Open Road

i have a couple of digi dash's one from an 89 and one from a 90
part number stickers on them are 92864115700 and 15701

is there anyway to power them up to get a mileage to display?
i have the 4 electrical connectors that plug into them

have tried on plug 2
pins 12 &13 12v
pins 14 & 15 to ground
pins 16 & 17 12v

that gets the back lights to light up, but it just fully illuminates the 3 LCD displays and puts the oil pressure gauge to max.
as pictured
cheers
Phil

Pretty sure you'll also need 15 bus (ignition ) power to get the mileage display.

You may also need the stalk assembly connected...

I don't know for sure having never attempted this.

thanks Dave, if i get it to work i will post back on here.
cheers
Phil

Mark Anderson might have some insight into this. there is also a digital dash service manual out there

maddog2020 wrote: ↑Sat Mar 28, 2026 11:47 pm Mark Anderson might have some insight into this. there is also a digital dash service manual out there

Indeed, there is:

jschiller wrote: ↑Tue Mar 31, 2026 5:18 pm

maddog2020 wrote: ↑Sat Mar 28, 2026 11:47 pm Mark Anderson might have some insight into this. there is also a digital dash service manual out there

Indeed, there is:
928 S4 '89 - Diag of the Instument Cluster.pdf

top man
cheers
Phil

finally had to get round to proving the mileage of a digi dash, as i had a buyer for one.
many thanks to Smiffy for coming up with the how to below:

Plug 2 pins 16, 17 battery + red with a black stripe
Plug 2 pins 14, 15 ground - brown
Plug 2 pins 12, 13 ignition + black with a red stripe

with 16 + 17 +12 +13 to + battery and 14 + 15 ground, the 3 LCD displays come on in orange fully lit, THEN after 5 seconds they turn red and display CAL picture of a gas pump RANGE.

THEN remove 12 + 13 from the battery and the LCD reverts to orange and displays the mileage for a few seconds just as when turning the ignition off in the car.

and can confirm, but probably widely known, that the mileage is stored in the back PCB pictured below, as i swopped it into another front section and it transferred over

and bloody typical the other one that i actually needed to know the mileage on has a failed PCB, pictured

hopefully will help someone in the future
cheers
Phil