My IPC bench tester project.

Alfa-Norway

Member
My project is a bench tester for instrument panel. After a long investigation of what I need, I set off. The first thing I needed was a PCM and a BCM. The PCM was from a GM Express wagon 2003 mod and the BCM was from a Tahoe 2004. And since they are from different cars I found that they had to be programmed so they could talk together. Good thing I have a Tech 2. But I have to do that later, after I have installed wires in PCM and BCM.
Since I recently started, I will come back with more as the project progresses. Sorry for my english I am after all Norwegian.:2thumbsup:PCM-BCM.JPG
 
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Alfa-Norway

Alfa-Norway

Member
Assembly of wires for PCM and BCM. Pot meters are also connected. tomorrow I will program the two PCM / BCM with tech2. Hopefully. I also got hold of a pulse generator for speedometer and tachometer since it sends vss signal to instrument panel. A cheap one from china. By the way my coffee cup in the back is from 1994 OL Lillyhammer:2thumbsup:

DSC_0348.JPG
 
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Alfa-Norway

Alfa-Norway

Member
Connected tech2 and pc for programming (sps) Since I have a Tahoe 2004 standing in the driveway I took a copy from it and put it into the PCM / BCM. Had to try and fail a few times before it went right.


DSC_0352.JPG
 
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Alfa-Norway

Alfa-Norway

Member
Then i decided to test if I got the pulse generator up and running after the data line worked with PCM / BCM. And to my surprise it worked! it is connected directly to the instrument panel so I didn't really need to have PCM / BCM connected.
Here is a picture of my puls generator test . i think its the first and last time it goes to 120 km !

ipc puls 120 km.jpg
 

MRRSM

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Velkommen til GMT Nation

Mange takke skal du ha...

Any chance for some Connector Pin-Out Diagrams for your Complete Benchtop Harness Set Up?


Ja, vi elsker dette landet ...

 
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Alfa-Norway

Alfa-Norway

Member
Have been a little busy to make a box that I can have everything in. After some time at the drawing board I came up with a solution almost looking like this.

Prosjekt boks.JPG
 
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Alfa-Norway

Alfa-Norway

Member
Thought it would have been fine and see if the steering wheel buttons also work ( DIC ) So I made these which are connected directly to B4, B5, B6, and B7 on the ipc connector. Black is ground. They will be mounted on the box.
 

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Alfa-Norway

Alfa-Norway

Member
Designed a pcm in inventor and marked pin placement of blue and green connector.
Have also run a pretest, found out that i need to add an on and off switches on ignition and pulse generator.
But the project is moving forward and it is nearing completion.
Now it's almost Christmas time,I'll be back over New Year.
Wishing everyone a peaceful Christmas and a happy New Year.


PCM blue.jpg

Backside of connector.

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Backside of rigg.

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DSC_0392.JPG

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MRRSM

Lifetime VIP Supporter
I'm guessing you will install (2) pieces of Aluminum Angle Iron ...back to back on either side to act like Slide Racks on your Way Cool & Well Designed "Norge IPC Test Console" and be able to vertically slip the IPC Unit using its Wide Plastic Housing Flanges down inside of them and hold the IPC up like a Laptop Screen?
 
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Alfa-Norway

Alfa-Norway

Member
Yes the thought has struck me. Think it would have been nice. One thing I have trouble with is the voltmeter. All gauge works except voltmeter. I'm not sure where I need to plug in the potentiometer and get it working via the data line. It needs more research.
 
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Alfa-Norway

Alfa-Norway

Member
Not happy with the Potmeters, they seem a bit unstable. May have to buy some new ones that are not as cheap as the ones mounted in the panel now. Need an extra anyway, for voltmeter gouge.
 

MRRSM

Lifetime VIP Supporter
It has been said...

"Ten Thousand Swedes... Ran Through The Weeds... Chased by ONE NORWEGIAN...!"

So I've no doubt you will "scare" up a Good Solution. :>)

I am not sure if you can use any of this information... but in a parallel (but as a Much More Primitive) effort to your present successful design... After watching this Dude's Video... I worked out his Wiring Diagram between the 24 Pin Harness Connector and the J-1850 OBD2 Connector.

