69 z console gauges temp gauge problem

**scott s** · #1 10-12-2005, 05:04 AM

All the gauges work in my z but the temp gauge it just sits on the cold mark

When i touch the wire to ground it pegs on the (hot mark) like i think it should and i have tried several sending units but when warmed up it dosen,t move??? any suggestions or a diagnostic somewhere

Seattle Sam · #2 10-12-2005, 07:01 AM

You probably already thought of this, but make sure you have the sending unit for the guage, and not the one for the warning light.

-Sam

**69 Code51 Z** · #3 10-12-2005, 03:08 PM

Had a similar problem a few years ago. I have a friend that was a long time Ford mechanic and he had a tool from Snap On that checked gauges. It looked like a small box maybe 4" square with a rotary switch on top. Thew positions of the switch to the best of my memory was OPEN - 0 ohms - 75 ohms. He hook one lead to the lead that hooked to the sender and the other to a good ground. As he rotated the switch the gauge would go up and down. You have to make sure the sender is grounded to the head and that the engine is grounded. If you sender is wrapped with teflon tape or the threads in the heads have heavy paint that could be your problem. Hope this helps

**scott s** · #4 10-13-2005, 06:24 AM

ok today i hooked up a signal generator to the temp gauge wire and it seems to work fine, gauge went from hot to cold when i varied the resistance knob from 0-60 ohms.only problem is the damm sending units are all way off from those readings and they are susposed to be for the gauges i have tried 4 of them from resto sources and they are no where near 0-60 ohms, more like 250 ohms hot and 0.591 k ohms cold i have checked the grounds etc??

suggestions anyone

Enoch · #5 10-14-2005, 12:53 AM

I have had this problem with corvettes for a while. The new sending units arent calibrated to work with the old gauges. If you sell a part don't you think that you would make it right

. They sell a kit for you to splice in a do-hickey (that's technical for piece of crap) that makes it work. I will never do this. What I do and you will also is to find an original sender and use it. Hope this helps, Rich.

budnate · #6 10-14-2005, 02:21 AM

how are you ohming the senders??????

I just ohmed out a gm piece ..... from the tip where the wire connects to the threads of the brass housing or the probe/tip I read 800 ohms...the senders for the idiot lights and the gauges are the same right????

**Steve Shauger** · #7 10-14-2005, 02:58 AM

no, idiot light senders work similar to a switch on/off. A gauge temp sending unit changes resistance in proportion to temp changes in a linear manner over a broad range.

Jacsey 70Z · #8 10-14-2005, 03:33 AM

I had a similar problem, and couldn't find a source for the threaded end temp sender. Then I found one here and it worked Great and seems to finally read right. The threaded end unit is 01513462 Good luck.

http://www.lectriclimited.com/mainpage.htm

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