I have a 1987 Ford Thunderbird V8 5.0
Since I installed a stereo my instrument panel no longer works properly.
When the headlights (and parking lights are off) the digital dash works perfect. But when I turn the headlights/parking lights on then the dash becomes very dim but still is lit up. The dimmer switch doesnt work.
I've tried a replacement cluster and dimmer switch and neither fixed the problem
Everything else works fine (stereo, headlights etc)
All fuses are good
Any ideas?
thanks
Cluster illumination relay, most likely. I used to make mine work in my old Sport by pounding on the dash...
Unhook the ground outta the stereo harness and run it to somewhere on the dash frame. You probably have it running to the illumination wire on the car harness.
something you may not know is that perhaps a couple bulbs have been blown ,,,or,,,, are not making good contact due to the twist lock sockets they install into. Its worth checking out when you get time.
on your issue,, here is a diagram or two you might find useful.