Bought the cluster hoping it was a plug and play and its far from it. I have quite a bit figured out other than what sensor I need to buy to get the temp/oil pressure gauge working and how hard it will be to wire this all in. Im doing as much research as possible before I start and was hoping someone could confirm that my wiring that I figured out using just the wire tape strips on the back of the clusters is right.

Also if anyone has pulled a dash out of one of these let me know how hard it was. I could get away with leaving the dash in but will be a pain to work around without removing it but if its not that big of a deal ill remove it to run my wires. Thanks.

If anyone has any information they could add to this please feel free to. I think I may just do the wiring for the fuel level and volt gauge till next summer when I can take the whole dash out of the car and wire it properly.

Top cluster is the stock one. Bottom one is the one im trying to wire in.


Here are the 2 (Left and Right) connectors I need to try to rewire to get the cluster working correctly.


Sketch I did of the wiring on the back of the clusters.


This is the stock cluster wiring that I think I have figured out.


This is the 5 gauge cluster wiring I think I have figured out.

I imagine they are wired the same in the car, just with different clusters attached. They did a lot of that back in the day. Maybe someone here has a diagram.

For oil pressure and coolant temperature you'll likely have to change out the related sensors from on/off sensors to analog sensors.

Please tell me that you're going to swap the calculator from old to new!

Dont worry the calculator will go with it. Check out this video I made if you want to see a ultra rare option as well as me swapping in the calculator.
They are wired completely different. I mapped out what the back of them looked like and the oil and temp gauge have a different wire as it retains the warning lights as well. Here is a picture of the wiring I drew up side by side. The left connector is almost the same other than the added ground. The right side connector on the other hand is completely different. I plugged in the 5 gauge one and the fuel level spiked well past full. If you look at the drawing the fuel level power is the 4th one down on the left and on the 5 gauge on thats the fuel level sensor wire. Im hoping to get a wiring diagram for the 5 gauge cluster just so I can be positive I wire it right. It will have to wait till next year anyways as the temps around here are getting in the 40'* and snow will be here soon.

Here is the back of the 2 clusters. The top one is the 5 gauge cluster and the bottom is the stock.

Having done swaps in the past, I was surprised that GM used different harnesses to the instrument cluster dependent on the cluster. Fortunately, they are easy to pop the pins out and rearrange them as needed.
I'm sure the digital cluster in these cars (I've only seen 2, my Grandparents bought one new) were wired differently as well. I powered up an '85 coupe last year in the wrecking yard to take a look at it. It had the voice command system too, so I got to hear it talk!

Yeah it sucks they are wired so different and I did pop one of the pins out and they are easy to get out but will be hard to rearrange with the little room they give me plus I need to run the 2 new wires for Temp and Oil pressure. Im going to go to a pick and pull and try to remove the dash to see how hard it is.

As for the talking car I have been looking for that module. Do you happen to have any information on them at all? Im trying to get all the odd options and thats one I can find very little info on. Seen 2 youtube videos but they were short and didnt talk about the unit more or less just it talking.

Yeah I can see the differences in the back now. Still doesn't look too bad, but you're right on track getting it all diagrammed.

My only knowledge of the voice system is that it is heard through the left front speaker. I only have the Olds shop manuals for the 1984 model year too, so no coverage of the 'new' FWD 98.
I really wanted to get the 'source' of the voice system for my own, neardy knowledge when I found one last year. Unfortunately, it was so close to the other cars, and being a coupe, it was really hard for an 'old guy' like me to do anything with doors that would hardly open. And it was HOT outside.
Since the Aux / Voice Input does not appear in the stereos until the big wiring harness style change with the 'CDM' stereos ('88 C/K truck at the earliest) and steering wheel controls, I have to assume that it is an external module that interrupts the inputs to the left front speaker.
If you happen to have seen the stereo from your cars and it has marking like this from the later stereo, please let me know. GM / Delco snuck a lot of capabilities in some stereos most people never knew were there.

Just knowing that it comes out the front speaker is good to know as I thought it might have its own speaker. Did you happen to watch my video on the CB radio? It does the same thing. Cuts out the driver front speaker when someone is talking on the CB and then cuts back to the radio and it does all of this without the factory radio and all in a stand alone unit.

Great video! I can't say that I have seen the CB option in a car that new, but it sure looks like it was designed for it. The silver part of the CB box and its brackets even look a lot like the 2003 - 2006 GM XM radio modules.
Glad I didn't spend the time trying to get at the voice module in the car I saw. Dash was fully intact and I could see the dash in the 98 (and 8 of that era took a lot to disassemble. I have a suspicion it is located in the same spot as your CB module.