I had a light out in my 88 F-250, so I figured, ok, I'll get a new bulb and put it in. As soon as I put the new bulb in, Wham, both are out now, and there is no power to them. All the fuses are good, and all the grounds I have checked are good, I thought maybe a broken wire, but would that happen the second I put a new bulb in??

 

Do the parking lights work?

 

Gonna have to inspect the headlight switch and connector.

If you never took yer dash apart, pop the headlight and washer ***** usin' a small screwdriver.



Pop off the left side.



Unbolt the headlight switch, and pop off the connector.



Verify power on pin B on the connector (black with orange tracer). If not, you got a busted fuse link by the starter relay.

Jumper with power from pin A, which also has 12v, but fuse protected) to pin H (red with yellow tracer) which goes out to the headlights through the highbeam switch.

If'n the lights work with the jumper, the switch is bad. This can be checked by using a continuity tester from pin B to H on the switch with the switch pulled to on.

Lastly if pin B has power, the jumper to H don't turn 'em on, and the switch checks out fine, suspect the high beam switch. Which has similar testing procedures.

Adrianspeeder

 

Ok, now, my flashers work, my turn signals work, my brake lights work, my interior dome light works. But, none of my head lights, dash lights, or tail lights work. It seems like my switch took a dive on me.

 

I would say your fuse link is open at the starter solenoid.

Does your horn or cigarette lighter work?

 

actually no, my horn doesn't work, I'm not sure about the cig lighter, but I though the horn was a different matter, no power to it either. If its no trouble, could someone tell me how to locate and check the fuse at the starter solenoid?? BTW, you guys are great, I never had this much response when I needed help in the Chevy (yes I used to drive and fix Chevs, but I really love my Ford) forums.

 

The horn, cigarette lighter and power to the Headlight switch all come from a single fuse link.
Of course it would be on the battery side of the starter solenoid where the big cable bolts on to the big post. Where the small wires leave here there may be a square rubber thing on the wire or not. At any rate pull on fuse link with both hands and if it stretches it is bad.

It is on the BK/O #38 wire Fuse Link "L"
http://i54.photobucket.com/albums/g9...ging/PG015.jpg

 

You gotta get around to pullin the switch like I outlined to verify the origional problem.

x2 on agreeing you blew the fuse link for everything that no longer works. I gotta get around to takin' a better picture, but you can see one off to the right in this picture on the green wire (happens to be for the alternator charge line)



You'll be lookin' fer the black with orange tracer wire.

Adrianspeeder

 

Wow you're quite the electrcian. I don't know much about that stuff. Might I ask why you have those relays at the top and your own custom fusebox?

-Chris

 

What does the photo have to do with the fuse link he blew?
Why do you think he still needs to pull the Switch?

 

Seriously bro. these pics are incredibly helpful!!

 

Pictorial example of a fuse link

Heh heh, thanky. I'ma third year electrical engineerin' major specializing in power transmission. Known by my civil and mechanical engineerin' friends as "the jolt jockey".

Anyway, have a slight obsession with using relays for high current draw applications for my electrical upgrades on all the trucks. Simply easier to group them all together with a new fuse panel to keep stuff neat.

From left to rigth on the '88s setup pictured above...

Relay for 110watts of aux reverse lighting to make backing up at night super easy as well as hitching up trailers in the dark.

Relay for the low beam to seed full voltage directly to the headlights through 20amp wiring so super bright instead of a longer path through the headlight switch and undersized wiring. This is a worthwhile mod to do actually once we figure out yer problem.

A relay to run the blower motor and AC clutch. Long story on that one.

Relay for the high beam circuit to also send full battery voltage directly to the headlights through 20amp wiring so super bright. Also this relay is controled by a toggle on the dash (to scrap the goofy floor switch) and comes on along with the low beams for super beams. Again, a handy mod.

Lastly a relay for the air horns.

Get to checkin Ken, and we'll get ya fixed up.

Adrianspeeder

 

I do not know how the photos are helping you but did you look at the diagram in the link that I posted for you above.

 

My highbeam switch is seized as well . I'll get on this and post my findings tomorrow, I am very very interested in having a highbeam toggle on my dash as well, once I get all this other stuff figured out of course!

 

Ok, I just took a pic of the actual fuse link in question to be a bit more helpful than the first pic posted. This goes along with yer diagram good.



It's the only one with the black/orange wire after the link.

Adrianspeeder

Interesting, that could very well be the origional fault if it shorted somehow.

Adrianspeeder