Instrument Cluster Changes '99-'04

[AaronGTR]

Yeah, I know the VES goes through the EBCM for sure. As Mark said it uses the wheel speed sensors and steering angle sensor to determine what steering effort should be. IE change in vehicle speed will change the steering effort. I found this out on my GP as well, as I did some engine repairs once and the ABS, Trac off, and brake lights came on after doing the work. Problem ended up being the plug on the steering pump wasn't in all the way, so the EBCM thought there was a problem.

[The_Maniac]

I just expanded my research about the EBCM. Looks like from '99-'05 GM used 2-3 different EBCMs!! And they are completely different (connector and how they install).

I looked up the EBCM for a '04 Grand Am and compared it to an '04 Monte (as I know the Monte/Impala have a tire pressure monitoring system). Per the shop book, the connector shapes and replacement procedures for the '04 Grand Am and '04 Monte/Impala are the same. This suggests the same hardware, different software (the difference being software to calculate tire pressure).

I compared the pin outs and the two are near identical. Perhaps in the spring, I may pull a junk yard '04 Monte/Impala EBCM and see what happens if I plug it in on my Grand Am which I now have a Tire Pressure light wired in). It's a plug and play swap, no Tech2 adjustments required.

For now, it's simply crazy talk, but I wonder if that is the missing link to this puzzle is an EBCM that actually does operate the tire pressure system.

Since I've been casually look at this stuff, I find it interesting:
- Between years of Grand Am, I have seen various Instrument clusters that had revised circuit boards. In each, GM kept the traces and pathing for the Tire Pressure Light.
- They changed the EBCM about three times in this generation Grand Am.

It makes me wonder if they intended to re-offer that feature and just never did it.

[plastic_indian]

One can never tell, but more often than not Wagoner-era GM decisions - be it revision or consistence - were founded more on immediate cost savings rather than foresight (personal observance; no quantifiable analysis). In short, the VLE running the Grand Am program probably had his/her wings clipped with regard to redesigning any viable preexisting electronics; creature features were an Oldsmobile selling point (affordable luxury) and the Grand Am was marketed to lower midlevel middle aged women (WTF does that say about us?), so the TPM circuitry in the IPC may be vestigial or otherwise present only by virtue of is utilization in the Alero.

Speaking of, just swap in a TPM Alero EBCM to answer the software vs hardware question.

To dig deeper, pose the question to the GMECM/DIYEFI mailing list. They are more about adaptions of the 727/747 ECMs to projects all over the spectrum, but those guys are absolute Ubergeeks when it comes to hardware hacking. If nothing else, membership on the (admittedly slow the last few years) mailing list will open one's mind to the things that can be cooked up at home with sufficient patience, persistence and oxyacetylene.

[Pontiac_guy99]

I always enjoy reading this thread - I like the electrical/technical parts of cars. It is pretty neat how you are doing this.

[The_Maniac]

Originally Posted by plastic_indian

Speaking of, just swap in a TPM Alero EBCM to answer the software vs hardware question.

I suppose the question is, did the '04 Alero have a tire pressure monitoring system? Because that's the EBCM I would require (as the EBCMs in the Alero changed with the Grand Am according to the shop book data). Looking at the shop book, it appears the Tire Pressure Monitoring system does not exist in an '04 N-body car (but does in the W-body).

[The_Maniac]

OK, here's some more information of interest about the Tire Pressure System.

So my father followed the traces and I mentioned we wired some components in (I soldered the LED ).
Here's what is required for the Tire Light:
- Add LED to DS17
- Add Resistor to R56 (we did not have a 510ohm Resistor, like we did for the cruise light, so dad used one that was close)
- Add Jumper to W30

Now my problem is, testing the light. I've powered up GM clusters out of the vehicle. They honestly do very, very little without a system commanding them to do something (they might power on test your turn signal lights and that's it, they need the rest of the computers in the car to power on test the idiot lights and gauges). That being said, I have been at a loss for how in the heck do I test this Tire Pressure Light???

Got my answer. I got access to a GM Tech2 tool. It would not let me test one light (it was all or nothing). But it lit up the Tire Pressure light (seen in the attached pic). It also lit the shift light (which I have an automatic, but hey, it works).

So, this tells me the reason the light does not respond to anything is because the cluster is not yet commanded to do anything to display the light.
This brings me back to the software in the EBCM. So hopefully in the spring I will swap the EBCM with a Monte or Impala unit, just to see what happens. My hope is that the software in the EBCM is compatible with the Grand Am.