The thing is though... I was designing this strictly Bench Top harness to work with IPC-to-Tech-2 Quality Hand Held Scanner set ups versus having a Dedicated Apparatus for the PCM-BCM-IPC set up like yours.... and so it may NOT have the capability of actuating the TACH and SPEEDOMETER in the absence of a separate Signal Generator fed into the correct 24 Pin Connector at the Right Pin Points. Anyhow... Here is what he covers:


This was my reaction to his Video:

Once again... I'm back with what I consider to be A VERY BIG DEAL in the way of How To Make A Dedicated Bench-Top Instrument Cluster Bi-Directional Electrical Test Harness that will work with ANY Scanner that has the BI-D Capabilities. FINALLY... Somebody in the GM Instrument Cluster Repair Business has taken the time to decipher the GM 24 Pin Cluster Connector interface to the J-1850 Female OBD2 (Auto Chassis Under-Dash) Connector.

Armed with this information ...and if possible... First obtain a Junk Yard Instrument Cluster Harness Plug with a Goodly Length of the OEM Harness Wires still attached:

REMEMBER... The PIN Orientation of the 24 Wire Instrument Cluster PLUG is LEFT to RIGHT ...if the Harness Wires get DIRECTLY attached to IT ...as opposed to attaching Individual Pin-Wire Connectors DIRECTLY to the Instrument Cluster 24 PIN Connector on the Board...as seen in the attached Video and has a RIGHT to LEFT Orientation and therefore... they are BACKWARDS to one another when Viewed Face On, side by side!

Then... you can wire either arrangement into the inexpensive J-1850 OBD2 Female Port and AFTER you Repair the LEDs, Mosfets and Dials on these GM Clusters... plug in either arrangement and Power Test the Lights and Dials... right there on your Bench. Yeee Haaaa!

So now... If you have your very own "GYMKO" Tech 2... So much the better for being able to run the actual Diagnostic Checks and Powered Bench Tests as though the Re-Built Cluster(s) were still mounted into the Dash Boards. I would recommend Downloading and saving this Video to obtain accurate Screen Prints of this Dude's Hand Drawn Wire Diagram of this Harness ...before his competitors find some way of getting this Video Deleted.

The Important Thing To Remember is... If you will be using this Cluster Bench Test Harness with any Tech 2 Clone... you MUST Insert the Tech 2 (12 )VDC - 1 AMP Power Supply Plug or Cigarette Lighter Power Cord Plug ...into the Male OBD2 Tech 2 Adapter...and NOT into the Base of the Tech 2 ...otherwise, the IPC Cluster will NOT Power Up:

Okay... To save everyone some time on this and memorialize the actual harness connection layout...

I worked out all of these 'Visual Clues" into how the GM 24 PIN Instrument Cluster communicates with the Female OBD2 Port Connector (J-1850) with the Caveat that if you will be using a USB Blue Tooth Adapter... You will need an External Power Supply producing 12 Volts DC @ 1.389 Amps to connect the Three Wire from the 24 PIN Cluster Connector B+ Connectors over to PIN 16 for the Positive 12 VDC and then arrange the A12 and B12 Pins from the IPC Connector over to PIN 4 of the J-1850 for GROUND. This is NOT necessary to do when using the "GYMKO" Tech 2 Scanner:

Positive (3) Wire Bundle 24 PIN Cluster Connections:

Positive Power 12 VDC Wires
A11, B9 & B11

To… The J-1850 OBD2 Female Connections:
PIN 16 B+

Ground (2) Wire Bundle 24 PIN Cluster Connections:
A12 & B12

To... The J-1850 OBD2 Female Connections:
PIN 4

Class 2 Data Connections 24 PIN Cluster Connection:
A6

To… The J-1850 OBD2 Female Connections:
PIN 2


Last edited: Apr 25, 2019

 
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Alfa-Norway

Alfa-Norway

Member
My tack an speedometer runs fine as the puls generator is connected direct to the 24 pin connector in the ipc. One thing I found out, when i connected the pulse generator on the same 12 volt circuit as PCM and BCM the speedometer started up and went up to 80 km and would not be adjusted. It needs its own on and off switch. If i turn it on after PCM and BCM have bootet it works fine. Dont ask me why, i have no clue. :dunce:
 

MRRSM

Lifetime VIP Supporter
FWIW... I'm thinking it could be something like "The Ghost in The Machine" phenomena at play here. For example, it might be that with your PCM-BCM-IPC Set Up (all and singly) the system could be acting like a Soldier with an Amputated Leg ...suffering from "Phantom-Lost Limb Syndrome".

