1991 electric suburban Speedometer into a 77 K10 square ls swap

[jfkelley]

Can anyone show me how to repin a 91 suburban speedometer to work on my 77 Chevrolet . ..I have searched the internet and i been unlucky and always come back to CK5 looking for answers...I did a LS engine swap from a 2003 Silverado 5.3/4l60E/ with an NP241C …I have an INCOMPLETE 91 Suburban Cluster with JUST the speedometer from a 91 Suburban..I wanted to know if I can swap the Water and Volt gauges into the 91 Cluster …?...Oil Gauges has the copper line running to the gauge …Thanks In advance.

 

[dyeager535]

I think you should be able to do what you are asking. The clock position (low left) is completely different however. I'm not looking at one, but I think the back of the speedometer area is what is different for the PCB. I assume that could just be cut out. I "hard wired" my electric speedometer due to that hokey connector they used.

 

[jfkelley]

I think you should be able to do what you are asking. The clock position (low left) is completely different however. I'm not looking at one, but I think the back of the speedometer area is what is different for the PCB. I assume that could just be cut out. I "hard wired" my electric speedometer due to that hokey connector they used.

Can you explain how you hard wired your speedometer…Yeah the connector is very wobbly when inserted

 

[dyeager535]

I probably could have soldered directly to the "fingers" where the connector goes, but I decided to drill holes through each contact, run the wire through, twist it back on itself, then solder it that way. Felt I would be less likely to mess up the trace overheating it that way.

I hardwired the entire cluster, so I completely eliminated the similarly hokey instrument panel connector. Now it's a proper male/female locking setup. But you wouldn't need to go that far. Just depin the proper wire on the existing connector for the fuel sender, cut it off, connect it however you like, and take power and ground from one of the other cluster wires that is appropriate.

 

[jfkelley]

I probably could have soldered directly to the "fingers" where the connector goes, but I decided to drill holes through each contact, run the wire through, twist it back on itself, then solder it that way. Felt I would be less likely to mess up the trace overheating it that way.

I hardwired the entire cluster, so I completely eliminated the similarly hokey instrument panel connector. Now it's a proper male/female locking setup. But you wouldn't need to go that far. Just depin the proper wire on the existing connector for the fuel sender, cut it off, connect it however you like, and take power and ground from one of the other cluster wires that is appropriate.

I think I’m going to go this route …just have to figure out what color wires go to which gauge ..I can find every other print out but can’t find a cluster schematic for 76 K10 online no where

 

[obijuank5]

Do yourself a favor and download or buy the factory service manual for your truck. They were available at 67-72 forums or just the hard copy on eBay or something.

 

[dyeager535]

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But you can also figure everything out by just looking at the flex circuit and gauges too. Three wires for the majority of them, power, ground, and sending unit. Power and ground are generally common, though IIRC, the earlier clusters had a couple of each.

 

[blackhemirt]

I know it's not related to your question so forgive me if it's not relevant. but don't forget you're gonna need to ground pin 16 (green connector) on your pcm when/if using 4wd low range or your trans won't shift. Ask me how i know lol

 

[jfkelley]

The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - PDF of Square Schematics & GM Training Manuals

Community resources for all classic chevy and gmc pickup trucks

67-72chevytrucks.com

But you can also figure everything out by just looking at the flex circuit and gauges too. Three wires for the majority of them, power, ground, and sending unit. Power and ground are generally common, though IIRC, the earlier clusters had a couple of each.

 

[jfkelley]

On the 76 Schematic I’m looking at I see the following and I really had to squint

DK Green - Temp
Tan - Fuel
Oil Mechanical
Cluster lights- Grey
Ignition -Pink
Light Blue - Left indicator
Dark Blue Right indicator
Fuel Sending Unit is it Tan or pink ?76K1076 Schematic

 

[jfkelley]

76k10 Pin

 

[jfkelley]

I know it's not related to your question so forgive me if it's not relevant. but don't forget you're gonna need to ground pin 16 (green connector) on your pcm when/if using 4wd low range or your trans won't shift. Ask me how i know lol

Thanks for reminding me

 

[jfkelley]

I know it's not related to your question so forgive me if it's not relevant. but don't forget you're gonna need to ground pin 16 (green connector) on your pcm when/if using 4wd low range or your trans won't shift. Ask me how i know lol

@blackhemirt can you send me on how to ground pin 16 connector on the pcm ? ..My first LS swap still muddling through it all ..Thanks

 

[blackhemirt]

You're PCM should have two 80 pin connectors, one green one blue. The pins are numbered like the pic below. So first is to locate pin 16 on the geen connector,should be a gray/black wire. If the pin slot is empty for some reason you'll need to find an unused wire with a contact pin on it and move it to pin 16. How you want execute a switch is up to you,a simple on/off toggle switch will work. Run the wire from pin 16 to one terminal on the switch and a ground wire to the other terminal on the switch and your done. I went one step further and mounted a micro switch directly the 4×4 shifter,so this process would happen automatically when in 4 LOW so i don't have to think about it. also if you pick up a momentary switch like the one pictured (instead of on/off) you can use the same process to add a tow/haul mode switch if you want. Just add another pin/wire to #71 on the blue connector, and wire the same only this is a momentary switch to ground that will toggle tow haul on/off. Tow/haul will always defaults to off when you cycle power.