transfer case replaced. Noticed over the weekend it was leaking a little so I had it re-done and picked it back up this morning. Drove a mile to work just fine and it sat all day. I didn't start it up at the shop, it was running when they handed it over to me.

 

When I got off work my battery was dead. I went back to that shop and got a battery starter and used it to jump the truck. Took it back over there and got the battery replaced (cheaper than what Advance would give me one for). All went well until...

 

I noticed shortly after starting my drive home that I could only get the vents to blow hot air. Its a relatively cool night here in Atlanta but the air coming at me was hot, even if I turned up the AC. My first thought was it was overheating, but the gauge read 210 (normal).

 

A little while later, the gauge dropped all the way to 0 (160 actually). No warning lights came on or anything, the gauge just stopped reading. Still could only get hot air. I turned up the heat all the way and dove home where I am now. I opened up the hood and nothing was steaming and it doesn't feel excessively hot under there to me, but I'm no mechanic. Coolant reservoir looks OK.

 

Any thoughts?

 

Whatever advice I can get here would be much appreciated

[[email protected]]

Is it possible it's low on water and water is not touching the actual temp sensor in the head, thus not getting a temp?

[rockerZ71]

Is it possible it's low on water and water is not touching the actual temp sensor in the head, thus not getting a temp?

 

 

Sure I guess. Just seems like it could have something to do with replacing the battery, I'm trying to correlate the things that went wrong at once.

 

How does the temp sensor affect the air that is blown through the vents into the cab?

[[email protected]]

Well, you said your reservoir was empty, I'd start by filling it up. And as far as the CTS affecting the air vent temp, I really don't know, unless disconnecting the battery reset you blend door actuators and they need to be calibrated again, pretty common thing with these trucks I hear.

[rockerZ71]

Well, you said your reservoir was empty, I'd start by filling it up. And as far as the CTS affecting the air vent temp, I really don't know, unless disconnecting the battery reset you blend door actuators and they need to be calibrated again, pretty common thing with these trucks I hear.

 

 

I'm embarassed to say I was wrong about the reservoir being empty. Turns out the way to check that is not to look down where you open it up. Its full.

[rockerZ71]

I just went and cranked it up again and initially the temp gauge climbed a few degrees and then settled right back down to no reading. I turned the vent temp all the way down and after a few seconds cool air (ambient temp) started blowing. Turned on AC and that worked too. Still no temperature reading from the gauge worries me

[[email protected]]

The only thing I know to tell you is to go under the hood and while the key is on and unplug the CTS read the gauge then put a paperclip in the connector to the CTS and read the gauge, if there's no change then something is wrong somewhere in the computer. If it changes, the CTS is bad.

[rockerZ71]

The only thing I know to tell you is to go under the hood and while the key is on and unplug the CTS read the gauge then put a paperclip in the connector to the CTS and read the gauge, if there's no change then something is wrong somewhere in the computer. If it changes, the CTS is bad.

 

 

I was too lazy to do the paper clip trick, plus auto zone is 2 miles away and was about to close. I had him scan it and it had code P0116 which was the coolant temp sensor. I went ahead and bought one and I guess I will put it in tonight and see what happens. Air temp control worked fine on the drive to and from there.

 

Assuming this fixes my problem, I'd really like to know how the air temp in the cab and that coolant temp sensor are related

 

Thanks for all the replies

[[email protected]]

Just let us know how the CTS works out for you.

[rockerZ71]

Just let us know how the CTS works out for you.

 

 

apparently I'm supposed to drain the coolant to do this. I may not be doing this tonight

[[email protected]]

Nope, just take the old one out and out the new one in quick and you won't loose hardly any coolant. I've never seen someone drain coolant just to replace a CTS.

[rockerZ71]

Nope, just take the old one out and out the new one in quick and you won't loose hardly any coolant. I've never seen someone drain coolant just to replace a CTS.

 

 

If you say so, I reckon I'll give it a try

[txab]

Anytime you disconnect the battery or remove the HVAC fuses, the HVAC will go through a recalibration. Sounds like that's what your ac problem was. Usually only takes one key cycle to complete the calibration. Sometimes it may take longer.

 

CTS replacement, Have the new ready to install. Remove the old one and install the new one quickly. You shouldn't loose much coolant. Just make sure you replace what ever you lost

[rockerZ71]

Anytime you disconnect the battery or remove the HVAC fuses, the HVAC will go through a recalibration. Sounds like that's what your ac problem was. Usually only takes one key cycle to complete the calibration. Sometimes it may take longer.

 

CTS replacement, Have the new ready to install. Remove the old one and install the new one quickly. You shouldn't loose much coolant. Just make sure you replace what ever you lost

 

 

Thanks, that makes me feel a little better about it. I didn't realize the computer was involved there but I'm not surprised.

 

Changing out that sensor is going to have to wait until the morning (I just had to drive it, and its late), but I will let yall know how it turns out

 

'preciate the help both of you

[[email protected]]

Once again just let us know how the cookie crumbles.