temp gauge

[WarMonger]

How can I test my temp gauge to see if it is working? I don't know if its the gauge or sending unit, but it never moves.

[nzc10]

With the key on pull the temp gauge wire off the sender and earth it out on the engine check if the gauge is full over to the hot side on the needle if so the gauge is ok if the needle on the gauge is stuck on cold the gauge could be stuffed as long there's no break in the wiring

[WarMonger]

Originally Posted by nzc10

With the key on pull the temp gauge wire off the sender and earth it out on the engine check if the gauge is full over to the hot side on the needle if so the gauge is ok if the needle on the gauge is stuck on cold the gauge could be stuffed as long there's no break in the wiring

Thank you.

[nzc10]

No worries hope you can sort it out, nice to see you like 2 wheels as well

[centuryhouse]

May I add one question? It seems wasteful to start an entire new thread for this one question...

Can anyone advise on what wires should be connected to the temp gauage? The green one coming from the sender on the block, but what else? Is there anything else that should be plugged in to the back of the temp gauge?

[WarMonger]

Should just be the green wire.

[centuryhouse]

Originally Posted by WarMonger

Should just be the green wire.

No power? Or is the power straight from being connected to the board?

[Jurassic-1]

It is a ground wire there is no power at the sender. You can ground it and the gauge will move up.

[centuryhouse]

Originally Posted by Jurassic-1

It is a ground wire there is no power at the sender. You can ground it and the gauge will move up.

Sorry, I'm asking about the gauge. If a ground wire goes to it, I assume a power wire must as well. But my gauge has no wires going to it other than the green sender wire.

[Sklptrljay]

Originally Posted by centuryhouse

Sorry, I'm asking about the gauge. If a ground wire goes to it, I assume a power wire must as well. But my gauge has no wires going to it other than the green sender wire.

The gauge is reading resistance between the sender and the ground (engine). That is why when you touch the wire at the sender directly to the engine, the gauge should read full hot, because it has no resistance.

Yes, the gauge itself is wired to the printed circuit. The green wire (gauge terminal) goes to the sender and the other gauge terminal is to 12v.

[VetteVet]

Here's a dash gauge wiring layout. The purple lines feed the fuel gauge and the temp gauge from terminal 3 on the cluster plug. The wire from the temp sender runs from the sender to the no.6 terminal on the cluster plug. The green line feeds the gauge. There are no wires to the gauges.

[centuryhouse]

Originally Posted by VetteVet

There are no wires to the gauges.

Hmm. If there are no wires to the gauge, why are there four posts with nuts on the back of the temp gauge?

[VetteVet]

Originally Posted by centuryhouse

Hmm. If there are no wires to the gauge, why are there four posts with nuts on the back of the temp gauge?

Those are for connecting a resistor between the needle coils inside the gauge to prevent them from burning out by the 12 volts applied.

[centuryhouse]

But the sending unit wire doesn't connect to anything? Does it connect to the gauge through the circuit board via pin #6?

If so, that's what I've been missing. I was looking for the sender wire to be connecting to the post.

[Davidf]

Yes, per the wire diagram (post #11) the sending wire connects to the cluster wire connector (pin #6) then to the gauge via the printed circuit "board". Make sure the printed circuit trace is not broken (either or both sending and power).

[centuryhouse]

Originally Posted by Davidf

Yes, per the wire diagram (post #11) the sending wire connects to the cluster wire connector (pin #6) then to the gauge via the printed circuit "board". Make sure the printed circuit trace is not broken (either or both sending and power).

Good info, thanks! All looks good, and I just did the test that was mentioned of touching the sending unit wire to the block - when I did it pegged the Temp gauge needle, so I now know the connections are all good.

[moon]

SO, when I touch my properly grounded test light to the #3 purple feed pin on the connector, the test light should go on.... right? And if so; in what ignition key position ---> ignition on? ... accessory on?... both?.. with engine running on or off?

Both my temp gauge (new) & gas (original) don't work & appear to be "dead" & I've been messing with this for toooo long....

[Davidf]

Yes, it seems that #3 would have power with the key in the run position only. But, I would need to check my factory wire diagram which is not handy at the moment. If you don't get 12v at the wire pigtail contact, then this would explain a non function temp and fuel gauge as they both get power from terminal #3.

[VetteVet]

The pink ignition wire from the key switch runs to a junction with three other wires as shown in the first diagram. It is the 5th wire from the top. These diagrams are for the charging light cluster but the pink wire are the same. On the cluster plug for the charging light the pink wire runs to terminal 7.








It runs to the fuse panel to power the cluster pnl fuse.

[ATTACH][/ATTACH]


From the fuse panel it runs to the cluster plug to terminal 3 and becomes hot when the key is turned on.

[WIDESIDE72]

I went through all of the trials and tribulations of trying to get my temp gauge working a while back. Turns out that none of the over the counter parts store sending units have the right resistance. I bought one of these and now it works like a champ.
http://www.ebay.com/itm/NEW-gauge-te...638874&vxp=mtr

[centuryhouse]

Originally Posted by WIDESIDE72

I bought one of these and now it works like a champ.
http://www.ebay.com/itm/NEW-gauge-te...638874&vxp=mtr

That isn't the connector type my temp sender has. What does the other end of this (the wire end that connects to this sender) look like?

[WIDESIDE72]

Originally Posted by centuryhouse

That isn't the connector type my temp sender has. What does the other end of this (the wire end that connects to this sender) look like?

The wiring connector is a spade connector. It slides on at a 90 degree andle instead of straight on lie you are probably used to seeing.

[centuryhouse]

Originally Posted by WIDESIDE72

The wiring connector is a spade connector. It slides on at a 90 degree andle instead of straight on lie you are probably used to seeing.

Excellent, thanks. I've been having problems finding an appropriate replacement (with the smaller 3/8" threading) that has a straight tab type like mine. It sounds like I could use this type and just replace the wire end with a 'spade' type connector.

[moon]

Thank you for your help!

I checked the plug terminal (disconnected from the panel) with my test light & do NOT get power at the #3 pin. But I DO get power at the cluster pin, when the headlight switch is pulled on.

I'm having difficulty following the schematics: I'm not seeing the "junction" you mentioned where the pink wire & two others run to. Also a bit confused with pink wire vs purple wire.

I have a '70 C10 CST. The #3 wire in my terminal is pink(ish.) All the wires coming from the ignition switch are bundled/taped together and lead up, over & down to the top of my fuse box, appearing to run down behind it. The pink wire coming out of the connector on the firewall side of the fuse box runs to the starter.

If The pink wire powers the cluster lights (as it should) but is not powering the #3 pin, where should I look to find the break?

Also: I don't know if this is related (doubtful?) but my altimeter reads backwards --> When the headlights are on without the engine running the needles leans right to "C." When I start the engine running, the needle leans left to "D" then after eventually returns to the center line.

Here are some shots of what I'm dealing with:

IMG_0053 by moon, on Flickr

IMG_0051 by moon, on Flickr

IMG_0049 by moon, on Flickr

[Phildeez]

I'm in need of a little help on the subject too. My gauge only rises to the second line of the cold zone and fluctuates down and back up to the same point. I've tested my gauge by grounding it and it goes to hot. I've got a reading of 333 ohms after a it is warm and the gauge is still just off the first cold line. According to a resistance/temp chart it was right around 175-180 degrees. Any help would be appreciated.
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