Thanks for the advice, Bugg. I did a thorough check for loose wires and dirty contacts, and everything seems to be fine. I didn't find the black box under the dash where the other relays are, though. I searched the threads and found where it is on some earlier models, but did they maybe change it up in 04? I can't find a 3x4 black box anywhere under there.

Here's where I saw the black box on other trucks, but it's not there on mine:


And this is underneath my steering column, I already replaced the blue flasher with an EP27, and no change:

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2004 Black Ranger Edge Supercab
4.0L SOHC, 5 Spd Manual
Flowmaster 40 Series Single In Dual Out
31X10.50R15 Federal Couragia A/Ts
Bedlined: Mustang Dome, Explorer OHC w/ Buggman LED Panel , Radio Bezel