Topic: Water temp gage

[1FSTLS1]

My water temp gage was not working when I got the car the joker had some aftermarket one hooked up onder the dash all half a**.  Any way I took my gage cluster out to clean things up and noticed that the needle was not broken off but just 180d all the way to the bottom.  I blew some dust out and moved it up.  I have a feeling it is not going to work but in the mean time I want to test it.  The motor is not built so what kind of reading should the wire that goes to my temp sensor in the intake put out so I can test this bad boy? 

[brian c]

If memory serves....if you put 12+ to the + side and then leave the sending wire dangling in the breeze you should get the needle to swing to the left. Then if you ground the sending wire you should get full swing to the right.

Although I might have those reversed... has happened before. In any event, dangling will cause it to swing in one direction and then grounding the sending wire will cause it to swing in the other.

[ta78w72]

It's easy to test the water temp gauge if it's in the car.  Brian has the process right.  Disconnect the green wire to the sender (in the head by number 1 cylinder).  Ground the wire and with the key on the gauge should go all the way to the right.  Dangling with the key on causes the gauge to read all the way left.  Usually these gauges don't break.

If you have the cluster out of the car, check the plastic film circuit on the back for cracks.  Does the oil pressure gauge work?  Those gauges share the same 12 volt circuit.  If the test in the above paragraph doesn't cause the gauge to react, and the oil gauge doesn't work.....it's probably the 12 volt circuit on the back of the cluster.  That would be pin number 5 on the white cluster connector.  Check that pin for 12 volt too.  Check the circuit paths with an ohm meter.  After all those tests, if everything seems to be OK, then you can suspect your gauge.  My guess is the gauge is not the culprit.

[Rick]

Rich Keller should be reading this also -- OUT THERE, RICH?

[sCI]

HAHAHAHAHAHA, yeah I gues we all got temp gauge prblems, although, I though rich's car was restored??

Well anyways, hey guys, have you ever heard of this, because this is whats happening to me. The gauge works, but lets say I unplug it form the head, ground it, replug it and it warmed up reads the little line in the middle of 100, and 220(I have a 75' 400), but when I turn it off after running it maybe twice, it guage progressivly doesn't go back down to cold?? the gauge will go halfway between the littlin it is normally on, and 100, so whan the car warms up, instead of the needle on that little line, it is a litle over halfway between the little line and 220....I have let it go to the point of being halfway between 220 and the opposite little point. Tha wierdest thing is, is that al I have to do is unplug the wire at the sender, adn ground it, then replug it and it is sort of like reseting ir, and that whole preccess starts again?? ??

What could it be now( these stupid gauges are giving me so much trouble).

Thank you very much.

[ta78w72]

That particular condition sounds like a bad sender to me.  But go through the test above and see if the gauge responds correctly.  If so, replace the sender.

[rkellerjr]

Rich Keller should be reading this also -- OUT THERE, RICH?

Thanks Rick, I PM'ed Mr. ta78w72, he's on the case

[ta78w72]

Rich Keller should be reading this also -- OUT THERE, RICH?

Thanks Rick, I PM'ed Mr. ta78w72, he's on the case

But I should be working! LOL

[Rick]

We won't tell!

[sCI]

Well, I went to go check and When I turned the key on with it still plugged in(hadn't messed with it yet) it went to that line between the 100 and 220(i'll call that line #1). However, when I unpluged it went nowhere.

here is antoher thing to condider, when I took out the cluster I added an auxillary wire to the nut for the temp gauge, cause I thought maybe I could strait wire the gauge nut to the sender for whatever reasons. This wire has had wierd effects on the gauge. what do you think I should do with that wire, it doesn't seem to be helping me.

Well, after i grounded the aux wire it went to the right, and now under no circumstances will the gauge move, nomater where I ground it, which wire, or what I plug it into, The gauge won't move.

From day 1 I 've been thinkin that it is not the sender, but either the gauge or the wiring of the car.

What can I try next? should I try that gauge testing guide now ta78w72, or is there something ells possible wrong?

Thank you very much.

Oh, and 1FSTLS1, did you ever solve your issue

[ta78w72]

I'm not sure what wire you added or exactly where you added it, but you shouldn't need it.  I'd take it off.  Then go through the sender ground/hanging test again and see if you get the gauge to react.  Does the oil pressure gauge work?

If the gauge doesn't react, then pull the cluster and check for 12 volt at pin number five with  the key on.

Check the sender wire for integrity by connecting your ohm meter.  One lead should be connected to pin 13 of the white cluster connector and the other lead should be connected to the disconnected sender lead at the sender.

If both those tests are OK, check both circuit paths on the plastic film circuit, the ones from pin 5 and pin 13 for breaks.  Check them with a magnifying glass as well as your ohm meter.

If those tests check out OK, replace the gauge.  Make sure you get the right gauge for your car because they changed the resistance spec in 1980.

[sCI]

I just added a piece of wire a foot long to the little bolt for the tepm gauge coming out of the circut in the back of the cluster. Unfortunately, the oil gauge bounces around but doesn't "work". so it is of no use.

Where can I get an ohm meter and how much are they?

Will an aftermarket gauge work?

Thank you for the help(for the 5th time).

[ta78w72]

Get a  multi meter.  They can run from almost nothing for a cheap one to a few hundred dollars for a really nice one.  I have a 30 year old cheap one.

[Rick]

Russ is correct -- get a multimeter, and then you can measure AC/DC volts, resistance, and small currents if needed.  Radio Shack can fix you up as can most larger hardware stores and the home supply outlets (Lowes, Home Depot, etc.).

[sCI]

ook thanks, I'll pick one up in a day or two.

Also, will this multimeter test my guages too. or was that another tool use on the gauge testing pdf file I got?

Thank you.