Afraid to ask (idiot light swap)

Cams85GP

Not-quite-so-new-guy
May 30, 2021
25
47
13
Ontario Canada
Feel free to roast me here, but I’ve searched so much to try and find an answer.
I did see a post about someone on here doing the exact thing I want to do, swap auto meter gauges into a Grand Prix, unfortunately he didn’t have pictures showing the wiring behind the dash.

Basically, I want to safely cut out any wires I don’t need, and reuse what I can with mechanical gauges: oil, temp, volt

I’m assuming the colors on the Malibu racing diagrams are the same across G bodies, but for some reason I just can’t wrap my head around what wire goes where.

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ELCAM

Royal Smart Person
Jun 19, 2021
1,124
1,270
113
What exactly are you wanting to do?

What gauges will you reuse? None? The speedometer and clock?

Does your car have cruise control?

Are you really going to use mechanical gauges? Tube feeding the oil pressure and a thermocouple to the temperature gauge? Or electrical sending unit gauges?

This is easy to do just need to know what you are really trying to accomplish.

There has to be another wiring connector, there are not enough wires in that one to run everything.
 
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Cams85GP

Not-quite-so-new-guy
May 30, 2021
25
47
13
Ontario Canada
No cruise control, keeping the Speedo and clock, and just swapping out the factory idiot lights for proper gauges.
That connector was all that connected to the back of the original cluster into that plastic sheet fuel, oil,temp, volts.


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Built6spdMCSS

Geezer
Jun 15, 2012
5,804
9,715
113
Florida Beach
Get a multimeter and basically back probe the printed circuit from the light to where it is on the connector. Do that for all of them if need be. I've done it, it's pretty easy once you get the hang of it. Sometimes the circuit is labeled.
 

ELCAM

Royal Smart Person
Jun 19, 2021
1,124
1,270
113
Likely need the red splices, the wires are small gauge.

Use a quick splice to tap into the dash illumination, will go to the orange/red wires on your new gauges.
Black wires go to ground whether you quick splice off that connector or get it elsewhere.

Quick splice off the purple with black stripe wire +12V to the + side of the volt gauge, connect the ground you used for the dash illumination circuit for the ground terminal on the volt gauge.

Done

No cutting required.

splice.jpg

dash wiring.png
 

pagrunt

Geezer
Sep 14, 2014
9,168
15,349
113
Elderton, Pa
Make things simple with plug 2 which goes with the gauge or warning light cluster by plug cavity number:
1. Tan, oil pressure gauge or light, 31
2. Black, ground, 150
3. Blank
4. Pink/black stripe, key hot power, 39
5. Pink, fuel gauge, 30
6. Gray, dash lighting, 8
7. Pink/black stripe, key hot power, 39
8. Dark green, temp gauge or light, 35
9. Black, ground, 150
10. Brown, gen/volt warning light, 25
I have a few of these clusters so I was able to list the wires. As for plug one I don't have a speedo cluster to trace.
One tip I have is don't use the blue (or any color) Scotch-locks for a splice, best to use butt connectors. I prefere to use bare ones & shrink tube them after they are spliced. I aslo do my work to look like a factory set up with OE teminals & connectors.
 
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78Delta88

Royal Smart Person
Supporting Member
May 23, 2022
1,307
1
1,095
113
SW Arizona
On the oil use the copper line with metal compression ferrel. Don't use the nylon they can break and you get pressurized oil in the dash.
 
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78Delta88

Royal Smart Person
Supporting Member
May 23, 2022
1,307
1
1,095
113
SW Arizona
Make things simple with plug 2 which goes with the gauge or warning light cluster by plug cavity number:
1. Tan, oil pressure gauge or light, 31
2. Black, ground, 150
3. Blank
4. Pink/black stripe, key hot power, 39
5. Pink, fuel gauge, 30
6. Gray, dash lighting, 8
7. Pink/black stripe, key hot power, 39
8. Dark green, temp gauge or light, 35
9. Black, ground, 150
10. Brown, gen/volt warning light, 25
I have a few of these clusters so I was able to list the wires. As for plug one I don't have a speedo cluster to trace.
One tip I have is don't use the blue (or any color) Scotch-locks for a splice, best to use butt connectors. I prefere to use bare ones & shrink tube them after they are spliced. I aslo do my work to look like a factory set up with OE teminals & connectors.
This is a real good list. Thanks for posting.
 
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