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Temperature Sending Unit Question(s)

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Old 02-08-2019, 12:29 PM
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Auggievf
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Default Temperature Sending Unit Question(s)

Why does the temperature sending unit have that weird disc connector and why does my dark green wire have a standard female wireconnector instead of the weird clip... I wish I would have paid more attention when I took it apart :- Simple connection how hard can it be.... *live and learn*

Did I get the right connector? It just slips over the disc with nothing securing it in place other than some friction?

Temp Sending Unit in the engine (between 1&3):

Clip I bought that I think is correct:


I have absolutely no idea how it was connected previously because the wire has this connector (standard female connector) and I didn't see any adapters in my parts:


Is there something that is supposed to go between the female connector and the new connector?
Old 02-08-2019, 12:48 PM
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jackson
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often helps to state year of vette ???

and is this for gauge or something else like a fan?

Last edited by jackson; 02-08-2019 at 12:50 PM.
Old 02-08-2019, 01:07 PM
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Auggievf
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Originally Posted by jackson
often helps to state year of vette ???

and is this for gauge or something else like a fan?
Oh sorry... I didnt think it mattered in this instance because I was just asking about the connection between the TSU and the wire but I have a "1974" chassis.... Everything else is Frankenstein's monster.... It's a crate engine so it's not really a stock 1974 engine, or interior, or engine components, or anything really I think....

As for the gauge or fan I'm pretty sure that the TSU just sends a signal through the wire to the light/gauge in the dash when the engine gets hot..... I'm not expert, my only source of knowledge is this forum and my AIM.

My confusion is because of the 'interesting' connection type on the TSU and the lack of an 'interesting' connector on the dark green wire... It just makes me wonder if I'm missing something between the two...

Last edited by Auggievf; 02-08-2019 at 01:16 PM.
Old 02-08-2019, 01:33 PM
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jackson
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The clip you bought appears to be correct for the sender in picture.

The sender appears correct for 74

Splice the white wire onto what exits at motor.

If you need color-correct for judging, suggest source such as Dr Rebuild.
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Old 02-08-2019, 01:36 PM
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jackson
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FYI --- some year C3 have TWO temp gauges... water & oil
Old 02-08-2019, 01:43 PM
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Auggievf
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Originally Posted by jackson
FYI --- some year C3 have TWO temp gauges... water & oil
Thanks. The only one I took off when I replaced my alternator a few weeks ago was the one on the drivers side. I think the other unit is on the opposite corner of the engine if I remember correctly....
Old 02-08-2019, 01:44 PM
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Originally Posted by Auggievf
Oh sorry... I didnt think it mattered in this instance because I was just asking about the connection between the TSU and the wire but I have a "1974" chassis.... Everything else is Frankenstein's monster.... It's a crate engine so it's not really a stock 1974 engine, or interior, or engine components, or anything really I think....

As for the gauge or fan I'm pretty sure that the TSU just sends a signal through the wire to the light/gauge in the dash when the engine gets hot..... I'm not expert, my only source of knowledge is this forum and my AIM.

My confusion is because of the 'interesting' connection type on the TSU and the lack of an 'interesting' connector on the dark green wire... It just makes me wonder if I'm missing something between the two...
Sorta. The sending unit sends electrons back to the gauge. The gauge sends "holes" to the sending unit, which sends them to the negative battery terminal through the engine and ground cables. Ultimately, it is the voltage potential in the battery, or from the alternator, that does all the sending. Confused? You can blame Ben Franklin for that.

I think the original 72-78 sending unit had a spade, as you would expect. As long as it connects, you should be good, but the sender may not be calibrated to the gauge.

The sender is a temp-dependent resistor, that completes a voltage divider circuit with a fixed resistor in the gauge. The gauge indirectly measures the resistance of the sender, and converts that into a needle position.

EDIT: Go drive your cool car! Use an IR thermometer to confirm what the gauge shows you.

Last edited by Bikespace; 02-08-2019 at 01:52 PM.
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Old 02-08-2019, 01:47 PM
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Originally Posted by jackson
The clip you bought appears to be correct for the sender in picture.

