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Old 03-28-24, 04:02 PM
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Paulieboy72
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Temp sensor

Could I run a wire from the temp sensor straight to the gauge? As I cannot find the correct wire in the emmisions harness for the temp sensor, if it is there someone hacked it up and changed the colors of the wiring
Old 03-29-24, 12:19 PM
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You could, although you'll just be adding to the hackery that way.

Did the PO hack up the body side of the harness or just the engine side? The wire should be there. If everything is really butchered throw one lead of a multimeter on the gauge cluster pin for the temp gauge, and then start poking around the remains of the harness in the engine bay. Checking for continuity you should find it if it's still there.
Old 03-29-24, 02:30 PM
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I think the temp sensor is on the emmisions harness. The colors don't match the FSM
Old 03-29-24, 02:54 PM
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The NO 1 Water Temp sensor on is on back of the water pump and runs the automatic choke. it's in the harness that goes to to passenger side. You'll want to utilize that same circuit even if you run a new wire, run it to the same connector that goes to the passenger firewall. If you disable the automatic choke, the dash gauge probably won't work currently. Did you at least leave the inside choke **** untouched?
Old 03-29-24, 03:03 PM
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Have not touched the choke however all emmosions have been removed by PO
Old 03-29-24, 04:50 PM
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Be very careful with that water temp sensor. It's really easy to break off the wires where they are encased in that red epoxy. They can be fixed, but still break after being fixed. Just don't twist them. That seems to be when they break.
Old 03-29-24, 08:44 PM
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How about hot glue? Secure them?
Old 03-29-24, 10:06 PM
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Originally Posted by Paulieboy72
How about hot glue? Secure them?
That will work. I've had to solder them back on and it requires skinning them back by removing that epoxy. Hot clue would work after that for keeping them stable.
Old 03-29-24, 10:20 PM
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Ok, there is another temp sensor just to the front of the oil cooler going into rear iron? That's the one I can't find the wire for also
Old 03-30-24, 09:56 AM
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Originally Posted by Paulieboy72
Ok, there is another temp sensor just to the front of the oil cooler going into rear iron? That's the one I can't find the wire for also
That is part of the engine harness. What you have been calling the rat's nest harness. I really don't like calling it the rat's nest harness because it does a lot more then control emissions.

It has the oil pressure, water temp - for gauge, oil level (on pan), and low oil (on pan).

The water temp sensor on the back of thew water pump is also part of that harness but only controls the choke.

Sounds like you might need an engine harness or make your own and plug into the big connector on the passenger's side.
Old 03-30-24, 10:14 AM
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  • Ok
Old 03-31-24, 03:03 PM
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For what it's worth the water temp sensor on the back of the pump housing (for the auto choke) has nothing to do with the gauge. Perhaps that was just misspoken but I wanted to clarify. The two are completely independent.

Is the large emissions harness connector (located near the steering box) still intact, or did the PO cut up the chassis side of it too? You should be able to trace the wire pretty easily if it's intact. If not, do like I said and use a multimeter to check between the gauge cluster pin (can be found in the FSM) and whatever wires remain on that harness. Should find continuity between one of them if it's still there.

Worst case you could find the wire on the gauge cluster connector for the temp gauge, cut it, and run a new wire from there. I wouldn't suggest that until you've exhausted your other options however.
Old 03-31-24, 03:07 PM
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I have the complete emmisions harness, got the #1 sensor on back of water pump. The #2 one is just below the oil cooler. This one I can't figure out. FSM says the connecting wire is on the front harness bit looks like there is a wire on the emmisions harness that fits on the sensor, however the wire colors are not correct
Old 03-31-24, 03:10 PM
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All o need is coolant temp. I don't need coolant level, oil level and such just oil pressure and coolant temp. Also I have to hookup the neutral switch.
Old 03-31-24, 03:31 PM
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Could you take a photo of the harness so we can see what you're dealing with? If I recall correctly the wire (at least on my car, a 1980) is yellow with a green stripe, although I could be mistaken.

The wire for the temp gauge should be on the emissions harness, not the front harness. There is occasionally an additional temp sensor on the radiator itself, although I don't recall its function, perhaps that's what you're finding in the FSM?
Old 03-31-24, 04:24 PM
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Originally Posted by KansasCityREPU
The NO 1 Water Temp sensor on is on back of the water pump and runs the automatic choke. it's in the harness that goes to passenger side. You'll want to utilize that same circuit even if you run a new wire, run it to the same connector that goes to the passenger firewall. If you disable the automatic choke, the dash gauge probably won't work currently. Did you at least leave the inside choke **** untouched?
I want to correct myself. The sensor on the back of the water pump housing does not control the gauge. I confused myself because I ran and extra sensor to the back for an additional gauge. I used an S4 aluminum water pump housing on my1985 12A.

Last edited by KansasCityREPU; 03-31-24 at 04:32 PM.
Old 03-31-24, 04:30 PM
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Originally Posted by Benjamin4456
Could you take a photo of the harness so we can see what you're dealing with? If I recall correctly the wire (at least on my car, a 1980) is yellow with a green stripe, although I could be mistaken.

The wire for the temp gauge should be on the emissions harness, not the front harness. There is occasionally an additional temp sensor on the radiator itself, although I don't recall its function, perhaps that's what you're finding in the FSM?
For at least 1984/1985, there is a third water temp sensor on the driver's side midway down on the radiator. Not sure what it does.

The water temp gauge sensor wire is connector C15 Yellow-White page 50:18 of the 1985 wiring diagram.
Old 03-31-24, 07:15 PM
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Ill take pics when I get home from down south
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