Temperature Gauge

[wfl_colorado]

I have a none working temp gauge in my 73 240. I have tried to test is and either the gauge is bad of the wiring is bad.

What is the easiest way to remove the gauge? From the Haynes manual it appears that are a couple of nuts that hold it on from the backside. Do the gauges come out from the front of back of the dash? Also, can you really get to these gauges from the glove box or do you need hands the size of a 5yr old?Once the gauges is out I hope to do a continuity test on the wiring.

Tx,

Bill

[MikeW]

Those gauges come out from the back. While it's possible to go through the glovebox it's not easy to do without destroying the box. A better way is to remove the heater control panel. It's really not that difficult if you first remove the four control cables at their far ends.

[zhead240]

use electrical connector cleaner where the wire connects to the temp sensor first before tearing the dash apart.it's located by the thermostat. also i'm told the sensor is the ground for the wire. if threads are corrodid clean them,put antiseize gunk(not too much) on and be careful not to cross thread sensor when screwing back on. of coarse this is no help if guage is not working.

[Arne]

As a side note, never use teflon tape on the temp sender threads. It can insulate the sender from the ground, and then the gauge won't work at all.

[wfl_colorado]

Thanks guys. I did read a bit up on this through some old posts. I tried to test the gauge by grounding the wire off the sensor, but got no action on the gauge. This lead me to believe it was a wiring of gauge issue. I am hoping it is as simple as a loose wire since it appears that the PO appears to have tried to remove the gauge as it is a bit cockeyed.

[Arne]

The gauge wiring is pretty simple. One wire supplies power, the other goes to the sender to be grounded. So either the gauge itself is bad, the gauge isn't getting power, or the wire to the sender is bad. My first steps would be to ground the sender terminal directly at the back of the gauge to determine if the gauge works, and also to use a test lamp or volt meter to verify that the gauge is getting power.

[BuDavid]

Bill,

from your post, I understood that you are sure from that you short circuited the wire that is connecting the sensor to the gague..

I had the same problem, my gague was dead, I had a new sensor in my hand and wasn't sure that it is a sensor fault, I short circuited the wire to the flange mounting, it didn't work.. then gues what, I did it again but I scratched the tip of the wire harder to the flange and the gague showed a full scale reading!

make sure that u are connecting the wire to the body (or better to the (-) of the battery)..

there is a way that u can know if your cable (at least the part under the hood which u can see) is ok by penetrating a needle into the insulation of the wire and connect it to the (-) of the battery! if u get a reading then the part after is bad..

in worse case if u have to remove the gague, well, good be with u, coz both ways are hard, I did it through the glove box on my 280Z, well, I needed to remove the front panel and it wasn't that easy for me coz u might meet jammed screws or hardly tightened ones.. maybe to do it by removing the heater or what ever way it is is better, maybe more parts to remove, but at least safer for you parts..

be very carefull with the old parts pal..

ugood luck.

[wfl_colorado]

Thanks for all the info. I now have the dash torn appart and it appears the gauge isn't working. Where is the best place to find a replacement? Also, I didn't play w/ it too much but how does the light connect to the back of the gauge? In other words, how do I disconnect it?

Tx,

Bill

[beandip]

It should merely unplug from the wire loom and the bulb should just pop out of the holder. When you find a new gage , before you install it . Open it up and paint the inside of the ''can'' of the gage with white paint . You will see that the factory applied a little paint to reflect light , but if you take this a little farther and paint the rest , you will be amazed the difference. Don't' use silver , use white it is the better of the two. I imagine that there is a member willing to part with a temp gage. Otherwise go to the bone yard or watch craigslist or eBay. Gary:laugh:

[BuDavid]

beandip!

that white color tip sound great, but unfortunatelly I have all of my gagues back in thier places:( I would definitely paint them if I knew that!

but they wont glow more than the speedo meter gague and the tach.? it might be a bigger job then;)

[wfl_colorado]

Alright. I got the gauge out and finally noticed that the face of the gauge had been pushed back into the needle. I fixed that and reinstalled and now the amp gauge is the only one that appears to be functional! I didn't even touch the fuel/amp gauge so I am puzzled as to why the fuel part of the gauge would stop working. Man, when it rains it pours.

Question: There are 2 terminals on the back of the gauges w/ a jumper between them and a piece of shrink tubing over the "jumper". Does anyone know what this jumper is?

Again, thanks for all the help.

Bill