Electrical Dash Lights Not Working But Light Up With Anti Theft

[Tim83]

I recently bought an 89 GT and the dash lights have stopped working. I have no blown fuses and when the dimmer is turned all the way to the right they still do not turn on. From reading other posts in the forums I would think my dimmer switch is bad and needs checking/replacing. However the car has an alarm and when the anti theft is in effect all the dash lights, switch lights, and cigarette lighter light all flash on and off. I also noticed a 15 amp in-line fuse near the alarm module under the dash was blown but when I replaced it they still don't switch on. My question is, could I still have an issue with the dimmer switch or is there an issue with whatever wiring may have been done when the alarm was installed?

 

[Mustang5L5]

I would ignore what happens when the alarm beeps. You don't really know how it was wired. The alarm itself could feed power to the dash loghts to blink them.

I would troubleshoot this as if you didn't have an alsrm, which means pulling the dimmer switch and testing for power.

I can provide wiring diagram in the am


Sent from my big ass iPhone 6 using Tapatalk

 

[Tim83]

Thank you for the help. I'll start with the dimmer switch.