Because the turn signals are a completely separate curcuit from the emergency 4 way lights. The turn signal wiring has a short that causes the fuse to blow out. In order to find that short, you need a technician that specialises in electrical wiring repairs, because you could spend days trying to find it and fail. It will cost some money but less than the value of the truck, or a traffic ticket for "no signals."
You may want to check the brake lights.Everything runs through the multi-function switch.(the turn signal switch)
The signal and 4-way flashers are behind the lower dash panel, aprox under the radio. The lower dash panel must be removed to gain access to the flashers.
If your referring to the emergency flashers.... it'snactually in the turn signal switch. i have a 94 mercury cougar xr7 and when i bought it the emergency flashers did not work. i in the end i had to replace the entire turn signal switch in the steering column.
Both the emergency and signal flashers are behind the plastic lower dash panel aprox under the radio. The panel must be removed to gain access.
The turn signals on a 91 caprice do not work, the emergency flashers do.
There are two relays, one for the emergency flashers, and one for the turn signals. Your turn signal flasher is defective and needs replacing.
Go to Autozone.com and you can find out what flasher, and where it is located. :)
The turn signal and emergency light relay flashers are located behind the plastic lower dash panel, aprox under the radio. The lower panel must be removed to gain access.
The Fiero has two flashers from the factory, the signal light flasher and the emergency or four way flasher. These are identical GM style two prong flashers. There are many quality levels and even a few novelty flashers available.
There are two flasher relays side by side. One is for the signal lights, the other is for the emergency flashers. They are the same relay so you can swap the two and see if the problem your having changes when you try to operate them.
Not sure what vehicle you have but with most vehicles the signals and emergency flashers are separate circuits. Each have there own fuse and flasher. Check fuses, bulbs and flashers. If all checks okay it may be the signal switch at fault.
Some cars have two flashers, one for the signals and the other for the emergency flashers. Be sure you replaced the right one. Also check the fuse the bulbs and lastly the signal switch.