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Old 01-08-2023, 10:19 AM   #1
72malibu
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Ammeter to Voltmeter Conversion '75

Hello!

I've been searching threads but most are focused on the 72 and earlier gauge conversions.

Is this the best way to do the conversion for a 75? There are no photos of the backside of the cluster. Do you leave the printed circuit in place?

http://www.73-87chevytrucks.com/tech...geSwapR1-0.pdf
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Old 01-08-2023, 07:54 PM   #2
ray_mcavoy
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Re: Ammeter to Voltmeter Conversion '75

Yes, that looks like a good method.

No, there would be no need to make any changes to the printed circuit on the back of the cluster. As described in that article, simply removing the two 4 amp fuses (located in the little rubber holders under the hood) will electrically isolate the old ammeter traces on the printed circuit.

About the only thing I might do differently would be to use a small plastic or fiber insulating washer (instead of a piece of electrical tape) to insulate between the case and ring terminal on the temp gauge power stud.
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Old 01-09-2023, 12:09 PM   #3
SCOTI
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Re: Ammeter to Voltmeter Conversion '75

Quote:
Originally Posted by 72malibu View Post
Hello!

I've been searching threads but most are focused on the 72 and earlier gauge conversions.

Is this the best way to do the conversion for a 75? There are no photos of the backside of the cluster. Do you leave the printed circuit in place?

http://www.73-87chevytrucks.com/tech...geSwapR1-0.pdf
I did this swap on my 74. Removed the ammeter gauge & swapped the voltmeter in place. Grounded the voltmeter to a spot on the cab wall & utilized an existing 12v wire already under-the dash as the power source. Printed circuit left untouched. This was 20yrs ago, but I recall there was a tab between the circuit board & plastic housing that the ammeter gauge studs contacted. I popped it out & the voltmeter studs were shorter so there was no issue w/the printed circuit being left as-is.
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Old 01-15-2023, 04:33 PM   #4
72malibu
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Re: Ammeter to Voltmeter Conversion '75

Thanks for all the info.

I did this today. I ran power and ground wires from the volt gauge to the temp gauge. I removed the two connectors/clips from the housing/printed circuit board, just in case somebody puts the fuses back in the harness, so it's "idiot proof."

I took the ceramic insulator off the old amp gauge, broke it into 3 pieces, and used the two outer pieces with holes for the studs as insulators on the volt and amp gauges (instead of electrical tape). Clock them at an angle to the existing insulator and they fit fine.

For this '75, I used volt gauge LMC 36-1846. It matches the font of the existing gauges the best.

I also replaced the broken gear indicator using LMC 32-7236. But because the font on the new bezels don't match the '75, I ended up taking the spring, sliding pointer, and pull wire assembly off the new bezel and attaching it to the old bezel.
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Old 02-22-2023, 05:02 PM   #5
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Re: Ammeter to Voltmeter Conversion '75

moved forums

Last edited by kglowacky; 02-22-2023 at 05:58 PM. Reason: wrong forum
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