Cluster Interchange Question

[jjewett444]

I hate to start a new topic about this because it has probably been asked a million times. I have google searched and searched this sites search bar even 73-87.com and still I cannot find a direct question so here I go....

Will a complete non tachometer cluster from a 1979 k10 directly plug and play into a 1984 c10? the 1979 has a 100mph speedometer and my 1984 has 85 mph speedometer. both have voltmeter and electric oil pressure gauge. I paid $26 at local pick n pull for the complete cluster. so not a huge loss but would like to have all of my gauges working properly and this appears to be in better shape than mine.

Also another but unrelated question. found a 1970 steering wheel and I thinks the splines line up to my column but the locking plate is in the way from it sully seating, would I be fine removing my locking plate as far as not disturbing anything in my column? horn contact or anything else?

well thanks fellas in advance,

-Jim

 

[gmachinz]

Offhand your stock 1984 cruise control isnt compatible. There are some re-pinning requires but I am not sure what is involved-Ive swapped plenty of clusters but not 73-80 for 81-up or vice versa.

 

[jjewett444]

thanks, I actually eliminated my cruise control a while back so that is not an issue. most important to me is fuel, speedo and temp, but would prefer to have all Lol

 

[Green79Scottsdale]

Found this.... "81-84: ‘78 and up tachometer cluster will work as a “plug in and go”, but you will not have use of your factory cruise control if the truck is an ’83 or newer (the green box behind the speedometer)."

Yes it should work, but as gmachinz stated, some minor re-pinning may, or may not, be required. Get the electrical schematics for a '79 and an '84 and compare them. Re-pinning the plug for the cluster is actually super simple, you just need to get the wires to the right position.

Everybody told me I was going to have to re-pin the plug on my '79 when I swapped in my tach cluster, but none was needed. That's why I say compare the schematics, maybe nothing needs to be done.

 

[gmachinz]

I agree with the above. I want to say you get into a couple hiccups when you go putting a 78-up tach cluster into a 73-77 truck.

 

[jjewett444]

ok got it in and plugged in and everything seems to work except for the speedometer. might just be bad or because its a 100 instead of 85 idk. I tried pushing in the cable further and the needle bumped to 35mph and stays there

 

[bucket]

I agree with the above. I want to say you get into a couple hiccups when you go putting a 78-up tach cluster into a 73-77 truck.

Yeah, besides the VSS box, the '78-'89 stuff all swaps around.

ok got it in and plugged in and everything seems to work except for the speedometer. might just be bad or because its a 100 instead of 85 idk. I tried pushing in the cable further and the needle bumped to 35mph and stays there

Something with the speedo is amiss, they are calibrated the same.

 

[jjewett444]

just swapped my old speedo with the 79 cluster, gonna see today if all is well. found out that the white plastic backing part of the cluster from the 79 truck has a housing about half of the circumference of where the speedo gauge pokes through the back to allow the cable to attach and has its own locking device for the cable, while my 84 cluster is flush on the back where the speedo comes through and the speedo itself has the cable lock. it doesn't seem the make a huge difference being that the cable seems to go into it far enough thought I would point that out.

I stuck a wd-40 can straw in the back where cable attaches to the 1979 speedo and when I try and turn it, it scrapes on metal. there is play and when I move it toward the back the thing moves. seems to be junk to me

thanks fellas for all of the help, will update on the speedo later

 

[42Grand]

Yeah, besides the VSS box, the '78-'89 stuff all swaps around.



Something with the speedo is amiss, they are calibrated the same.

I know this is an old thread but I’ve been digging and haven’t found the exact answers I’m needing. I have a 77 with a standard cluster but purchased a used 78 cluster with a tach. Oil sending unit is different and the board is as well. If I swap the board, gauges and lighting, what else do I need to do with the oil sending unit? Will that swap over easily as well? I would love a DIY if anyone knows where to point me. Thanks in advance!

