Temp gauge wiring

[Tectron]

80 CJ7.

Pulled the dash to do some cleanup and try to figure out why some of the gauges aren't working Mainly temp and oil, starting on the temp gauge, looking on the back of the gauge there is a light socket, 2 posts that are connected to each other via a half circle plate, and 1 wire that is not removable. Nothing is connected to the 2 posts, the single wire goes un-interrupted to the intake manifold and sensor, seems like it's missing a power source. Does it get it thru the light bulb circuit ?

[RiverandSand]

The half circle plate is a power shunt from the gas gauge which is supplying the power to the temp gauge. There is purple/w tracer wire somewhere in the loom with a round push on connector, that is the wire to the engine temp sensor and connects to the gauge.

[Tectron]

Originally Posted by RiverandSand The half circle plate is a power shunt from the gas gauge which is supplying the power to the temp gauge. There is purple/w tracer wire somewhere in the loom with a round push on connector, that is the wire to the engine temp sensor and connects to the gauge.

Yep, that's what I found out on the Temp sensor, that wire goes on top of the manifold near the thermostat housing. It looks like there are 2 gauges for the temp, the one mentioned above I think goes to the gauge in the speedo cluster and another located on the manifold goes to a aftermarket temp gauge that fits in where maybe a clock used to be. Id rather use the aftermarket one as it has numbers.

[Tectron]

Originally Posted by Tectron Yep, that's what I found out on the Temp sensor, that wire goes on top of the manifold near the thermostat housing. It looks like there are 2 gauges for the temp, the one mentioned above I think goes to the gauge in the speedo cluster and another located on the manifold goes to a aftermarket temp gauge that fits in where maybe a clock used to be. Id rather use the aftermarket one as it has numbers.

Now I am wondering, I should just try and get them both going again like th PO had them, sounds a little silly to have them both I guess but if the factory one in the speedo is good Ill hook it up.

[Tectron]

Originally Posted by Tectron Now I am wondering, I should just try and get them both going again like th PO had them, sounds a little silly to have them both I guess but if the factory one in the speedo is good Ill hook it up.

So I'm thinking that only a few members watch the forums, I could be wrong. I'm a new Jeeper ! your obligated to help me right ?

[shum8]

Originally Posted by Tectron So I'm thinking that only a few members watch the forums, I could be wrong. I'm a new Jeeper ! your obligated to help me right ?

No - we have quite a few members watching.... just not all at the same time. And some are like me - I have inoperable temp, fuel, and oil pressure gauges. Have an aftermarket oil pressure in now, and a new aftermarket water temp gauge yet to be installed. I’d love to get my originals going again, but haven’t pulled that off yet. M
All this to say while I am watching, I’d be of no help to you on this one.

John Strenk had a thread on Civilianjeep.com, but it appears to be no more. Try this - kinda technical, but easy to follow.

http://www.off-road.com/jeep/feature...mer-12863.html

That ought give some reading material till others chime in


I have no idea where I sent this from......

[RiverandSand]

Originally Posted by shum8 No - we have quite a few members watching.... just not all at the same time. And some are like me - I have inoperable temp, fuel, and oil pressure gauges. Have an aftermarket oil pressure in now, and a new aftermarket water temp gauge yet to be installed. I’d love to get my originals going again, but haven’t pulled that off yet. M All this to say while I am watching, I’d be of no help to you on this one. John Strenk had a thread on Civilianjeep.com, but it appears to be no more. Try this - kinda technical, but easy to follow. FIX THOSE GAUGES - A CJ7 Gauge Primer: Off-Road.com That ought give some reading material till others chime in I have no idea where I sent this from......

John is over on jeep forum in the cj section. He has a wealth of gauge knowledge. I have been following his temp gauge troubleshooting link, but still haven't got my stock one to work yet.

[cglax6]

Originally Posted by Tectron So I'm thinking that only a few members watch the forums, I could be wrong. I'm a new Jeeper ! your obligated to help me right ?

Nah, you're just in the same boat as most of us. My oil gauge is working, but temp isn't. I have an engine swap coming up and I plan to replace the dash with Speedhut gauges.

I'm no help here...

Ha!

[Tectron]

Another question:

The factory Temp gauge I thought was not working, but it kinda is, It goes up slowly as the engine warms up but goes all the way pegged to past Hot, engine does not appear to be overheating.

[cglax6]

Originally Posted by Tectron Another question: The factory Temp gauge I thought was not working, but it kinda is, It goes up slowly as the engine warms up but goes all the way pegged to past Hot, engine does not appear to be overheating.

Sending unit is either a replacement that doesn't match the resistance range of the temp gauge, or the sending unit is bad.

Get a voltmeter and check resistance between the S terminal and ground. Readings for stock temp sensor:
Cold, you should get a high or infinite reading.
Slightly warm - ~73ohms
Between bands - 36-13ohms
Hot - ~9ohms

To check the gauge itself, voltage from A terminal to ground should be somewhere around 5v. If it reads 12v, then the voltage regulator in the fuel gauge is shot. It won't read zero because your gauge is doing something. If it reads zero, call a priest.

My guess is your sender is aftermarket and not designed for the resistance range that the gauge wants to see...or you're running hot. I could be wrong, but there isn't much more that it could be...especially if you get the needle to move when the engine is running.