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Stock Gauges on LS Swap ..Opinions Wanted

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jfkelley

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I’m finishing up my 1976 K10 4x4 5.3/4L60e swap ..I purchased an 1990 Suburban Electric Speedo Instrument Cluster Assembly but the printed circuit on the back is trashed & no one offers a repo where the accessory plug goes into a lot of the fingers are missing ..Really wanted to make the factory gauges work ..Should I hard wire the gauges ? Or Go with Dakota , Intellatronix , Auto meter or Onegauge ? Thanks for your input and time ..This forum has helped me in many ways getting through this swap
 
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I ran my ls swap and now my 8.1 with stock gauges. Mine is a ‘91 so I was already set on the electric speedometer. But the oil pressure and water temp is pretty simple.

Oil pressure is easy. I used a stock squarebody sender and screwed it into the ls oil pressure port. Just need to double check the size of threads match. I can’t remember if I used an adapter. Pretty self explanatory there. Stock wiring sends the signal to the cluster.

Water temp can go a couple of ways. Since the LS computer needs a water temp input you either need to run two senders or on sender that has dual outputs. The typical source for the single sender would be late 4th gen f-body Camaro/Firebird. One terminal feeds the ecm, the other feeds the cluster.

The two sender option is a little more difficult. A stock squarebody temp sender has a much larger hole it threads into the head. Those threads are sae pipe too. The ls has a smaller hole in each head with metric pipe thread.

I had a buddy take a new squarebody sender and turn it on his bench lathe and recut the threads to metric. It let me run one sender per head and I didn’t have to alter the stock wiring under the hood to make it work.

The speedo is the more challenging issue. You need a vss sensor on the t-case output to start. Not sure what t-case you have but the 241-c is the natural choice as that was the more commonly used t-case with the 90-91 electric speedo squarebody. A 90-91 205 is the other factory option but insanely rare.

If you have a cable speedo output 205, 208 or 241 you can convert them to vss with parts from one guy.

The factory 90-91 wiring for the vss signal is simple. Wires go from the vss sensor to the DRAC (digital ratio adapter controller) module. The drac adjusts the signal based on axle ratio and tire size and then distributes the signal on separate circuits to the cluster, ecm, cruise and abs.

So replicating the 90-91 setup is fairly straightforward, but you do need to snag a drac module and alter it to adjust for your tire size and axle ratio. It’s smart to get the harness for the drac from the truck you took it from. From the drac you can use the ecm circuit to ls computer for the transmission controls. Though I’ve heard of guys eliminating the drac and putting the signal straight to the ls computer and running a circuit from the ls computer to the cluster.

You are at a disadvantage with a damaged printed circuit on the cluster though. Not easy to come by. Since the one you have is missing mount ears I’d just look for another cluster and save that one for parts.
 
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I thought LMC Truck had replacement printed circuit boards?

Dakota Digital I hear is one of the better ones as far as replacement OBD gauges.
 
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jfkelley said:
I emailed them on Thursday and they stated that is one they don’t stock …
Click to expand...
Yeah, I wouldn't hold my breath for them coming around to having them at any later date. Even if you lump Blazers, burbs and 1-tons built over 90-91 with a total build quantity that is much less than the years prior.
 
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I vote for hardwiring. It's not THAT tough.

"Hard-wiring" stock instrument cluster

Edit: Sorry, links all died, here are the photos in no particular order: http://s831.photobucket.com/user/dyeager535/library/Truck/Cluster%20hard%20wire-LEDs%20C-K-R-V%20trucks%201973-1987%2091 If this is of interest to you, bookmark it, I will just add photos/text to this post as I progress...
ck5.com ck5.com

If you are need photos or more info I may be able to dig them up. Photobucket has been dead awhile I think lol
 
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The one big hassle with a 90 to 91 set up is the speedometer and odometer. The speedometer has it own small circuit board that receives input from the DRAC, and the odometer has a small step motor that always go bad, and are very hard to find.
 
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dyeager535 said:
I vote for hardwiring. It's not THAT tough.

"Hard-wiring" stock instrument cluster

Edit: Sorry, links all died, here are the photos in no particular order: http://s831.photobucket.com/user/dyeager535/library/Truck/Cluster%20hard%20wire-LEDs%20C-K-R-V%20trucks%201973-1987%2091 If this is of interest to you, bookmark it, I will just add photos/text to this post as I progress...
ck5.com ck5.com

If you are need photos or more info I may be able to dig them up. Photobucket has been dead awhile I think lol
Click to expand...
If you can find the pics send them
Over would appreciate it
 
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Mouser.com

Delphi (Now Aptiva IIRC) at the time had all of their catalogs online. Off the top of my head I THINK that I was using the 150 series connectors. ("16 terminal Delphi GT150 from my original post, that's what I used as the instrument cluster connector to body wiring harness replacement" ; "I used a four terminal metri-pack 150 connector assembly I found at the wrecking yard (available at Mouser too of course)"

I can dig into my orders on Mouser to see if I can find what the part numbers are if you need them.

It's been years, but I think they are all part of the metri-pack family. It would be quite difficult without the Delphi/Aptiva catalog to get the proper terminals to go with the connectors. I probably have those catalogs downloaded too, I tend to do that as manufacturers like to remove data that can be useful for those of us who pick something and stick with it over the years.

I believe Waytek sells some of this stuff too. Pretty sure my cheap wire crimper came from them. Actually works pretty good for crimping most anything I've run across so far, but as the wire gets up around 12awg the terminals aren't a real good fit. But for occasional use, the $20 I paid was worth it. Awesome to make crimps that you can't tell from factory.

BTW, I added pics I just took of the back of the instrument cluster to the album shown in the above post #10: https://ck5.com/forums/threads/stock-gauges-on-ls-swap-opinions-wanted.348135/#post-4309838

After 10 years of operation lol. I did go back after the initial build and glued a multi-LED bulb to the inside of the cluster to better illuminate the lower left side of the speedometer. Similar design as the 194 LED replacements I used, except not in a socket. I don't like bright clusters at night, so I fixed the PWM dimmer at quite a low setting, and that resulted in poor lighting at that location, so I fixed it.
 
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dyeager535 said:
Mouser.com

Delphi (Now Aptiva IIRC) at the time had all of their catalogs online. Off the top of my head I THINK that I was using the 150 series connectors. ("16 terminal Delphi GT150 from my original post, that's what I used as the instrument cluster connector to body wiring harness replacement" ; "I used a four terminal metri-pack 150 connector assembly I found at the wrecking yard (available at Mouser too of course)"

I can dig into my orders on Mouser to see if I can find what the part numbers are if you need them.

It's been years, but I think they are all part of the metri-pack family. It would be quite difficult without the Delphi/Aptiva catalog to get the proper terminals to go with the connectors. I probably have those catalogs downloaded too, I tend to do that as manufacturers like to remove data that can be useful for those of us who pick something and stick with it over the years.

I believe Waytek sells some of this stuff too. Pretty sure my cheap wire crimper came from them. Actually works pretty good for crimping most anything I've run across so far, but as the wire gets up around 12awg the terminals aren't a real good fit. But for occasional use, the $20 I paid was worth it. Awesome to make crimps that you can't tell from factory.
Click to expand...
https://ibb.co/DptT394

I been looking for this connector for weeks with no luck ..
 
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It depends on which gauge IIRC.

Do you still have the flex circuit? As long as you can still follow the traces you can figure out which is which. The + and - traces should be stamped into the copper near the IP connector area.

And looking at my pictures realt quick, I can make out where the +/- were marked either by factory, or me.
 
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