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#1 |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Instrument cluster compatible?
Can anyone tell me if these instrument clusters are compatible with a 1974 GMC pickup?
http://www.ebay.com/itm/73-87-CHEVY-...1c0bba&vxp=mtr |
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#2 |
Account Suspended
Join Date: Jun 2011
Location: Des Moines, IA.
Posts: 4,143
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Re: Instrument cluster compatible?
Compatible? Yes. Plug and play? No.
You need to re-pin, add an oil pressure switch, swap out to an 89 speedo cable. |
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#3 |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
I have a gauge cluster now. Is re-pinning necessary when replacing it with a gauge cluster? On second thought is re-pinning necessary for changing over from ammeter to voltage meter?
Last edited by t5noel; 01-11-2015 at 06:19 PM. |
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#4 |
Account Suspended
Join Date: Jun 2011
Location: Des Moines, IA.
Posts: 4,143
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Re: Instrument cluster compatible?
Yes because the dash harness plug-in is different through the years.
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#5 | ||
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,359
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Re: Instrument cluster compatible?
Quote:
Quote:
Since your 74 is wired for a factory gauge cluster with an ammeter, only a 73 - 75 gauge cluster will be a direct plug-in swap. A 76 or 77 gauge cluster (with a mechanical oil gauge & voltmeter) would be relatively easy to adapt ... you'd only have to change a couple wires to switch from an ammeter to the voltmeter. And in some cases a wire for the brake warning light. More significant changes were made to the cluster plug pin-out when these clusters were changed over to electric oil pressure gauges. |
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#6 | |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
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#7 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,950
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Re: Instrument cluster compatible?
You can do it.
You'll need the factory wiring manuals for the donor and the 1974. Look below... Patience along with a roll of masking tape and a sharpie to mark each wire before you remove it is a good idea. These Cluster connector wiring pinouts are pretty good. BEWARE. There are a couple errors in colors. http://67-72chevytrucks.com/vboard/s...d.php?t=456877
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#8 |
Moderator
![]() Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,950
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Re: Instrument cluster compatible?
One thing I failed to mention is the fact that the later clusters have electric oil pressure senders while your 74 has a Bourdon Tube oil pressure gauge with a copper line running through the firewall to the engine.
If you were moving from warning lamps to gauges you would already have an oil pressure sender wire. You have gauges so you'll have to route an oil pressure sender wire. You can likely utilize the open oil warning switch/lamp Circuit #31 spot in the bulkhead plug with Delphi Packard 56 male and female terminals on SXL wire. That spot should be unused on your gauge cluster truck. If you want to be "correct" about it use Dark Blue wire. The 8900371 instrument cluster plug is obsolete and likely the terminals are as well. A terminal and wire pigtail will need to be salvaged from a 73-87 GM truck.
__________________
1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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#9 | |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
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#10 | |
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,359
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Re: Instrument cluster compatible?
Quote:
I believe the GM #8993106 (1/2" NPT threads) is discontinued but last time I checked the #8993146 (3/8" NPT threads) was still available. I don't know if the aftermarket replacements for these units are close to the original specifications. Or if they have issues similar to the ones that have been discussed in other threads about the replacements for the #1513321 that was used with the 78 & older gauges. |
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#11 |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
I've examined the difference between the two. There will be two additional ground wires and one additional power wire. Can I splice the added ground wires from the one ground? I would assume the added fused power would have to come from the fuse box. There are two wires for the fuel sender. Is the second for dual tanks? Can it be left out if so?
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#12 | ||
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,359
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Re: Instrument cluster compatible?
Quote:
The same goes for the additional ignition-switched fused power wire. That can be spliced into one of the existing circuit #39 power wire(s) already leading to the cluster. Quote:
The fuel sender wire leading to cavity #18 is used for clusters with the large fuel gauge located to the right of the speedometer. I believe it's also used for medium-duty truck tach clusters with the small fuel gauge at the bottom of the tach. The fuel sender wire leading to cavity #7 is only used for tachometer clusters that have the small fuel gauge down in the lower left corner. So depending on the style of cluster you're installing, only one of the 2 wires for the fuel sender will actually be used. I suppose you could remove the extra one but leaving it in there won't hurt anything ... the unused one just dead-ends at the cluster plug since there is no mating trace on the printed circuit. |
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#13 | |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
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#14 | |
Registered User
Join Date: Nov 2009
Location: Sherman, ME
Posts: 2,359
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Re: Instrument cluster compatible?
Quote:
Here's a photo that shows where to insert the removal pick ... my fancy tool is just a piece of old hacksaw blade with the end ground down narrow enough to fit the slot in the connector. ![]() |
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#15 | |
Post Whore
![]() Join Date: Aug 2014
Location: Sacramento, CA
Posts: 10,826
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Re: Instrument cluster compatible?
Quote:
I am in the exact same boat [ahem] truck, also a '74 GMC looking for a Tach / small fuel gauge cluster, I have not seen any at the 4 local junkyards I frequent though, and eBay prices are redunculous, have you seen the guy asking $500 bucks for an OEM Tachometer yet? |
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#16 | |
Registered User
Join Date: Dec 2011
Location: Maryville, TN
Posts: 34
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Re: Instrument cluster compatible?
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#17 |
Registered User
Join Date: Apr 2014
Location: atlanta ga
Posts: 91
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Re: Instrument cluster compatible?
heres the wiring diagram I made when I swapped a 77 cluster to a 82 cluster
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