gauge question

[typ901]

just for fun I thought I'd check this before installing.
I get a minor resistance on the TEMP gauge... about 150 ohms. the PRESS side appears open. this gauge is from a '71. is this normal ?
I have a similar gauge from '75 that behaves in the same way and another from '79 that gives a resistance on both gauges.
input appreciated

[typ901]

received this response over on the bird;
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Use your meter, set to ohms, and measure G to ground and G to 12V. You should have a resistance on both. However, the easiest way to test these gauges is to connect 12V and ground then use a little jumper wire connected to ground and touch it to the G terminal. When G is grounded the meter should be pegged all the way up.
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[patjolson]

Ok on my 72 T my pressure gauge STAYS pegged every so often it will give me an accurate read. So I know it can work properly. I have changed the sending unit on top of the engine. No change. Any ideas?

[Arne]

Wiring, Pat. Somewhere in the circuit from the sender to the gauge the wiring is shorting to ground. Frayed insulation, most likely. If you can't find the bad spot you may need to pull a new wire.

[patjolson]

that's a great suggestion I really didn't know where to begin once the sending unit was replaced
thanks Arne.

[Arne]

The wire you need to trace/fix/replace is green w/red tracer. It is a single wire that connects the sender to the back of the gauge, and no where else. If you test it at either end I think you'll find it is currently shorted to ground. That's what causes the gauge to peg at max.

[Scott A]

Pat,
I agree with Arne. Start with the simple stuff.

I tried the simple stuff. And had no fix. So I kept going.
My response is complicated. It was things I didn't expect.
I had the same thing. My fixed may not be yours.
I'll try to simplify what I had to do.

In my 14 pin connector at engine. Someone mixed up the pins.
I found a chart, and checked each one by color.

Also.
On a bench. I opened my sender unit. Which was fun. Saw how it worked. And re-soldered a tiny wire.

[Arne]

I'd run a temporary test wire from the sender to the back of the gauge as a first step before going to the effort of opening up the gauge. Start with the simple stuff first.

[patjolson]

I like that .
I am in the middle of four or five or seven different paths as we speak.
several more to complete before I get to the pressure issue.
whence (i invented that word) I get there I will post you all.