Whydoes the signal light come on at random in my 1999 f150 xlt truck

Christophe Thompson

• 1224 Answers
• Posted on Jun 09, 2008

SOURCE: ALTERNATOR AMPERAGE NEEDED FOR REPLACEMENT ALTERNATOR F150 5.4 XLT 1999 VIN L

the basic amperage of all vehicles is 14 now if your using a higher output alternator you will want to go with a 16 or 18 amp alternator but overall you can order the alternator straight from dealer or any parts stores
i dont recommend junk yard for these kind of parts you really dont know what your going to get

J. Gibson

• 1 Answer
• Posted on Sep 26, 2012

SOURCE: 1999 Ford F150 turn signals and running lights aren't working. Changed out 2 blown fuses, but still nothing.

The flasher relay is between the brake and gas pedal near the knee panel. there is a cap over it that you'll have to remove to see the relay. It's part #EP27 from Autozone, also check fuses #13 and #23 in the fuse box in the cab. I just fixed a problem similar to this today.