Hazard Flasher and Understanding the fuse panel.
The following stems from an issue we had in our shop. We had power to our brake (stop lamps) and they were working fine. But we didn’t have power on the hazard flasher which prevented the lamps from flashing. So instead of just letting this lesson go to waste, I decided to picture it up and explain the issue.
The power to the tail lamps, the turn signal flasher, the courtesy and clock and the stop lamps is feed to the fuse block by a red wire (A) which connects to a bridge as shown in the picture below. The power from this bridge feeds all three fuses and a jumper wire behind the fuse panel and orange wire (B) feeds power to the hazard flasher from the passenger side of the fuse behind the panel.
If this wire connector is corroded it is possible to have brake lamps but no flashing hazard lamps. The best way to test this is to test for power on the hazard flasher on the driver side terminal (C). The voltage reading at this point should be the same as the voltage reading on both sides of the fuse (D). If the voltage reading is different then you possibly have an issue in the jumper or the flasher terminal C.
In our case, the jumper wire to the flasher was the issue; corrosion at the terminal inside the fuse panel caused the flasher to not pick up the same voltage as the voltage we were reading on the fuse. After removing this terminal from the panel, cleaning it and re-installing it, our issue went good bye. (And yes, you can un-pin this terminal just as you can any other Packard terminal).