Speedometer/Ac Control lights out. 1979 Ford LTD Landau.

[Mainiak26]

Just installed new alpine head unit into my car.
next night i took it out and my dash lights/heater control lights/ashtray light aren't working.
whenever i try and replace the 4 amp fuse for those three things, it sparks and blows. What do i do? Replace the bulbs? I need to fix this soon because i do a lot of driving at night.
-Alex

[lincolndriver]

hello, seems like if you didnt have that problem before you put thi new head unit, you can assume that one of wires in your new head unit is wired wrong. pull the unit out to expose the wires. check you wiring diaghram. Did you use a wiring adapter or did you just cut and splice? my opinon is that you have the illumination wire from of the dash hooked to a ground source. try disconnecting that wire and turn on your lights. If it doesnt blow the fuse. you found your problem.
hope this helps
dc