Temp gauge connection from drivers side head

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86c20RN

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1986 C20 454. Recently bought this truck and one issue is the temp gauge not working. From the drivers side the wiring does not connect to anything. I can’t. Find where the connector should attach too in the engine area.








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75gmck25

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Sensor on an SBC is usually in the drivers side head, just below where the exhaust manifold bolts on. If you look straight down between the front exhaust manifold bolt and the two bolts in the center you should see the sensor screwed in. Maybe a 454 is different.

I don’t think that’s the temp gauge wire in your picture, unless GM changed the colors. It should be a single wire and it should be green. It has a black insulating shield around the last 8-10 inches because of how close it runs to the exhaust manifold.
 

AuroraGirl

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I dont know where the wire goes directly from beyond the back ofthe engine like what pass through etc etc but Mine in this photo is pinched in the valve cover LOL it still works even. and seals.
 

bucket

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It can be seen here on my old '86 454.

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It's the green wire going across the valve cover.
 

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I can confirm it still is in the same place and uses the same green wire(but with a waterproof deutsh plug connection) on a 97 Gen VI 454. I have never seen a SBC/BBC in a truck that didn't get the coolant temp gauge signal from the sensor installed in the drivers side head.
 

86c20RN

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Thanks to everyone. I went
Back and looked at mine and the green wire is actually not going into that connector it just looked like it was. Now That I know it’s not disconnected I just need to Troubleshoot. Bucket I am attaching an image of something at the back drivers side top of engine. Any idea what this should be plugged in to or what it is?
 

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Raider L

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@86c20RN,

By the looks of the bottom of that it has a copper appearance to it. That looks like some kind of temp sensor because that copper end with the indentations on it look familiar but I can't place it.

I have my Autometer temp sensor in that place in the drivers side head. I wanted to put it up on the intake manifold but the water neck is in the way. So I used the common place for it.
 

chevyfs

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I dont know where the wire goes directly from beyond the back ofthe engine like what pass through etc etc but Mine in this photo is pinched in the valve cover LOL it still works even. and seals.
Kinda out of nowhere but i love how im not the only one too lazy to unbolt the valve covers for the second time just to take out a lil wire lmaoo
 

AuroraGirl

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Kinda out of nowhere but i love how im not the only one too lazy to unbolt the valve covers for the second time just to take out a lil wire lmaoo
ikr. I mean, in my case, I had snagged it quite a while ago. I havent had the valve cover bolt loose in ages.
when it came time to crimp on a new end for the coolant sender wire, i noticed it wouldnt move at all and it felt short lol!Worked anyway, so I figured not that consequential
 

AuroraGirl

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It can be seen here on my old '86 454.

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It's the green wire going across the valve cover.
3 groove PS? Must have a lot of offset which is why it has a remote reservoir so it can sit closer to the pump itself
 

bucket

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3 groove PS? Must have a lot of offset which is why it has a remote reservoir so it can sit closer to the pump itself

Well dang, I forgot all about that 3-groove pulley. The 3rd 'extra' groove was simply added to the normal spacing at the front. It's only job was to run the secondary smog pump. The other smog pump ran off of the alternator belt.
 

AuroraGirl

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Well dang, I forgot all about that 3-groove pulley. The 3rd 'extra' groove was simply added to the normal spacing at the front. It's only job was to run the secondary smog pump. The other smog pump ran off of the alternator belt.
2 smog pumps RIP
 

bucket

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2 smog pumps RIP

Yeah, I removed them both lol.

Although I did save all that garbage, in case someone wanted it. Which someone actually did. It all went to a nice fella in Colorado last year.
 

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