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Eric Wettschreck

temp sensor

16 posts in this topic

I've been working on the wifes car and I'm feeling kinda dumb. She has a 93 grand am with the 3300. I'm looking and looking and looking and I can NOT find the temp sensor. Anyone out there have an idea where it is? It's not threaded into the radiator header and I can't find anything.

I'm looking for this sensor cuz the car will idle forever, and the fan doesn't come on. The temp gauge reads fairly cool but the upper hose is far from cool. The fan does not come on. So I want to test the sensor BUT I CAN'T FIND IT.

Anyone, anyone, anyone know where the darn thing is????

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Does the fan come on when you turn the AC on? It takes a long time for them to get hot to the point the fan kicks in. Is it boiling over or are you just concern that the gauge is not reading correctly?

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NO fan. Ever. I turn on ac and no fan. Idle for 40 minutes and no fan.

Gauge is reading cool. Upper hose is hot.

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When the AC compressor cycles the cooling fan should kick in. You may have a bad cooling fan.

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One more thing, if you can get to the connection at the fan. you can check for power and ground and if you can you could hook up a power wire and a ground wire to the fan the fan should run. It may run backwards if the wires are reversed but atleast you will know if it works.

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I would also go with the fan theory however there are a few things I would like to check. The first is to hook up the scan tool to see what the computer is actually seeing for engine temp. Normally these will run up to 220 degrees before the fans come on!

I wish I could remeber but I think this has two sensors (I'll check tomorrow) one for the guage and one for the computer which also controls the fans.

Don't forget to check fuses Obviously.

Deffinetely check to see if the fan has power and ground. I also like to run power and ground to make sure the fan doesn't work if I'm suspicious!

If it was the temp sensor I would think you would also notice some driveablity problems. Running ruff at Idle, Running rich, poor fuel economy, hard start up when warm, Etc. Way more like to be a fan or something in the fan cicuit.

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I jumped power to the fan and it no works. So i know there is a fan issue. No problem there. However, the gauge is still reading like maybe 140 at the most. I'm having a tough time believing that one. I'm still looking for a temp sender for the car. I can't find the darn thing anywhere.

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There is 2 sensors they are both under/behind the alt.

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Ewwwwwwww, nice and easy to get to.

Thanks.

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Are you sure its not a t-stat stuck open?

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Fairly positive. I don't have a scope to put it on to see actual temp, but the upper hose is hot. Also, even tho I'm fairly sure the temp gauge is not accurate, I do see it drop after a bit. My thinking is that the t-stat is working. However, I could be wrong on that one also. I had it idle here at work in the shop for a while and put a heat gun on the upper hose. Now I know this is not an accurate test but the heat gun was showing 180 degrees. That tells me the upper hose fluid is quite a bit hotter than that.

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Sounds low? Heres what I would do. From a cold start hold on to the upper hose. If it gradually starts to warm up as the car idles than its likely that the stat is open. If it all of a sudden gets hots after the car runs for 5-10 minutes than I would think the t-stat is fine.

Also you never mention anything about overheating. If the fans where not working and the t-stat was functioning normally than this vehicle should have started to over heat while it wa running in the shop. The gauge may have not shown it but you should have heard it trying to boil over.

Its nothing for these older GM to run around 220 degrees before the fans come on thats why it would be nice to see what the computer is seeing for engine temp. Also if the temp sensors are on the passeger side thats where the coolant ends up after it gets cooled of by the radiator. If the stat is stuck open than a continuous flow of cooler coolant would make its way to that area.

For less that 10 bucks I think I would put a stat in it before I did anything. Then I would concentrate on why the fan is not working. If you tried to jump it and it still did not work than I would guess that the fan motor itself is culprit.

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Something is happening, I'm just not too sure what. Overheating is absolutely possible. It's leaking/bubbling/boiling out the belch tank cap.

During lunch break I'll do the start and run and feel hose thing. I know for sure the fan is kaput so I'll be looking one of those up, also. Thanks for the input. I'll post what's happening after lunch break.

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What I know for sure is that I need to remove my head from my hinder. The fan works just fine, I had some fairly bad connections when I checked it out.

The T-stat is stuck open, thanks airjer.(I didn't even think of that one) The belch tank now has a new cap so it's no longer leaking.

One thing is still confusing to me, however. In the shop, running, with the AC on, the fan will not turn on and off. I was under the impression that when the AC compressor kicked in the fan was supposed to also. Any ideas what to look at with this one???

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Its a '93 GM car and you expect the A/c to work? grin.gif

Does the A/c compressor clutch actually engage when you turn on the a/c

Does the A/c work?

If the a/c is not working then the fan will never come on. It has something to do with high and low side pressure switches that help control the fans and fail safe the compressor. one possibility is that it is low on refridgerant, if this is the case than the system will not function and the fans will not come on.

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If the AC doesn't work, I really don't care. However, Ya its blowin all kinds of cold air. The clutch is engaging.

We never use AC so if it doesn't matter then I don't care.

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