After all... there may be some passive Module polling-sensing going on while the two "Brains" are powered up and constantly looking for Inputs and Output from ALL of the Absent Modules on the Single Wire Class 2 Network. Perhaps you could use your Tech 2 to "Ping All Modules" and see what the responses are as soon as you flip the Remote Switches to Power Up the TACH & SPEEDO Potentiometers. Having a DMM set to DC Volts and connected to that Low Power Circuit could be revealing as well while observing for the occurrence of any Power Fluctuations.

You well know that ordinarily, all the Modules tend to reside on that One Wire and communicate using anywhere between 0-7 Volts DC and try to get along with each other via varied Pulse Width Modulation. But we all know that weird things can and have happened "In Situ" within the GM-GMC Trucks and SUVs when one Module is 'Misbehaving' and having some 'Odd Sideways Affect' with some of the others residing on the Common Network.
 
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Alfa-Norway

Alfa-Norway

Member
Thank you for your reply, I will connect Tech2 and " ping " all moduls. Earlier when i had connected all with Tec2 it could not see the ipc. I will try to reprogram pcm with the ipc again.
 
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Alfa-Norway

Alfa-Norway

Member
Regarding voltmeter gouge that I have not got to work, somebody has an idea how to connect the potentiometer and make it work. I Add picture of charge wiring diagram.

lading voltmeter.jpg
 

MRRSM

Lifetime VIP Supporter
Based upon the Electrical Schematic Diagram you posted... it makes sense that there would be NO VOLTAGE READOUT on the Voltage Gauge because the information involved is ordinarily provided by the Alternator Rectifier Circuit and then fed into the PCM for Signal and Duty Cycle processing FIRST and then it gets sent out on the Dark Green Wire to the Splice Comb and picked up by the Class 2 Network GRAY wire as PWM leading to the IPC 24 Pin Connector. No Alternator? No Voltage Reading! It's Pulse Width Modulation that changes the position of the Voltage Gauge Readings on the IPC under PCM Management... NOT the direct measurement of variations of Low Voltage Direct Current.

With all the design and build responsibilities that come with your having such a Creative Mind, sometimes it can lead The Inventor to have temporary 'Tunnel Vision' and to overlooking the need to Back-Track and Re-Examine the IPC itself. Your images show that you have (2) IPCs available as your Test Subjects...

So... Try Pulling the IPC Back Covers off of them both and then Examine and Re-Solder or Replace the MOBO Connections for the Voltmeter Stepper Motor(s). if either one or both Stepper Motors turn out to be Bad, you might be imagining problems with your New Design that do not exist within your Device. You could wind up Testing and Working on everything else before you take a closer look at the Absence of any Needle Swing on the Dashboard Voltmeter Gauge itself. I've had problems like this happen to me more times than I can count. I hope that THIS turns out to be the source of the issue.

One other thing is that since you are using the P-59 PCM-ECM (BLUE-GREEN) from one type of GM Vehicle and the BCM and IPCs come from other types of GM Vehicles, it would be helpful to know whether or not they are able to share Common Wiring Diagrams with your Test IPC Units. If not, this may be causing confusion as to which of the 24 Connector Wires are relevant to either one PCM and BCM .BIN configuration or another. If these items are all on the same page... please advise which particular Vehicle Make-Model-Series you finally decided upon and post that information back here:

2013-05-17_134312_clust.gifls pin diagram.jpg

This is going to sound a bit crazy... and a lot like some "Rube Goldberg" sort of Mechanically Clunky Idea... but in lieu of using the Electronic Signal Generator to Test the Tachometer and Speedometer... perhaps you could wire in an Actual VSS Sensor with a (2) Wire Harness Metro-pack Connector and then place or mount it next to a Small, Variable Speed Electric Motor (or a Dremel Tool) in close enough proximity to pick up the rotations of a wheel fitted with a small Gear, Fan or a Cylinder.

You will need to be able to accurately calculate what the Transitional Velocity of the Outer Edge of the Gear, Fan, Cylinder is turning at, based upon how large its Outside Diameter has to be to accommodate just the right number and spacing of the "Reluctor Ring Teeth" in order to make this idea work.

