Temperature Gauge C1 not functioning

[Jim S.]

I had the gauges restored and all are working except the Temp. I am trying to determine what is wrong before I pull the gauge again and would appreciate any insight!

I have verified 12V at the gauge left terminal, verified continuity to the sender from the right terminal, measured 948 ohms of resistance @ 60 degrees from the sender terminal to the sender body and to the engine, measured 176 ohms of resistance across the two gauge terminals with no wiring harness wires connected. I tried to ground the sender wire to the engine (to see if the gauge would peg hot per other discussions) but the wire got hot very quickly with no needle movement. I tested the connection at the sensor and am getting a 12v reading, which does not sound right to my layman knowledge. All of this was done in a non-running mode by operating then ignition to ON.

If anyone can help resolve where the problem might be I would greatly appreciate it.

Thanks in advance, Jim

[John H.]

Re: Temperature Gauge C1 not functioning

the wire got hot very quickly with no needle movement. Thanks in advance, Jim

No needle movement would indicate a gauge problem. Was there needle movement when you disconnected the sender wire from the sending unit?

[Jim S.]

Re: Temperature Gauge C1 not functioning

John, no there is not any significant needle movement with the wire connected to the sender or not. The only movement to speak of of a small blip when the key is turned on! Does that suggest the gauge is bad? Could there be ground or power fault with that cluster (fuel & temp), although the fuel gauge appears to be registering correctly? Thanks, Jim

[John H.]

Re: Temperature Gauge C1 not functioning

Jim -

Sounds like a gauge issue to me - both gauges share the same 12V feed and the same ground reference.

[Richard M.]

Re: Temperature Gauge C1 not functioning

Jim,

I just ohmed out a 62 temp gauge(a spare assy I had on the shelf), and I get 30 ohms across the terminals. I get about 175 ohms from the inner terminal to case ground, and about 205 ohms from the outer terminal to case ground.

Check that the terminals at the gauge are not shorted to the case. Maybe the insulators shifted and you're getting a short. Try removing the wires, loosen then re-tighten the mounting nuts.

Worth a look see before you tear the cluster out again. It certainly is a painful task.

Rich

[Jim S.]

Re: Temperature Gauge C1 not functioning

John & Richard, thanks for the replies. I will test the ohms on the gauge to the case. I did take the mounting nuts loose and made sure that the gauge was centered in the mounting case holes, which I forget to mention in the original post.

Assuming that I end up pulling the gauge, does anyone have a suggestion for a trusted gauge shop? The gentleman that did my gauges has since retired, so I may be looking for a new vendor.

Thanks again, Jim

[Jim S.]

Re: Temperature Gauge C1 not functioning

I found and resolved the problem, finally! I removed the fuel & temp cluster, which is actually pretty easy if you remove the light switch first. A whole lot easier than removing the entire cluster!!!

Then I opened the case and found the sensor stud tab inside the gauge to be grounded to the main framework. It appeared that the stud might have been loose and in the restoration it was secured with some adhesive but either slipped or was put back together before the glue set and the tab made contact with the main framework.

After reassembling the gauges back into the case I have a reading of 29 ohms between the two studs, 176 ohms from the 12V terminal to the case and 203 ohms from the sensor stud to the case. After I reinstalled the fuel & temp cluster back in the car, the needle stays at the left (cold) with the sensor wire connected and disconnected. When I grounded the sensor wire the needle pegs full hot!!!!!

At this point I feel pretty certain that the temp gauge will work, which I will verify next week on a warmer day when I can have the garage door open and run the car! Now back to getting the final assembly chores completed!

Thanks again for the responses and info that got the better part of my curiosity to dig deeper and get this problem resolved!

[Richard M.]

Re: Temperature Gauge C1 not functioning

Great!!!!!!!!!!

It sounded like something was shorted in there. Glad you found it.

Rich