Figured this discovery was worth sharing.

[AaronGTR]

Where is there a shift light in the cluster? Curious because I've never see one.

[bricooper78]

with light in the right spot, there is an up arrow (that GM cheaped out and used in cars instead of a tach) on the tach side of the GA dash, but the light has to hit it just right, you can see the cut out and shiny arrow

[AaronGTR]

Interesting. I'll have to shine a light on mine and see if I can spot it. I'm curious now.

[bricooper78]

i THINK it is above the 6 is it at yellow line? or was that 5? But I'm thinking that's where it was.

been quite a while since I've seen that dash, but my 01 had it

[The_Maniac]

Below is a pic of my full cluster (showing the shift light).

There is a low oil light that is non-functional on my '04 (no bulb for it). I'm sure I could resurrect that one by adding missing components to the board and a oil switch to the oil pan. Since my pan does not have the holes for the oil switch, I'm not going to mess with that one (but I believe the connector is already in the car for it, as I have a dangling wire in that location that looks like the correct plug). The oil switch just goes to one pin on the PCM and the other side to ground.

[AaronGTR]

That's cool man.

Yeah, I wouldn't think there would be much point in adding the oil level sensor. On mine it's in the bottom of the pan, in kind of a recessed spot, and if the oil got that low I'm pretty sure it would get below the level of the oil pickup and the oil pressure light would come on. Maybe not though. I suppose it's possible the switch is just above the height of the oil pickup at the bottom of the pan. If it got that low though I would also think any oil slosh during cornering would make the pickup suck air and the oil pressure light would flash on and off. Of course at the point that happens, you'd probably already be doing engine damage from loss of pressure.

I guess that's why GM decided the oil level switch was redundant and eliminated it?

[The_Maniac]

Actually the low oil switch works fairly well. The pan is the same design the 94 grand am had with the 3100. In my experience with oil leaks on the gen, when you get about 2 quarts low, the light will trip and you will still have enough oil to maintain pressure.

But I am guessing gm decided to ditch it because most people notice oil stains on driveways and parking lots and eventually like you said it will trip the low pressure warning.

I'd like to add it, but I'm not swapping the pan for this one. Too much work and annoyance.

But if some one needed a low fluid light for something else, you might be able to reuse this .

[bricooper78]

I'm pretty happy I got the 5 right... kinda

[datashifter]

Sorry for the dusty thread bump...

Have you made any further developments pertaining to the Low Tire Pressure Monitor, Mr. The Maniac?

I own a 2003 GA and have a 2003 cluster arriving in the mail today for tinkering without mucking up my presently installed and working cluster. I had a 2000 Grand Am back in the day and I have missed the CC light, however I'm very happy to read that with the addition of an LED and 510 ohm resistor I can get that friggin' light back! I would also love to get the low tire pressure indicator working - that is a feature I never had but would appreciate.

I am also wanting to tinker with using different colored LEDs in the IPC. Over the years I have become a little tired of the red throughout the IPC at night, so I'm pondering using an Arduino to drive RGB LEDs to select whatever gradient color I wish for the IPC backlight.

I also want to look into changing the OEM red stereo LCD to another color (I believe they used a red filter with white lights behind it) and would also like to change the odometer color (mayhaps they used another red filter there), and they quite possibly would be controlled by the same Arduino driving the RGB LEDs for the IPC backlight. Why haven't I changed to an aftermarket head unit? Simple answer...my XM radio has glitched somehow, and now I have free XM radio service!

Another thing I plan on hacking away at is reprogramming the mileage on the soon-to-arrive IPC so I can have accurate mileage. I plan on making all the changes to the new-to-me unit and dropping it into place once I'm finished. As such the mileage would likely be the last thing I hack away at. However, I am great with electronics troubleshooting/repair and feel quite confident the mileage is stored in an EEPROM chip which can be reprogrammed with the right software and a good old RS-232 serial port interface.

So, any updates with the TPM? :-D

[The_Maniac]

Unfortunately no "real" updates on the TIM system (the Grand Am called it "Tire Inflation Monitor", yet all other GMs was a TPMS, weird).

