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Temp Sending Unit Connector Help

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Old Apr 7, 2026 | 04:20 PM
  #1  
surfer_brooo's Avatar
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Car: 1986 Trans Am
Engine: Carbed 305
Transmission: 700R4
Temp Sending Unit Connector Help

I have a nail head style temp sending unit, but I can't remember what connector came off of it. I'm kind of assuming it hooks up to the double connector, but I'm not sure if it goes on the one on the right or the left. There are also a couple of other connectors in this strand of wiring that I don't have a clue what they are for.

For reference, I'm doing a 350 swap with no A/C and no ECM. Any help is appreciated!






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Old Apr 7, 2026 | 04:33 PM
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Re: Temp Sending Unit Connector Help

The 2-pin one is for the AC compressor.

The melted one looks like it might have gone to the temp gauge sending unit in your hand. If the wire is dark green - kinda hard to tell exactly in the photo - then it may have. I doubt it though, the body of that connector was almost always "white", and didn't have the little latching feature. The one in your hand is more likely to be the throttle kicker solenoid which also is a dk grn wire.
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Old Apr 7, 2026 | 04:48 PM
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Car: 1986 Trans Am
Engine: Carbed 305
Transmission: 700R4
Re: Temp Sending Unit Connector Help

I think I just answered my own question

Found this connector just sitting in the engine bay and a matching wire that either got cut or melted off. I guess I'll just trim it and order a new connector and splice.



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Old Yesterday | 07:03 AM
  #4  
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From: Central North Carolina
Car: 1992 Teal RS
Engine: 350 Carbed
Transmission: 700R4
Axle/Gears: 4th Gen Rear 3.42
Re: Temp Sending Unit Connector Help

1st pic what's in your hand is either knock sensor or fan switch. Knock sensor goes in pass side block, but if your doing carbed 350 swap you won't need it. Fan switch goes in pass side head between #4. & #6 spark plugs. Personally I'd plug fan switch hole in head and get a separate adjustable fan controller that probes radiator. I have a Flex-a-lite controller it's literally been the best money I've spent on auto part - 18yrs since install & ALWAYS works.

Coolant temp sensor on driver side head between #1 & #3 spark plug, has one wire to it. Some cars have temp sensor in thermostat housing.
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Old Yesterday | 08:22 AM
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Re: Temp Sending Unit Connector Help

1st pic what's in your hand is either knock sensor or fan switch.
No. It's similar to those, butt is not that.

It's part of the compressor harness. Goes to the high-pressure limit switch in the back of the compressor.

Coolant temp sensor on driver side head between #1 & #3 spark plug
There's no [mr_spock] sen-sore [/mr_spock] in that location. Only the temp gauge sending unit, which is the object in the photo with the "mushroom" or "nail head" connector. The coolant temp sensor on a carb V8 is in the water outlet (the thing the top rad hose hooks to) and has 2 wires, a yellow and a black.

Since you found the temp gauge wire, the other green wire with the single melted connector, is probably for the "kicker" solenoid on the side of the carb.

There's nothing wrong with the fan switch in the head. It's probably better there in fact than one stuck through the rad, although those do work well enough. Butt a non-HO carb car doesn't have an electric fan anyway so it's a moot point in this case.
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