Shazaam! 1995 Deville DIC instant "upgrade"

[Kdirk]

For anyone here with a 1995 Deville, I made an interesting discovery the other day. I should start out by saying that it has bothered me for some time now that the 97-99 Deville with the nearly identical digital cluster can show RPM's, coolant temperature and battery voltage readouts in addition to the oil life %, AVG MPG, AVG MPH, Fuel used, and timer. The 1995 SDV however, did not offer the RPM, voltage and coolant temp displays.

Now this is a little thing, but little things irritate me (yeah, it's a personal shortcoming of mine) and I kept thinking that there had to be a way to do this. So, out came the FSM and some heavy reading ensued.

Here's what I found out. Per the manual, the 1995 Seville and Eldorado were available with the digital cluster as well (though I don't believe I have ever seen these cars outfitted with anythng other than analog clusters since the 95 model year) and according to the manual the Seville and Eldo could display these three additional paramters on the DIC.

Ok, so why not the Deville too? Well, it's all in the option programming. I took the risk of trashing my cluster by doing this (and causing who knows what other havoc) but I changed the content of option parameter IS07 to configure the cluster as Seville/Eldorado instead of Deville/Concours.

Now, for the Deville the IS07 option number is normally set at 16, where:

0 = Deville/Concours
16 = Soft Ray Tinted Glass
32 = Seville/Eldorado

* note that there are other parameters in this list, but are not shown here because they are not pertinent to this discussion

The numbers are summed and then keyed in and saved to the cluster. I decided to reset the number to 48, making the cluster think that it was in a Seville/Eldo (32) with Soft Ray tinted glass (+16) just on the hunch that this might cause the 3 missing items to show up on the DIC. The one snag was that I didn't know if this would cause some other problem or malfunction to occur based on other differences in the two car lines.

Well, I finished the re-programming, and exited OBD. I pressed the "INFORMATION" button a few times and what to my wondering eyes did appear, but engine RPMS, coolant temperature, and battery voltage just as I had hoped. Better still, after several days of driving since doing this, there are no codes and no weirdness at all as a result of the change.
<--- me doing my victory dance after finding out it worked!

I should point out that I have not posted the whole procedure here because changing these parameters is potentially risky, entering the wrong values can permanently lock-up the cluster requiring replacement and I don't want to be the cause of someone else damaging their car.

I feel that this type of mod is best left to people who have the factory service manuals themselves as they will more likely be knowledgeable enough to take the steps to do this with less chance of causing problems. Not to insult the intelligence of anyone on the forum (by any means!) I just wanted to make sure no one comes black and blames me for problems with their car based on information I provided.

So, now I have all the information items displayable and the car works fine with no side effects from it's personality "transplant". If anyone else was bothered by this on their 1995 Deville, now you know it can be changed (if you read the big book). Then again, if you were bothered by this as much as I was, you probably need professional help <chuckle>.

Cheers,

Kevin

[smooth3d]

Will this work on a 94 deville?

[Kdirk]

The short answer is: I'm not sure. The 94 Deville had a slightly different cluster in that the transmission gear indicator was still mechancicaly driven by a cable, where the rest of the cluster was digital. Now, this difference shouldn't effect the DIC directly, but I don't know what other design differences there might be in the cluster between the two years.

If you have a factory service manual, check the section on the IPC. It lists the different option override paramters (for the 95 they are IS06, IS07, IS08 and IS09). The 94 may or may not be identical in this respect and there may be different options within each paramter for the different model years.

If the 94 manual reads the same as the 95 for this section, then I would assume it should work, but once again, do this at your own risk. I was lucky that I didn't open up pandora's box by messing with this, it was just my gut feeling - and knowing pretty well how the system is setup - that it would work, and I was right. Remember that this is going against the intended design and anytime we start tweaking these kinds of things upredictable results may occur.

Kevin

[95Concours]

I have a 95 deville northstar also and like you it has bothered me to no end that I cant see the RPM's & Engine Temp, I dont really care to much about the volts though... Where did you get the factory service manuel and how much was it.. Or, if you would be so kind, would you email me the directions, I will take full responsibility for my actions, I'm an adult, I know the risk I am taking. If you dont mind, here is my email gfo106@hotmail.com


Thanks in advance

[Kdirk]

Well,

I'm at least glad to see that I am not the only one who was irked by this. As a friend of mine once told me "Anal-retentive has a hypen you know!".

