CJ7 Temp Gauge

graydragon2

New member
My temp gauge is not even making it to the green line on the gauge. I checked the ohms and they are jumping around. Any ideas what it could be or what I could check. The reading is bouncing from about 85 to 150 ohms. The engine is getting warm but is not overheating.
 

Army_Vet

Banned
My temp gauge is not even making it to the green line on the gauge. I checked the ohms and they are jumping around. Any ideas what it could be or what I could check. The reading is bouncing from about 85 to 150 ohms. The engine is getting warm but is not overheating.

With the ignition on motor off, take the lead wire off the temp sensor. Ground it to the engine block, If the gauge tack's out to max and stays there. the problem is in the sensor. if it doesn't move there is an open in the circuitry, or the gauge itself.
 

graydragon2

New member
I did a test on my sending unit and it gave me a neg. ohms reading of -130. I grounded the wire to the gauge and the gauge went to hot. If the sending unit is bad would it give a negative ohms reading and if this isn't my problem what should i check next.
 

Army_Vet

Banned
I did a test on my sending unit and it gave me a neg. ohms reading of -130. I grounded the wire to the gauge and the gauge went to hot. If the sending unit is bad would it give a negative ohms reading and if this isn't my problem what should i check next.

With the info you gave me in the 2 posts, assuming you tested things the way I would, I would change the sending unit. Be careful how you seal it. it needs to hold the water in, and yet provide a good ground. I would use the liquid pipe dope, not the tape. Just my opinion
 

graydragon2

New member
I actually did some more testing on this before I ordered the sensor and cleaned it good with a wire brush and cleaned inside the plug good and it now is getting up to the green. I think it may have just been rusted up some and not making a good connection. As far as the meter goes, I think the battery is dying in it.
 

Army_Vet

Banned
I actually did some more testing on this before I ordered the sensor and cleaned it good with a wire brush and cleaned inside the plug good and it now is getting up to the green. I think it may have just been rusted up some and not making a good connection. As far as the meter goes, I think the battery is dying in it.

Well good that you found it. Thats why I said be careful on the instal, because it needs to ground well. I didn't even think to check it for corrosion. Its been a while since I worked on old jeeps.

Glad it worked out for you!
 
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