92 f150 radio back-lighting issue
 

I just purchased a new OEM 2003 radio with cd player for my 92 f150. The add said the back light may not work for my year which as it turns out is true. The back light works when the radio is turned on but then goes out when the lights are turned on. Everything else works great but ONLY when I turn on the headlights the back light goes out, anyone know how to correct this issue? Thanks for any input.

The ad stated, "**Late 80's and early 90's vehicles often had a different illumination circuit, so the button and display back-lighting may not work in those vehicles as delivered. The numbers will still show on the display though. It is just the back-lighting which makes the numbers easier to see at night that is sometimes an issue. It is possible you can change the illumination wires in the harness and make the back-lighting work with older vehicles but instructions for this are not included."

Eh, kinda shooting in the dark here, but some after-market radios had a lead from the instrument panel lighting circuit to tell the radio light to be on, whether the radio was powered up or not - to synchronize with the rest of the instrument panel lights - an appearance thing.
Given that the operation seems to be backwards, suggest to find the pin-out of the wiring connectors and just pull/disable this sensor wire lead to the radio, if present.

Thanks Cape,
Not sure if I would call this an after market radio since it is a new OEM Ford radio just from a newer year than my 92 but I will certainly try what you have suggested. You never know it may just work. Thanks for your input I appreciate any help on this problem.

I find it interesting that it lights up fine when I turn the key on but then goes out when I turn the lights on.