1989 f150 5.8 has absolutely no tail or brake lights. Blinkers work, but tail lights don't. Can someone send me a schematic? Also, has anyone thoughts on this? Apparently the fuses are good, but as this is my roommates truck, I don't really know where to start.

 

I dont have diagrams for this, but see if the emergency flashers work. If they do try the brake lights again. Sometimes this will clean up dirty contacta in the MFS/multifunction switch.
Sign up for a free account at bbbind.com and you can pull up the diagrams

 

So the signals do work, but the hazards and brake lights do not... They are new bulbs, so I'm somewhat confounded.

 

Just took a quick look online and stop and hazards are on the same fuse. Fuse 1 and it's a 15 amp
If the cruise control cuts off when you tap the brake the fuse is OK.

The online diagrams dont show it, but i think the hazards and brake lights are wired to the hazard flasher.

 

If the turn signals work, but the Hazards don't, I'd suspect an issue with the hazard system or the turn signal switch itself.

 

I just went out and rechecked her fuses, fuse one is fine. As for the switch, I changed the brake switch itself so it has to be deeper than the switches. As for the cruise, I'd wager it hasn't been connected in twenty years. Tomorrow I'm going to start with the hazard flasher and go out with my multimeter and just start chasing the wiring from the light assembly to the engine and drill blindly hoping to strike oil. I'll definitely be sure toilet you guys know what I find out. Thanks for all the help.

 

Yeah, could be as simple as a bad hazard flasher. Have fun.

 

Do the dash lights work? If not, it could be fuse 4 or fuse 17. I went in circles for a long time because I thought I was checking the right fuse, but I wasn't. It never hurts to go through the entire fuse panel occasionally and make sure everything is in order. I wasted a lot of time under the truck looking for shorts before checking all my fuses.

 

Yea, I'm going off of what she told me. I plan to start with the fuses and go from there. Does anyone have a fuse diagram for this old girl?

 

Fuse assignments are in the owner's manual. As for a diagram, there isn't just one. It's a whole book, the EVTM - Electrical and Vacuum Troubleshooting Manual. Usually available for most model years used on eBay, and worth it's weight in... well... very expensive steak, perhaps.

As for the taillights, also check the front parking lights, and the dash lights as mentioned. Park/tail lights are on a separate circuit from stop/turn/hazard lights, so you may have more than one issue.

 

So there is not power at the fuse. What exactly does that mean?

 

Check all the fuses both under dash and underhood. Fuses can often power other fuses.

 

Which fuse does not have power?

 

I learned that the hard way. Fuse 17 was powered by fuse 4 in my case. I tore the dash half apart before I realized that.

 

Pretty-much every fuse in the interior fuse panel is energized by a fuse in the underhood fuse panel. Yet another testament to the value of the EVTM.