i have a 1986 trans am i installed a after market digital dash for all the gauges

i noticed while driving at night my temp reading on my digtial aftermarket dash is like 20-30degrees higher than normal

i realized that the temp reads higher with my headlights on and instantly drops with the headlight switch off and rises instantly with headlight switch on

i would play with the switch on and off and watch the temp just drop or climb with whatever position the switch was in

the wiring is exactly the same that was used with the original dial/meter gauges

using the same wires i did nothing custom.

what could be causing this?

 

Sounds to me like it could be a wiring problem with your digital dash. Install the original cluster for a test and see if it has the same problem.

 

well it just seems totally weird

maybe the temp wire to the gauge is shorted or connected to where those in dash light bulbs used to be so your dash lights up when your driving at night and have headlights up?

the manual had me remove the bolts but maybe somehow makign contct with the copper paper circuit board on the back?

 

The temp gauge by readint resistance to ground. Somehow the resistance to ground of the sender wire changes when the lights are on..