I just finished trying to fix my tach by changing caps, and I wasn't very successful. I put the old board back in my cluster, and am going to leave it along until I feel like messing with it again.

I figured I should set the shift light to come on so I know I'm at my shift point, so I started looking in Tuner Pro for shift light parameters, and there were none to be found. I did a search, but didn't find any hex addresses so I can modify the ecu file to include them.

I decided to try to find it in the hac myself. Now, I've worked with assembly in school before, but what I've worked with was a "mickey mouse" assembly language. It was very simple, maybe 15 or 16 different opcodes, and that was it. I don't have the hang of the assembly thats in the hac pdf quite yet, I need to figure out what does what.

Anyway, I came across the following which I am certain is what I am looking for. 3 Tables as follows:

; LIGHT ON TABLE
; TBL = % FULL LD * 2.56
;--------------------------------
; % LD RPM
;----------------
L835D: FCB 13 ; 5% 800
FCB 46 ; 18 1600
FCB 118 ; 46 2400
FCB 192 ; 75 3200
FCB 192 ; 75 4000
FCB 255 ; 100 4800
FCB 255 ; 100 5600
;---------------------------------
L8364: FCB 52 ; 1300 RPM, THRESHOLD FOR ENG LIGHT ON
L8365: FCB 204 ; 5100 RPM, THRESHOLD FORCE ENG LIGHT ON

;-----------------------------------
; LIGHT OFF TABLE
; TBL = % FULL LD * 2.56
;-----------------------------------
; % LD RPM
;---------------
L8366: FCB 18 ; 7% 800
FCB 51 ; 20 1600
FCB 123 ; 48 2400
FCB 197 ; 77 3200
FCB 197 ; 77 4000
FCB 255 ; 100 4800
FCB 255 ; 100 5600
;--------------------------------

;--------------------------------
; LIGHT ON DELAY MODIFER
; TABLE
; DELAY vs %TPS
;
; TABLE = (SEC*10)/L836D
;--------------------------------
L836D: FCB 2 ; SCALER
; DELAY TPS
;----------------
L836E: FCB 150 ; 30 0.0 %
FCB 150 ; 30 12.5
FCB 150 ; 30 25.0
FCB 150 ; 30 37.5
FCB 150 ; 30 50.0
;---------------------------------


By the way, I have a functional bulb installed in the cluster for the shift light, and I am running a manual corvette bin as a baseline. The light doesn't come on at any rpm right now.

Just figured I should share this info, and maybe someone has some input on all this.

Now I just got to go figure out how to add this to my ecu file. I'm sure its simple, I've just never done it before.

 

check here for some info -- I made a similar alteration a while back within the 8746 $61

https://www.thirdgen.org/techbb2/sho...ight+params%22

 

Thanks for the link. I had ran across your post in my search. I skimmed through it, but was looking for the hex addresses for my application so I kept searching.

I set up the three tables in my ecu file. That was pretty straightforward.

However, I am having problems getting the shift light to come on while driving. The bulb is fine, since it lights up when I start the car, but it never lights while driving. I am using the AXCN bin (corvette manual) as my baseline. Tranny flag is set to manual. What else should I look into?

I haven' messed with the 3 tables at all yet, they are untouched.

 

Having an automatic, haven't looked at this much.
But I'd try searching for each tables Lxxxx: value in the hac and figure out how the code uses each table.
The link in here tells how tables are used.
Just a little lite reading.....
Table scaling