Factory tach wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

fade94 · 08-18-2005, 10:34 AM

What hooks where?

byrd · 08-18-2005, 11:49 AM

The terminal on the right if looking up at the tach from under the dash is positive which goes to unfused ingnition hot on the truck fuse box( you should use a inline fuse for this fused @ 3 amps) and the other terminal is the signal from your dizzy( neg on points coil, or hei has a spot marked tach) Hope this helps....Randy

fade94 · 08-18-2005, 12:02 PM

Too make sure, please let me know what goes on A and B...
Thanks again.

**GSFMECH** · 08-18-2005, 04:54 PM

When you get it check it on the back. The connections are marked, one is marked 12 V and will plug in under the dash on your fuse box on the unfused hot terminal when the ign. switch is ON. the other goes to the coil as Byrd said I think it is marked "com" or something like that. If you buy one of the repop harnesses (they are cheap) it will plug in. There is a dimple on the firewall near the fusebox where you can drill the hole for the wire to pass to the engine compartment if you want it factory. The assembly manual shows where it is and I can take a pic if you need it.
Mike

byrd · 08-18-2005, 08:51 PM

I thought there was a plastic knockout above where the speedo comes out of the cab, and that is where the tach wiring enetrates the firewall. Is that not correct? Randy

**pjmoreland** · 08-18-2005, 11:19 PM

There's a cardboard knockout in the firewall insulation, but you have to drill a 3/4" hole in the sheetmetal of the firewall.

fade94 · 08-19-2005, 09:26 AM

WOO HOO....It works....
Now, if I could just refurbish the face of the tach and speedo. My other gauges are really nice. I saw a post about this, but the link provided was for a complete set of overlays. I just need the speedo and tach. ANY ideas on just doing one or two gauges? I did not subscribe to the thread about restoring gauges and can't find it now.

08-18-2005, 10:34 AM	#1
fade94 Registered User Join Date: Mar 2005 Location: Melissa, TX Posts: 799	Factory tach wiring What hooks where? __________________ 68 short bed driver (71 clip on it now, swapping to 68 when weather cooperates) 67 short step project (will get SWB from the 68) 67 Camaro, #'s matching (my wife's) 03 Dodge Ram 2500 4x4 diesel 5 speed 4.10 rear

08-18-2005, 12:02 PM	#3
fade94 Registered User Join Date: Mar 2005 Location: Melissa, TX Posts: 799	Too make sure, please let me know what goes on A and B... Thanks again. Attached Images __________________ 68 short bed driver (71 clip on it now, swapping to 68 when weather cooperates) 67 short step project (will get SWB from the 68) 67 Camaro, #'s matching (my wife's) 03 Dodge Ram 2500 4x4 diesel 5 speed 4.10 rear

08-18-2005, 04:54 PM	#4
GSFMECH On the road Join Date: Jan 2004 Location: NATCHITOCHES LOUISIANA Posts: 815	When you get it check it on the back. The connections are marked, one is marked 12 V and will plug in under the dash on your fuse box on the unfused hot terminal when the ign. switch is ON. the other goes to the coil as Byrd said I think it is marked "com" or something like that. If you buy one of the repop harnesses (they are cheap) it will plug in. There is a dimple on the firewall near the fusebox where you can drill the hole for the wire to pass to the engine compartment if you want it factory. The assembly manual shows where it is and I can take a pic if you need it. Mike __________________ Mike Castro- 72 SWB. Ochre and White. 496/400 turbo, GV OD ,Dakota Digital dash , tilt, Vintage Air, PS, hydro boost, factory buckets, console, QA-1 Coil over suspension, 20/20"Billet Specialties Magnetos 72 SWB. Med blue. 454/400 turbo, tach, tilt, Stock AC, PS,PDB, factory buckets, console, ECE 4/6 drop w/ 2" blocks and C-notch, 20/20"Coys- Crashed and destroyed by drunk driver Sept 2019. New 72 build in the works. My new build thread "Castro" https://67-72chevytrucks.com/vboard/...d.php?t=820934 My old build thread, the blue truck http://67-72chevytrucks.com/vboard/s...d.php?t=271489 www.louisianaclassictruckclub.com

08-19-2005, 09:26 AM	#7
fade94 Registered User Join Date: Mar 2005 Location: Melissa, TX Posts: 799	WOO HOO....It works.... Now, if I could just refurbish the face of the tach and speedo. My other gauges are really nice. I saw a post about this, but the link provided was for a complete set of overlays. I just need the speedo and tach. ANY ideas on just doing one or two gauges? I did not subscribe to the thread about restoring gauges and can't find it now. __________________ 68 short bed driver (71 clip on it now, swapping to 68 when weather cooperates) 67 short step project (will get SWB from the 68) 67 Camaro, #'s matching (my wife's) 03 Dodge Ram 2500 4x4 diesel 5 speed 4.10 rear

08-18-2005, 11:19 PM	#6
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,413	There's a cardboard knockout in the firewall insulation, but you have to drill a 3/4" hole in the sheetmetal of the firewall.



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