What I CAN tell you, I have a resistor and an LED wired into the board (same deal I had to do for the cruise light). But there is NOTHING to command it to do anything, so it never activates. I did post earlier, if I use a diagnostic feature on a GM TechII, that light for the TIM will activate (as seen in a pic I took). The assumption I make from this is that the light is functional and it proves can be commanded on (so more then likely the programming for the light in the cluster is still present).
What I believe I need to make the system function is an EBCM (Electronic Brake Control Module) that contains programming for the TIM system (the shop books for GM cars with a TIM/TPM system state the programming is in the EBCM). From what I've seen, I believe in '99-'03 GM changed the type of EBCM (hardware/connector/entire deal) about 3 times. For my '04 Grand Am, the connector matches the '00-'05 Monte/Impala (but the pin outs don't match).
Even though I have an '04 Monte, I am NOT pulling the EBCM from it to try this. I want to get one from a junk yard. Even though the pin outs don't match, I suspect there may be shared pins or I can make some adjustments in this process. Bottom line, plug the junk yard EBCM into the car, turn it on, see if the TIM system light does a diagnostic check. Next, try performing a reset of the TIM system (hence why I re-added the reset button for oil life and tire monitoring that GM had in the driver side fuse panel).

If you are feeling adventurous, wire in the resistor and LED for the TIM system as well as the cruise light. Next look up the EBCM for your Grand Am and see if GM has another car with a TPMS system (love the different terms ) and see if you can match the hardware (connector and type of unit, again you MIGHT have to mess with the pin outs to make it work).

One side note to be concerned of, changing the EBCM for one with programming for a TIM/TPM system, I do not know if that will affect the programming driving ABS or traction control.

[datashifter]

Darn, sounds like too big a pain to get TIM/TPM. Might have to write that off the list of things to hope for. I am not the mechanic type with access to Tech2 scanners, cross reference lists and such. It sounds like you're a lot more qualified for such activities than I am, and considering how much effort that would take I don't feel it would be worth it for me. All I can say is I have to look up to you and your knowledge concerning these matters...

I have begun with what I said I would likely save for last - adjusting the mileage in the odometer. I mean, why bother tweaking the used IPC if I can't calibrate the odometer?

I broke out my SMD hot air rework station tonight to remove the daughter board from the IPC and take a peek at it. I was not even going to try to solder-wick the 64-pins off the main board. Took about 10 minutes to remove it with hot air.

Found a few IC numbers on the daughter board but have not yet been able to locate any datasheets despite exercising my Google-Fu. Best I can tell, the odometer reading is most likely stored in what I believe to be an SPI Atmel EEPROM chip (surface mount SSOP/TSSOP 8) on the daughter board.

The ICs I found throughout the IPC were mostly Philips. What follows is a breakdown of the IC part numbers.

IPC Main board...
Philips (appears to be an LED controller chip), markings:
16221237
AB812
Un02482

LCD Odometer board...
Philips (LCD display driver chip?), markings:
16206747
79544
YS02341

Daughter board...
Philips chip (what is it for?), markings:
16180908
E7439 04
Un0251 1

Atmel chip (SPI EEPROM?), markings:
ATMEL 252
68343 C
2H4833

Texas Instruments (CPU or maybe BUS interface chip?), markings:
09356797
S10C4024FN
(C) 1998 TI
980 31A3KLW
F42

Unidentified manufacturer (no logo, no idea what it does), markings:
16226782
C225111 06
519 S FnR0244 B

I plan to unsolder the Atmel chip and query it, but I need to reassemble the whole shebang first to get the used IPC's mileage so I know what values to search for. I got a little disassemble-happy when I got home today.

I'm probably going to socket the IPC for ease of daughter board installation and removal because while it was doable, I don't want to have to unsolder that thing again.

[datashifter]

After giving it a thought, the "unidentified manufacturer" chip on the daughter board might be a controller IC for the stepper motors which drive the analog needles.

[The_Maniac]

I'm just a guy with some ambition and willing to try some out of the box stuff (and sometimes can leverage help from friends and family). I am fortunate to have access to a GM TechII and as for the shop book data, that's thanks to a disc from eBay (not sure if that's still around).

I looked at the control modules for the ABS system, that might not be a do-able option, it's a bit hard to confirm (as there are some differences on things). It would almost be curious since the EBCM is screwed on to the ABS pump, could I leave the factory EBCM, then run another set of wires for the ABS sensors to a Monte/Impala EBCM and some how leverage the second EBCM just for the TIM/TPM system.

This idea may get scrapped, but I really would like to try connecting a EBCM with that programming to the car and see can I make the TIM light activate during a start up diagnostic AND during a reset procedure. Again, there are a few challenges in the way to make this one work. And if it gets scrapped, not a big deal (I'm thrilled to have the cruise light active).

[plastic_indian]

An Alero EBCM cannot be used? The Alero iteration of the Gen V N car featured (or had available) WSS based TPM.