 

[AuroraGirl]

I know this is an old thread but I’ve been digging and haven’t found the exact answers I’m needing. I have a 77 with a standard cluster but purchased a used 78 cluster with a tach. Oil sending unit is different and the board is as well. If I swap the board, gauges and lighting, what else do I need to do with the oil sending unit? Will that swap over easily as well? I would love a DIY if anyone knows where to point me. Thanks in advance!

assuming you have 4 gauges On the left? not dummy lights? the oil pressure sender should be behind distributor, the only time you need to do extra is if you have the bypass for electric choke on the same port, then you just need an adapter. the non-gauge cluster uses a different sender than a gauge cluster.
You should be able to swap cluster or boards.. but you are gonna have to do repinning and depending on when anmeter was phased out etc you may have work there.
also, i think 79 or 80 saw a different type face than 78 and older.

basically, if your 78 cluster is nice, find a wiring diagram for a 78 and go off that @Catbox has the fsm for the year.
But your sending unit for coolant will also need to change. different resistance values and maybe connector.
check anmeter/voltmeter
I think fuel gauge is ok
youll need a wire to the tach signal on distributor
speedo cable should work me thinks????

above all check those wiring schmatics. id almost say just go get a new board that matches your trucks pin out and do it as a conversion of tach not year range + tach, but then i think you would need to change a few gauges... maybe. maybe different senders.

 

[42Grand]

assuming you have 4 gauges On the left? not dummy lights? the oil pressure sender should be behind distributor, the only time you need to do extra is if you have the bypass for electric choke on the same port, then you just need an adapter. the non-gauge cluster uses a different sender than a gauge cluster.
You should be able to swap cluster or boards.. but you are gonna have to do repinning and depending on when anmeter was phased out etc you may have work there.
also, i think 79 or 80 saw a different type face than 78 and older.

basically, if your 78 cluster is nice, find a wiring diagram for a 78 and go off that @Catbox has the fsm for the year.
But your sending unit for coolant will also need to change. different resistance values and maybe connector.
check anmeter/voltmeter
I think fuel gauge is ok
youll need a wire to the tach signal on distributor
speedo cable should work me thinks????

above all check those wiring schmatics. id almost say just go get a new board that matches your trucks pin out and do it as a conversion of tach not year range + tach, but then i think you would need to change a few gauges... maybe. maybe different senders.

I’ll refer to your post while doing more research. The existing cluster has the brake light in the lower left corner, big fuel gauge on right and oil line for oil pressure. New cluster has fuel in lower left, large tach on right and electrical oil sending unit. I cleaned up both assemblies last night and pieced the best parts into the new tach cluster. The wiring in the back is different for sure but I haven’t started tracking the wiring to see if re-pinning is necessary, I assume it will be though. Here are pics of the backs of both devices. Blue is the old no tach while copper color is the new with tach

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[Green79Scottsdale]

With your 77 having a mechanical oil pressure gauge, you will of course need to track down where that comes from the engine and do the appropriate work to put in an electrical pressure gauge. I have never done it, so I can't help you there.

As said above, comparing wiring diagrams is essential. I am going to predict that you will need to re-pin. Both clusters have voltmeters, correct?

Shouldn't be to hard of a swap. Might just be a bit of leg work to get it done.

 

[42Grand]

With your 77 having a mechanical oil pressure gauge, you will of course need to track down where that comes from the engine and do the appropriate work to put in an electrical pressure gauge. I have never done it, so I can't help you there.

As said above, comparing wiring diagrams is essential. I am going to predict that you will need to re-pin. Both clusters have voltmeters, correct?

Shouldn't be to hard of a swap. Might just be a bit of leg work to get it done.

Yes, both have voltmeters. I will for sure have to re-pin. Here are some comparison pics of the wiring that I did just to make sure the wires will be pinned correctly.

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Couple more questions though...

How do I go about checking the gauges to make sure they are the same?

My original speedo went to 100 but the new one goes to 85. Why is that? I’m using my 100 because it still has the needle.

Does anyone have a wiring diagram for my gauge wiring clip? If so, it would cut down on time doing research to find it.

 

[Green79Scottsdale]

Not sure about checking the gauges.

100 vs 85 mph speedos changed with the gauge fonts, IIRC. I'm thinking like 1980?

Wiring Diagrams... https://www.gmsquarebody.com/threads/1973-1991-wiring-manuals.14498/

Also, this link may or may not be helpful.... https://www.73-87.com/7387garage/interior/factory tachometers.htm

 

[42Grand]

Wow! Tons of good info. Thanks a lot! I need to check the tach and make sure it works before I change my harness and go all in. That would be horrible if it didn’t work after all this work. [emoji37]