With teeth or grooves cut into it like a Reluctor Ring with Steel Metal Tape segments to trigger the Hall Effect, once this thing is Scaled to Convert 4,000 Pulses Per Second for each 1 Mile Per Hour to be shown on the IPC, then you could see how the PCM-BCM-IPC read-outs appear on the SPEEDO Gauge based upon variations in the Dremel Tool or Small Motor RPM. The attached image illustrates this Mechanically instigated Hall Effect "Square Wave Generation" Principle in action:

HALLEFFECTSENSOR.jpg

That same idea would apply for achieving "Real World Tachometer Conditions" using a wired-in Crankshaft Position Sensor (CKP) with a similar requirement of having a Small Electric Motor Driving a Reluctor Wheel adjacent the "CKP" Sensor after knowing how many times it needs to get Pulsed via the Hall Effect to accurately determine the RPM of "The Engine" based upon how fast that Dremel Tool or Small Electric Motor is turning the "CKP Reluctor Wheel" :>)

GMVSS.gifGMVSS1.gif
 
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Alfa-Norway

Alfa-Norway

Member
I have studied the charging diagram many times and thought that solution must lie there. But as the amateur I am, I haven't found the solution yet. But you're in for something there.
When it comes to car type PCM is from a GM Express van and BCM comes from a Tahoe 2003, they are both programmed from my Tahoe 2004 (Copy from my car)
I am not very good at electronics, I am a trained plumber and tig welder, and technical drawing. I appreciate what you write and I will study what you write more closely.
Thanks mate.
 
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Alfa-Norway

Alfa-Norway

Member
I don't think it matters if Ipc comes from another car but I might be wrong. Have seen youtube videos of a guy using the same benchtester on different ipc`s. I post a picture of the serial data chart taken from a 2004 Tahoe.data link.jpg
 
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Alfa-Norway

Alfa-Norway

Member
So you think I have to have some kind of pulse generator to get the voltmeter gouge to work?
I have read this one a place, dont remember where:
Integrated systems use a battery current sensor to provide
a body controller (BCM) the amount the battery is charging or discharging.
Accurate voltage measurements are taken through
the battery positive voltage and ignition 1-voltage circuits.
The BCM then communicates information over serial data circuits for the ECM/PCM to directly control the generator.
 
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Alfa-Norway

Alfa-Norway

Member
And this:
The RVC system allows voltage changes, up or down, based on battery state-of-charge,
the vehicle’s present electrical needs and other factors, so the voltmeter reading may fluctuate.
Conventional systems usually maintain a consistent reading of around 14V.
The RVC system voltage may range between 12 and 14V. This is normal system operation,
but may be perceived as a problem by vehicle owners who are accustomed to seeing a relatively consistent voltmeter reading.
There are two types of RVC systems in use—integrated RVC and stand-alone RVC (SARVC).
Integrated systems use a battery current sensor to inform a body control module (BCM) how much the battery is being charged or discharged.
SARVC systems (found mostly on trucks) do not use the BCM for operation.
They have a generator battery control module mounted to the negative battery cable,
to interpret battery current and voltage and battery temperature inputs.
The battery current sensor is internal to the module.
This module also directly controls the generator L terminal duty cycle instead of the ECM/PCM.
 

MRRSM

Lifetime VIP Supporter
Yes... But only after confirming that the Voltage Gauge Stepper Motor on the IPC is functioning properly. You have Three Possible Ways of approaching this issue:

(1) Set up a 12-15 Volt DC Generator that filters through a Compatible, Solid State Voltage regulator like the one mentioned in your Schematic... and then send that Output into your P-59 PCM via the Correct Connector Pins. Then read the Output from the PCM on the IPC Voltage Gauge being actuated via the PWM on the GRAY Wire Class 2 Wiring-Pinouts Input.

(2) Use a Pulse Generator that outputs the correct PWM into the 24 Pin IPC Connector via the Correct 24 Pin Wires-Grounds servicing and actuating the IPC Voltage Gauge Stepper Motor.

(3) Use a Tech 2 via the OBD2 Interface to the P-59 and BCM to Command the "Sweep Gauges" Feature of the GM Tech 2 Diagnostics Features...and observe the behavior of ALL the Stepper Motor Sweep Hands of the IPC.
 

MRRSM

Lifetime VIP Supporter
Technically Speaking... Once you've seen that ALL the Stepper Motors perform Nominally... it really is NOT necessary to create any sort of 12 VDC Generation-Reading on the IPC Voltage Gauge. It is either WORKING properly as a Stepper Motor should ... or it's NOT.
 
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