Coolant temp gauge

Winkernod

Greasemonkey
Sep 13, 2018
139
63
London Ontario
When I did the LS swap in my 80 Grand Prix with a 301 I tagged the wires and everything went good except I have never had the temp gauge working all others worked. So that has been one of the things I have been trying to sort out. I have the Camaro 3 wire sensor and it is reading properly in the ECM. I have grounded the wire I had hooked up and the gauge stays at 0. The wiring diagram I have shows the temp wire should be a dark green I have also found a wiring diagram saying green with a white stripe. I have tried grounding several different green wires.
here is a picture of the wire I had hooked up I wonder if anyone could identify it

1584886363403.png

1584886389795.png

1584886421783.png
 

pagrunt

Geezer
Sep 14, 2014
6,208
113
Elderton, Pa
Maybe using an extra port put in a single blade sender that has the same resistance to the 301's unit to make the gauge work. Might even be able to use the 301's or a 3/8" thread unit with a metric adapter. This way you can leave the LS's for the computer to use. Keep in mind I'm not a LS guy but just thought of what could be a simple fix to the gauge issue to keep the original working.
 

Winkernod

Greasemonkey
Thread starter
Sep 13, 2018
139
63
London Ontario
Maybe using an extra port put in a single blade sender that has the same resistance to the 301's unit to make the gauge work. Might even be able to use the 301's or a 3/8" thread unit with a metric adapter. This way you can leave the LS's for the computer to use. Keep in mind I'm not a LS guy but just thought of what could be a simple fix to the gauge issue to keep the original working.
That might be a good idea and I might just do that after I determine for sure what wire is actually going to the gauge. I cannot seem to determine that for sure. Am I correct to assume if I ground the correct wire the coolant gauge would pin on the hot side.
 

pagrunt

Geezer
Sep 14, 2014
6,208
113
Elderton, Pa
That might be a good idea and I might just do that after I determine for sure what wire is actually going to the gauge. I cannot seem to determine that for sure. Am I correct to assume if I ground the correct wire the coolant gauge would pin on the hot side.
The wire for the temp sender is a green 16 gauge wire. It'll be the only green wire in the engine harness. I'd try an ohm meter to excite the gauge thru the wire to aenure the gauge is functioning.
 

Winkernod

Greasemonkey
Thread starter
Sep 13, 2018
139
63
London Ontario
The wire for the temp sender is a green 16 gauge wire. It'll be the only green wire in the engine harness. I'd try an ohm meter to excite the gauge thru the wire to aenure the gauge is functioning.

Just trying to remember this is the engine harness correct?

1584904505241.png


I did try grounding that green wire it didn't move. I do believe the gauge is working internally when I crank the engine it goes to full hot. I will try that wire again
 

pagrunt

Geezer
Sep 14, 2014
6,208
113
Elderton, Pa
Just trying to remember this is the engine harness correct?

View attachment 139910

I did try grounding that green wire it didn't move. I do believe the gauge is working internally when I crank the engine it goes to full hot. I will try that wire again
Work from the firewall out with the bulk head harness (the body harness the closest to the fender) & you'll find the green wire there. Just follow or fish it out.
 

Winkernod

Greasemonkey
Thread starter
Sep 13, 2018
139
63
London Ontario
Work from the firewall out with the bulk head harness (the body harness the closest to the fender) & you'll find the green wire there. Just follow or fish it out.
The closest to the fender is the one under the steering column Okay I will look at that. Thanks pagrunt for your help I'm done for today been playing with the car since 8 am it is beer oclock now
 
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