I've got a '98 E350 Club Wagon. The brake light fuse used to blow about once every three months or so, but now blows every time I drive it. The ABS light is also on but I don't have a way to read ABS codes, nor do I know if it is related to the fuse issue. So far I have:

Checked tail/brake light sockets for corrosion/burnt spots.
Checked wiring where visible.
Replaced bulbs.
Replaced brake light switch.
Replaced turn signal/hazard switch.

The van is a high top. The top has no third brake light but I'm pretty sure the van came stock with a third brake light. I'm wondering if maybe the unhooked wire to the third brake light has rubbed on something up in the top. I haven't found an easy way to access it yet. Anyone have any other ideas on what may be causing this or better diagnostic procedures I could try? Thanks

 

Nothing? Can anyone recommend another forum?

 

I think your third brake like suspicion is a good one to follow up. I have no idea how to get up in there, though! You might try to find where the wires get up there. I suspect it goes up from the regular brake light up inside the "pillar" at the rear, where the doors mount. If you can find wires that go up there, you could cut them and tape them off to see if that cures your problem.

 

Double post.

 

Or, it might be Ford's infamous speed (cruise) control kerfuffle.

There is a normally-closed diaphragm switch screwed into the nose of the brake master cylinder and the 2 wires connected to it are ALWAYS live, as long as there is a charged battery hooked up. Whenever you step on the brake pedal, the switch breaks the connection; when the pedal is released, the circuit is re-energized. Eventually, after several thousand brake applications, the diaphragm in the switch cracks. Now, when you step on the brakes, you squirt electrically conductive flammable fluid directly into the normally live electric portion of the switch. There are 2 possible outcomes: if you are lucky, the circuit shorts through the fluid to the MC and blows the fuse, which also protects the brake lights, the turn and hazard flashers, and the shift interlock. If you are not-so-lucky, the switch does not short, instead vaporizing and igniting the fluid, then the switch, its wiring, then everything else flammable in the engine compartment, and, usually, the rest of the vehicle, as well.
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There is a recall from Ford on this, but the fix is easy. Replace the $20-ish switch and install a 2 amp in-line fuse in one of the 2 switch wires.

 

I *think* I found the fuse problem. The third brake light wires appear to run up the driver side rear pillar, so I started pulling interior panels to follow the wires. When I got to the side panel of the high top, there it was. In the pic, you can see the bare wire in the V of the harness. I assume it's the hot for the third brake light...I didn't have anyone around to press the pedal to confirm with a meter, but I taped it up and haven't blown a fuse since. Time will tell. Thanks for the comments and info.

 

Yep. That would do it. Glad you found that.

And thanks to rustbucket for the info about the brake issue. Good to know for future reference.

 

That brake cylinder info. makes me glad that I did a DIY cruise control and did it on the CHEAP.
By which I mean I did NOT install a new Master cylinder with the CC safety pressure release switch in it.
I just found the plug end of the wires that (would have connected to the MC) if my vehicle was a factory CC unit.
I Cut the plug off, stripped some insulation off the ends of the wires & just wire wrapped the 2 wires together. This allowed the cruise control to work with my wrecking yard CC steering wheel I bought for $50.
Not the $1700 to $2000 the filthy rotten dealership told me it would cost to convert (IF IT COULD BE DONE AT ALL!!).
Anyone wonder why everyone calls them STEALERSHIPS & hate them with so much passion?
Flood Ford in Rhode Island is a good place to go. (If you are looking for incompetence & thief's).
Just thought everyone should know to avoid that place like the plague. DDT