1994 Ford F-150 CHASIS RUST AND BLOWN FUSES

BOXTY_MAN

MEMBER
1994 FORD F-150
V8
4WD
AUTOMATIC
109,000 MILES

My Ford began experiencing electrical problems about 2 weeks ago. First the fuse for the stop llights/parking safety switch. When starting the car I now have to turn the ignition key to ACC, move the shift to neutral and then start the car.

A couple of days later my directional signals went out although they began working again 2 days later. The only fuse that has blown is for the stop lights/parking safety switch. I've replaced it and it just blows out again as soon as I step on the brake. I did replace the stop lamp brake switch but the problem is still there.

Lastly, I noticed the chasis is very rusted, not surface rust, the engine oil pan has rust that is scaling and I will be replacing the pan. Would a short circuit cause the chasis to rust.

The truch is in otherwise very good condition with only one surface rust spot just below and behind the driver's side door.

I would appreciate any help you can provide. Thank you in advance.

Brian

5 Replies

BUDDYCRAIGG

MECHANIC
2,262 POSTS

Hi.
I'm going to cut your question up in to each question.

That is your neutral safey switch.
It keeps you from being able to engage the starter if you are in any gear other than Park or neutral.
It's either out of adjustment, or most likely, the contacts are worn out in the Park position.

Not really, yes, electricity has something to do with rusting. But a short would not cause your truck to rust out.

I want you to try something.
Turn your hazard lights on.
If the fuse blows, let me know and will do some more digging.
If the fuse does not blow, then the problem has to be with the green wire that runs from the brake light switch to the high mounted brake light (check to make sure it's not full of water too)
or the electric brake controller (if it has one)

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Monday, July 20th, 2009 AT 8:27 PM

BOXTY_MAN

MEMBER
3 POSTS

Hi Buddy,

Thanks for quick reply.

Electrical first. Yes, the hazard lights do work if I put in a new fuse. When you mention the Green Wire running to the high mounted brake light, I presume you mean the light mounted near the roofline on the back of the cab. I think you're on to something here.

I did tinker with this because 1 of the 2 backup lights was not working. I couldn't get the assembly out completely (and believe me I tried everything but didn't want to break it, even removed the interior headliner) but I was able to get a couple of fingers in behind the connections and something must have moved and the light was working. It has since failed again. I wasn't able to see any corrosion or signs of water. It's pouring rain here now (NJ) but if the weather breaks for a little while I'll give it another shot. Any suggestions on how to get the assembly out would be appreciated.

Chasis Rust. Could this be caused by a bad ground? If so any suggestions? Also, I will have to do something about the rust. Should I clean and paint over with rustoleum? Again, any suggestion would be appreciated.

Lastlly, I don't think the Neutral safety switch has a mechanical problem. From what I have read, you have to step on the brake to move the shift out of park. When I step on the brake the fuse blows and therefore the Safety switch is not getting the signal that all is clear and won't let me put the car into gear.
Does this sound right? Any additional thoughts?

Once again I want to thank you in advance for all your help. I really appreciate this.

Brian

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Tuesday, July 21st, 2009 AT 10:40 AM

BUDDYCRAIGG