The sender appears correct for 74

Splice the white wire onto what exits at motor.

If you need color-correct for judging, suggest source such as Dr Rebuild.
Thanks. The lack of something between the TSU and the female clip just threw me for a loop and I wanted to make sure I wasnt missing something. Makes me wonder how it was connected before... Such a weird mystery....

No judging. Nothing is original or even close... I just want to drive my cool car. :-D

Last edited by Auggievf; 02-08-2019 at 01:48 PM.
Old 02-08-2019, 01:52 PM
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That still leaves my question about why the TSU in general has a 'non-standard' connector.

I haven't been around the block as many times as most of you but I helped tear apart the old engine and put the new crate in when I blew a rod and I don't recall any other electrical connection having that weird connection type. Nor have I seen any in other applications...

Perhaps it performs some specific function that a 'normal' connection type doesn't?

Last edited by Auggievf; 02-08-2019 at 01:52 PM.
Old 02-08-2019, 01:58 PM
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VDO TSUs can come with that connector. Are the gauges in your car stock? That connector provides a more positive connection than a simple spade connector, which can rattle loose, and as others seem to think, may actually be stock.

Last edited by Bikespace; 02-08-2019 at 01:59 PM.
Old 02-08-2019, 01:59 PM
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It's correct. Just jamb it on there. No special function.
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Old 02-08-2019, 02:01 PM
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Originally Posted by Bikespace
VDO TSUs can come with that connector. Are the gauges in your car stock? That connector provides a more positive connection than a simple spade connector, which can rattle loose, and as others seem to think, may actually be stock.
No clue. They look pretty new so probably not original and most likely reproductions.

Old 02-08-2019, 02:10 PM
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Originally Posted by Bikespace
Sorta. The sending unit sends electrons back to the gauge. The gauge sends "holes" to the sending unit, which sends them to the negative battery terminal through the engine and ground cables. Ultimately, it is the voltage potential in the battery, or from the alternator, that does all the sending. Confused? You can blame Ben Franklin for that.

I think the original 72-78 sending unit had a spade, as you would expect. As long as it connects, you should be good, but the sender may not be calibrated to the gauge.

The sender is a temp-dependent resistor, that completes a voltage divider circuit with a fixed resistor in the gauge. The gauge indirectly measures the resistance of the sender, and converts that into a needle position.

EDIT: Go drive your cool car! Use an IR thermometer to confirm what the gauge shows you.
hahahaha Thanks for the lesson. Damnit Ben.... I currently have my interior torn apart (https://www.corvetteforum.com/forums...-restomod.html) and was connecting up my new alternator when I noticed that the TSU wire was not connected.

It was previously connected (no clue how which is the real mystery) and I have not had any problems with it at all. It displayed the temperature just fine a few months ago before I tore my interior apart and replaced my alternator and will probably work just fine once connected.

I was just confused as to how the female spade connector on the wire was supposed to connect to the weird male connector on the TSU and wanted to make sure I wasn't missing something

Last edited by Auggievf; 02-08-2019 at 02:12 PM.
Old 02-08-2019, 02:21 PM
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Originally Posted by jackson
FYI --- some year C3 have TWO temp gauges... water & oil

what year had ''oil'' temp senders?
Old 02-08-2019, 02:31 PM
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Willcox sells them for '81-'89: https://willcoxcorvette.com/catalogs...erature+sender

Last edited by Auggievf; 02-08-2019 at 02:32 PM.
Old 02-08-2019, 05:03 PM
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Originally Posted by jackson
FYI --- some year C3 have TWO temp gauges... water & oil
Originally Posted by dmaxx3500
what year had ''oil'' temp senders?
https://www.corvetteforum.com/forums...-pressure.html
Old 02-09-2019, 11:24 PM
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To answer your question, the connector pictured is correct for the sending unit pictured.
No additional parts required.
When installed, the shaft under the disk of the sender should bottom out on the U shaped cutout of the connector.
The connector/wire will be perpendicular to the sender.
My 69’ has the exact same set-up.
Elm
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