I can see no reason the N* wouldn't do this too, it is the same cluster AFAIK, just the PCM is different. The PCM sends the data to the IPC where it is interpreted and displayed.

The factory manuals can be bought from Helm, who publishes and distributes GM service manuals amongst others. They are not cheap, about $90 for the two volume set, but very well worth it IMHO, they have saved me that $90 many many times over in helping me do my own repairs.

If you can give me a day or two, I will email you the exact prodcedure from my manual. I don't have it with me right now, so I can't give you the whole thing verbatim.

Kevin

[N0DIH]

I don't have a Deville anymore (well, mine was a 91) but you aren't a sick, you are one of the people who thinks GM should have done it right in the first place. They screw this sort of thing up a lot.

Now, I sure wish I could fix my 94 Fleetwood Brougham LT1 like this!! I would probably have an easier time putting in a Z28 dash....

[Ranger]

Originally Posted by 95Concours

Where did you get the factory service manuel and how much was it.

Helm was running a clearnace sale. They were selling all '95 and older manuals for $30 but I suspect it may be over by now. Check ebay also. I picked up a set for my daughters '99 for $45. I have heard of others getting them even cheaper.

[Kdirk]

N0DIH-

Thanks for the kind remarks. I guess I was a bit too critical of myself for being bothered by this shortcoming.

What I thought was strange is that the Deville did get the full displays in 1997 when they redesigned the interior and cluster somewhat. Apparently, there must have been some squaking about this to cause GM to change it.

What is equally strage IMHO is that this reprogramming of IS07 only changes the information shown on the DIC. In other words, this parameter just adds these three other displays, and doesn't really have anything to do the with the vehicle type outside of the fact the that type of car that the IPC is configured for dictates whether or not they are shown.

Based on the FSM, the data is always transmitted by the PCM to the cluster, and when the IPC is prgrammed as Deville/Concours, it is instructed by the firmware to supress these three items from the display (my own interpretation of what is actually going on here) where they would normally be shown if the cluster were in an Eldo or Seville.

This "theory" of mine is further borne out by the fact that you can get all of this same information by going into diagnostics and bringing up the proper PCM data paramters for display, thus the data is there if the cluster knows what to do with it.

What strike me as odd about this is why GM thought the RPMs, coolant temp and battery voltage weren't important to Deville drivers. I can see the RPM's not being so much of an issue for the "typical" Deville owner, but it would be nice to check the voltage to see if the battery is getting weak, or the coolant temperature to see if the car may be approaching unsafe operating range on a hot day in slow traffic.

Since they saw fit to make this standard on the Seville and Eldorado, it made me feel shorted as a Deville owner, and I guess that's what bothered me more than anything. Now that I fixed their screw-up however, I am quite pleased to have overcome what I think is a senseless limitation imposed by the people who designed the system.

That having been said, I felt that there might be enough interest in this for me to share what I found, and now I see that there is.

Now, if I can just figure out a way to add steering wheel controls to my 95...the madness continues!

Kevin

[ED's85GT]

Kevin, I too have wondered why my '95 Concours wouldn't have a more complete display of vital functions.
Could you also send me those instructions? ( ealtamirano@adelphia.net )
I too will take full responsability for my own actions.

Thanks.

Ed

[Stoneage_Caddy]

cant wait to do this myself as soon as i have time ...have the factory manual and everything ...

tell me what system does the coolant temp end up displayed in ? celcius or farenheight ?

as soon as i do this that stupid voltage gauge can finnaly come out ....

one can never have enough data

[Stoneage_Caddy]

also kdirk as you well know i await your steering wheel radio controll soulution !!

(well i want radio and climate controll )

[caddydaddy]

It does work for the '94 Devilles! I tried it yesterday, it's a pretty cool addition!

Stoneage_Caddy, the temp is in degrees F

[Stoneage_Caddy]

KICKASS !!!

**runs outside with service manual giggleing***

[Stoneage_Caddy]

hahahaha....this is great !!!! 650 rpm ,181F and 13.3 volts @1850 rpm

full instrmentation is good

[caddydaddy]

181F, was it not fully warmed up? Mine was running between 205-213 this morning.