digital speedo in 1990 fastback,will it work?

[mantis-S13]

i have a gauge cluster out of a 1989 240sx coupe and i wanted to replace the one out of my fastback with it. i used the harness off of the coupe so everything would plug up but only the brake lights,gas hand and temp gauge work. i have a dohc swap as well and i know the stock 89 tach wont work with the engine. i just was wondering if the digital speedo would work. and yes i have searched and all i could find is stuff on fixxing HUD.thanks

[180fan]

don't see why not. just remember you'll be in for some minor wiring during this process.

[mantis-S13]

well i put it in using the digital speedo harness and now it doesnt work until about 30 minutes of driving. but when it does i love the new look.what is the wiring problem?