Dash temperature hardly moves.

Tiny
PRINTSHOP52
  • MEMBER
  • 1996 BUICK CENTURY
  • 13,000 MILES
On my 1996 buick century, 3.1 engine, the dash temperature barely moves even when I know the coolant is hot, like during a long drive. I get heat in the car. Is it the sending unit? Dash gauge itself? The connections on the sending unit? I did pull off the top part of the unit, and sort of cleaned the prongs. And the dash gauge moved a little, very slowly up to the 1/4 mark. Is this the normal reading, or should it be higher? Ed
Saturday, November 19th, 2011 AT 10:16 PM

19 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
So the terminals for the sender were green or blue?Also do you have a multimeter?
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Saturday, November 19th, 2011 AT 10:26 PM
Tiny
SATURNTECH9
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Also you could have a thermostat stuck open?
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Saturday, November 19th, 2011 AT 10:27 PM
Tiny
RASMATAZ
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Check and test the thermostat and coolant temperature sensor-
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Saturday, November 19th, 2011 AT 10:29 PM
Tiny
SATURNTECH9
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What color are the wires going to the sensor you cleaned the terminals on?
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Saturday, November 19th, 2011 AT 10:34 PM
Tiny
PRINTSHOP52
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The wires are yellow, green, and black
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Sunday, November 20th, 2011 AT 12:18 PM
Tiny
SATURNTECH9
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Usually when the terminals of the coolant temp sensor corrod like that it means they have failed and are leaking coolant into the connector. Also are both upper and lower radiator hoses getting really hot?If you you cant clean up all the corrossion on the connector it will have to be replaced.
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Sunday, November 20th, 2011 AT 3:51 PM
Tiny
PRINTSHOP52
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The hoses are hot. How can I use a multimeter to test the wiring. Where would I connect it?
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Monday, November 21st, 2011 AT 3:23 PM
Tiny
SATURNTECH9
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Usually when the wires are the problem it will read dead cold on the gauge. The multimeter would be used to test the coolant temp sensor. So was the terminals for the coolant temp sensor blue or green?If so that is a dead give away the coolant temp sensor is bad and leaking coolant into the connector.I would suspect the sensor before the wires. When the engine is cold and like overnight cold unplug the coolant temp sensor and measure the resistance across the coolant temp sensors terminals let me know the outside temp and what the resistance was.
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Monday, November 21st, 2011 AT 5:17 PM
Tiny
PRINTSHOP52
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Forgive my ignorance. The terminals to be tested. Is it the one on the sensor itself that's connected to the block, or the plug that I pulled out? There are 3 on each. I assume the bottom two are the ones to check, and the separate one is the ground? Again, sorry for my dumb questions that most people know. Ed
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Tuesday, November 22nd, 2011 AT 1:09 PM
Tiny
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I only see two wires going to your coolant temp sensor a black wire and a yellow the sensor is top left side of the engine. Unplug the sensor and measure the ohms across the terminals of the sensor itself.
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Wednesday, November 23rd, 2011 AT 5:19 AM
Tiny
PRINTSHOP52
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We must be talking about 2 different sensors. My 96 Century has the 3.1 liter engine. I took a pic of it, kinda blurry, but there are 3 wires going into the sensor. Hard to see the black wire but it's next to the green wire. The yellow is on the top.

Anyhow, I guess I can just connect the black and the yellow ones? I got those alligator clips which might be difficult to do. But, I'll improvise. Ed
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Wednesday, November 23rd, 2011 AT 2:23 PM
Tiny
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My wire diagram shows two wires black and a yellow one I looked up the coolant temp sensor at auto zone and it also showed a two wire sensor. But I would measure where the black wire goes and the yellow wire goes to the terminals of the sensor.
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Wednesday, November 23rd, 2011 AT 11:38 PM
Tiny
PRINTSHOP52
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OK, With Thanksgiving activities, and cold weather, I'll have to put off checking the sensor for now. Ed
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Thursday, November 24th, 2011 AT 2:15 PM
Tiny
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Alright keep me posted.
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Thursday, November 24th, 2011 AT 3:19 PM
Tiny
PRINTSHOP52
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Wow, That other guy which seems like the same problem I have with the coolant sensor, really has a story to tell.

Well, Thanksgiving is over, weather was warm today. Went to car to check the sensor with multimeter. It was difficult to put the probes into the sensor. But I think I hit them, the yellow and the black prongs. Nothing registered on the meter.

So, I put the probes into the connector, and I got a reading of a little over 4 ohms. My mulimeter is a Micronta analogue no. 22-220A. I set it at X1K range. (I have no idea what it means). Maybe to be done with it, like the other gentlemen, I'll just replace the sensor. It seems simple enough, tho it looks kind of tight down there. I'm not familiar with using a multimeter. Ed
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Sunday, November 27th, 2011 AT 8:21 PM
Tiny
PRINTSHOP52
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A follow up query. I was web surfing this problem, and I came upon a site where the guy says to "remove wire from sender, hold it to a ground, and if dash gauge deflects full scale, gauge and wires are O.K" Is that possible? What wire would he be talking about, if the plug connector has female inserts? Ed
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Sunday, November 27th, 2011 AT 8:27 PM
Tiny
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The dark green one goes to the gauge so with the key in the run position engine off unplug the coolant sensor and ground the dark green wire the gauge should read all the way up on the temperture.
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Monday, November 28th, 2011 AT 7:14 PM
Tiny
PRINTSHOP52
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Yes, that's it. Grounded the green wire, and dash temp. Gauge went all the way up. So, I guess that means it's the sensor on the block that's not functioning properly.

When I get the time when weather is nicer, I'll change the sensor. Thank you for your time and patience with me. Ed
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Tuesday, November 29th, 2011 AT 4:10 PM
Tiny
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Your welcome thats what were here for.
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Tuesday, November 29th, 2011 AT 6:06 PM

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