Cluster lighting issue and other problems can be caused by tarnished contacts and broken contact points on plugs. I am going to show what i did. I can't find the plugs in the junk yard anymore.
A lot of people will pull the cluster and wire in new gauges manually, rather than trying to fix the original setup. Unfortunately, I have not found a manufacturer who makes pigtails for 1979 - 1986 gauge cluster yet.
Challenges that early Foxbody owners still face. It's sad really, you can order everything for the 1960's generations cars but you can't order everything for the 79 into the mid 80's...
Now the gauge cluster blades here sometimes get broken and then don't make good contact to the cluster power ribbon on back of the cluster.
A lot of people will pull the cluster and wire in new gauges manually, rather than trying to fix the original setup. Unfortunately, I have not found a manufacturer who makes pigtails for 1979 - 1986 gauge cluster yet.
Challenges that early Foxbody owners still face. It's sad really, you can order everything for the 1960's generations cars but you can't order everything for the 79 into the mid 80's...
Now the gauge cluster blades here sometimes get broken and then don't make good contact to the cluster power ribbon on back of the cluster.
My dad actually showed me this trick using an aluminum can to make a contact point with some tin snips.
Make the contact point fold it a few times to make it a little thicker and bend it to fit into slot ontop of the broken contact blade. You should have good contact again.
Another issue is with the power ribon over time and the light sockets get tarnished. I used some Wizards Shine Master polish and sealeant to clean up the contact points. A little carefull rubbing and you'll go from dull to shiny in no time.
Wire harness plugs in here and could use a cleaning as well.
source: Fox Body Mustang Restoration http://bit.ly/2rzxYS9