Dakota Digital HDX Install Write Up

[Old77]

Below is a detailed write up of installing the Dakota Digital HDX gauge cluster in a 1990 Suburban. The information is based off of what I did to accomplish the install and the things I learned along the way. I'm sure there a few other ways to accomplish this and I'm sure I did some things different than some of you would have done. That's ok

The first thing I did was start under the hood and get that taken care of before doing anything inside of the cabin of the vehicle. We need to replace the coolant temp sensor, oil pressure sensor, tap into the tach wire and some will have to also install a speedo adapter on the side of the transmission.

Coolant Temp Sensor
The Dakota Digital instructions tell you that the best place to install this sensor is on the intake near the thermostat housing. This may work for some earlier model squares but some folks smarter than me pointed out why this was not ideal due to ECM reading from that sensor and that the gauges actually use the sensor that is on the driver side head. With all of these sensors DO NOT FORGET TO USE THREAD SEALANT when installing them.

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Oil Pressure Sensor

There are a few choices for the oil pressure sensor. Inline, stock location or at the oil filter adapter. After much internal debate I went with the adapter direction.

Pic of original oil pressure sensor. To use this location at the very least you'll have to remove the distributor cap to get more room to remove the old sensor but most likely have to remove the distributor completely

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Here's where I ended up putting my sensor

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[Old77]

Tach Wire

On TBI trucks, the tach wire is this guy near the distributor (circled in red)

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The original connection was corroded so I snipped it off and soldered in my new wire

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Ran all the wires into the cabin. Per the instructions keeping the tach wire separate from the other wires as much as possible. When going through the firewall, use grommets to avoid wearing on these wires and causing issues in the future

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[Old77]

Now that we're done under the hood we move into the cabin.

Before doing anything study the wiring diagram specific to your vehicle and map that to the brain box of the gauges

Instrument panel wiring diagram for a 1990 Burb

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YOU CAN FIND THESE RIGHT HERE ON GMSQUAREBODY. Go to this link and OP has provided Wiring Manuals in PDF form for 73 - 91 squarebody trucks!! An invaluable resource. Follow this link

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

Old gauges

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Removed

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If you'll notice in that pic, to the lower left there is a "ground hub". This will come in handy as there are a couple of items that need chassis ground (i.e. fuel, DD computer,...)

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One point of clarification I want to make as there was some debate about it leading up to the finished product is where to grab the speed signal for the speedometer. For my rig, I was able to grab the signal from the speedo wire in the instrument panel harness (refer to the wiring diagram earlier in this post). Some people have chosen to pull this from the VSS and whatnot but for 89-91 trucks you can simply pull this from the speedo wire in the harness.

 

[Old77]

Finished pics

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[SquareRoot]

Good job. Your going to love them! I have had mine in for a couple years now. My only complaint is that the mounting tabs had all broken the last time I took the dash bezel off. I don't know if the resin material they use is too brittle or what. I wasn't going to send it back to have it replaced with the same thing. I ended up reattaching them with epoxy and making thin sheet metal "patches" to reinforce them. That seemed to fix it.
I also have the optional dimmer switch for the LED backlighting. I just mounted it below the regular dimmer switch. I like the ability to adjust the brightness rather than just having the on/off function. It wasn't until I installed my Edelbrock PF-4 EFI that the true capabilities of the gauges became apparent. When connected via the busbar, the gauges will display every operating parameter of the EFI ( A/F ratio, Air Inlet Temp, Vacuum, Fuel Pressure, etc. ). It's marvelous! You can also do things such as set warning when maintenance is due based on miles or engine hours, predict miles until empty for fuel....
But I digress, thanks for the post. Enjoy your new toy!

 

[bluex]

Looks great man! Glad you got them in an great job on the write-up

 

[Nasty-LSX]

Awesome man. Great write up. I'm so happy with my RTX-HDX. You will be to,
So many options for displays and color scheme. It will take some time to play with.

 

[Old77]

Thanks, guys

 

[ReefkoiC10]

I wish the mounting tabs weren’t made from the most brittle plastic known…that said they still stay in place but its annoying for an expensive kit

 

[55_2_Drive]

Nice, detailed write-up. I'm sure it will help lots of folks - some of whom might think installing the DD system is too hard for them. I put DD VHX in my 55 chevy and when I get to that point I will go with DD for my '76 GMC K20.


Not cheap, but great product that looks and works awesome. And really not hard at all it install (IMO).

 

[Old77]

Nice, detailed write-up. I'm sure it will help lots of folks - some of whom might think installing the DD system is too hard for them. I put DD VHX in my 55 chevy and when I get to that point I will go with DD for my '76 GMC K20.


Not cheap, but great product that looks and works awesome. And really not hard at all it install (IMO).

Not hard at all. Just gotta pay attention, get the details right and not rush.

 

[ChuckN]

Very cool man, nice job on the write up

 

[gmbellew]

Are you going to reuse the stock gear indicator?

 

[Old77]

Are you going to reuse the stock gear indicator?

Gear indicator for what?

 

[SquareRoot]

Gear indicator has nothing to do with the gauges.