I'm thinking about making an aftermarket set of guages. I'm wondering, is it possible to wire the aftermarket gauges so It just plugs right in, so If I ever wanted to go back to stock, I can just plug the original cluster back in?

Nope. Most of the cluster info is transmitted on the UART data stream, then decoded at the microprocessor on the cluster PCB.
The speedo and fuel gauge are direct signals, but that's it. You have to run a tach line, a coolant temp line, and wires for any other gauges you want to use.

Thank quick.

Actually I think I can do it. I can get another speed sensor to wire the aftermarketspeedo into, and unhook the original so the pcm doesn't read a signal. I'll wire the tach straight to the coils or plug wire. I can use those snap splicers and a plug-in to wire in the fuel gauge so the original cluster plug stays there. Then I can add a second temp sensor for the aftermarket gauge, get an oil filter sandwich for the oil psi gauge, and make a custom harness to the engine bay to run the gauges. Does this make any sense to anyone?

yea i understand lol, just gonna be a pain and some splices? ha

yeah you have the right idea. i think you might want to leave the old cluster plugged in hidden away in your dash or you could run longer wires and put it anywhere. that way you can still know if you throw a code/check engine light...just food for thought

Michael Antle wrote:Actually I think I can do it. I can get another speed sensor to wire the aftermarketspeedo into, and unhook the original so the pcm doesn't read a signal. I'll wire the tach straight to the coils or plug wire. I can use those snap splicers and a plug-in to wire in the fuel gauge so the original cluster plug stays there. Then I can add a second temp sensor for the aftermarket gauge, get an oil filter sandwich for the oil psi gauge, and make a custom harness to the engine bay to run the gauges. Does this make any sense to anyone?

You can definitely make a harness for your gauges running your own wires, but your original post sounded like you wanted to wire them up to a plug to connect into your factory cluster plug.

lostsol, the CEL actually has it's own wire (the ECM grounds this wire to activate the light), so that's not necessary. You can easily wire up an LED or bulb to this wire.
IIRC, Kardain did that on his custom cluster.

Quiklilcav, I originally had intended to use the intrument cluster plug, but I know it's not going to happen. I'm going to create my own harness to the engine bay, with a handful of wires spliced into the stock cluster wiring with a plug for check engine light, high beam indicator, turn signal indicators, and the fuel gauge. Everything else will be wired directly to the engine. IIRC, I think I read here on the org that you cannot start/run the engine without the cluster plugged in? this true?

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IIRC, Kardain did that on his custom cluster.

that I did. Turn signals, brake light, high beam, and CEL are all independent from the serial data wiring

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Everything else will be wired directly to the engine. IIRC, I think I read here on the org that you cannot start/run the engine without the cluster plugged in? this true?

edit: if you are using the 2.2 computer & engine, yes. you will need to isolate the circuit board.



Edited 1 time(s). Last edited Saturday, January 19, 2008 1:22 PM

Kardain, am I on the right track here? Does this make sense to you?

fixed...

So Basically, If I run a 2nd gen computer and a 3400, I shoulld have no problems with the pcm not picking up that the cluster is unplugged?

Correct.

A suggestion for splicing into the factory harness, but I would get some Molex plugs or similar so you can easily plug the factory wires back together. You can get Molex plugs at Radio Shack. They come in various numbers of pins, so get one that suits your needs.

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A suggestion for splicing into the factory harness, but I would get some Molex plugs or similar so you can easily plug the factory wires back together. You can get Molex plugs at Radio Shack. They come in various numbers of pins, so get one that suits your needs.

That's the route I started with, but for some reason the 9 pin was being a PITA, so I pulled a 12 pin flat connector from my second gen parts car (somewhere in the steering column) and used that.

Or.... Michael, if you are ever at the junkyard, see what's there for various stereo/column/body harnesses (doesn't matter what make/model), you might find something for your intended application. Then its just a matter of splicing that plug in to your wiring.

What I'm planning on doing is using those snap splicers, that you put a wire into, and just snap it onto the wire you want to splice into. No cutting, taping, heat shrinking, or anything. Heres a picture:


I'll use those splicing things to get power from a cel, turn signals, high beam, battery light, and oil light, and the fuel gauge. they'll be wired to a plug and the rest of the gauges ran independantly, so if I ever want to go back to my orignal cluster, I just unplug the plug for the lights and tuck it away, unhook the VSS from the tranny and put the original in, and unplug the gauges inside.

I don't like using those, but they'll work ok.

Also, keep in mind that the CEL lead is a grounded signal, not power. You need to run power to your light, and connect the negative side to the CEL lead.

Also, you don't want to unhook the VSS from the ECM, because it will cause issues. What you need to do is to tap into the lead that goes to the cluster from the ECM (the speedo is not part of the serial data stream.)

Michael Antle wrote:IIRC, I think I read here on the org that you cannot start/run the engine without the cluster plugged in? this true?

I know for the 2200 you dont need it connected, the car will start and run fine. However for the other motors i am unsure.


Click Sig for Jersey GM's Official Website

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Also, keep in mind that the CEL lead is a grounded signal, not power

as is the high beam indicator

So for the cel and high beams, ground out the led and connect another wire into the cluster harness.

Also, for the VSS, It shouldn't cause issues if the pcm doesn't read a vss signal. I've unhooked mine several times and haven't had an issue.

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So for the cel and high beams, ground out the led and connect another wire into the cluster harness.

Hook up the power to a switched hot and ground to the indicator wires.

Yeah I got them mixed up again, lol

Kardain wrote:

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Also, keep in mind that the CEL lead is a grounded signal, not power

as is the high beam indicator

That too.

Strange GM decided to make those two a grounded control, but the turn signals a positive signal.
Gotta love the consistancy.