FEOA Forums banner

Fuse blowing on running light circuit

1K views 10 replies 5 participants last post by  Intuit 
#1 ·
I have a 97 LX wagon I just picked up Thanksgiving Day that I've only been running it a couple weeks due to some initial issues (lost about 3 gallons of gas in 8 miles after picking it up, topping off tank and driving home due to rubber tube between filler tube and gas tank being in extremely poor condition) and now I'm encountering a blown fuse affecting parking and instrument panel light. I replaced the 15 amp fuse yesterday only to have it almost immediately pop. As it was dark, rigged a couple led head lights (miner style) with red option to the luggage rack in hopes I wouldn't get pulled over on the way home.

Prior to rigging the temporary running lights, I decided to test a 20 amp fuse on the circuit with no intention of leaving it place and when turning on park lights with engine running, heard the engine get heavily drawn down so alternator getting put to work. Tried a few times with same result. 20 amp fuse was not blowing. i walked around car to check lights and all ok. Got back in and considered driving home that way but I could not confirm if something might have been starting to cook so opted to remove fuse and rig alternate markers to get home. Headlight and brake lights and turn signals of course were fine as they're on a different circuit.

I found this thread keep blowing my tail light fuse but wondering if anyone might have something to add specific to a wagon. I've made no modifications to the vehicle wiring-wise since I've had it and up until a couple days ago, the parking light circuit was working fine. We've had some cold weather recently so maybe something flexing has given up. I will try digging into it further when things warm up. Unfortunately no garage here.

Thanks in advance for anything to consider.
 
See less See more
#2 ·
typically in this situation best thing to start with is pulling the housings and disconnecting every bulb in the circuit including plate bulbs. test for blown fuse. usually there is a broken wire in the trunk lid harness between body and lift gate inside the accordion rubber.
 
#3 ·
Thanks Marclar, I'll give that harness inside the accordion rubber a look as I have opened the gate a few times since it got cold. Supposed to be warmer this week so I should be able to dig into it.

Are you aware of any better wiring diagrams than what a Haynes manual provides or at least something that indicates where wires for a specific circuit run on a vehicle? Since I don't have a garage to pull into, I'm up against available daylight and weather conditions so would love to know where to focus during brief windows to troubleshoot. Ideally would love to crawl around entire vehicle and learn it that way. Not afraid to tear into anything but have never had a spot to disassemble and let things sit as needed while researching.
 
#4 ·
My suggestion would be to check the wiring between the hatch and the body of the car. The wires have a habit of fraying and shorting to each other in that section, inside of the rubber accordion looking piece.

I've had to rewire two escort wagons and my current focus wagon for this same problem.
 
  • Like
Reactions: Joey_Twowagons
#5 ·
An easy way to see if this is your problem is to disconnect the hatch wiring - there is a plug behind the panel on the passenger side - then replace the fuse while it's unplugged.
 
#6 ·
Thanks for all the suggestions. I had a moment a couple of days ago to take a look and found the issue at the hatch where the wires flex when hatch is used. Guess it is kind of a bad design based on the number of people that have had shorts there and looks like they carried the design into the Focus as well.

Am posting a picture of what I found though it isn't necessary for those who have had the pleasure of dealing with this already. But maybe someone else will stumble across this.

I didn't have enough time, light, temp and repair bits to permanently fix but as some of the strands in each wire were still intact, decided to wrap all affected wires with electrical tape to remove short then will revisit when I have what I need. I'll avoid using the hatch much until then.

Interesting that you can almost draw a line right across where the casing failed on each wire.

The connection for the rear washer fluid tube seems more along the line of what maybe should have been done for the wires where it just twists slightly as hatch rotates up rather than bending.

Car Hood Light Motor vehicle Vehicle
 

Attachments

#8 ·
I took out my entire hatch harness last year to fix this problem - and still haven't! My wagon no longer has a rear wiper so the only thing I'm losing is the third brake light. Well the rear defroster too but I don't think it's ever worked since I've had the car.

From searching on the Internet, it appears that most makes of cars suffer from this problem, not just Fords.

My preferred way to fix this is to cut each broken wire a bunch shorter and add in a new piece, so the new joints won't be at the stress or flex point.

The proper way to avoid this problem in the first place is to design the connection properly to start - reportedly like they do on aircraft hatches. I can't find the image now, but someone posted some time ago that the wire is wound up several times like a compression spring on either side of the hinge or pivot point. When the hatch is opened, the spirals unwind, and the flexing is distributed over several coils so that there is no sharp bend or kink.
 
#9 ·
To fix mine, I went to the junkyard and cut a section of the same wiring out of another station wagon from inside the car. It hadn't been flexed or succumbed to the elements so the wire was in nice shape and will outlast the car. I shortened the wires in the car and hatch and added the wire I got from the junkyard so it went through the rubber grommet - running them through the grommet is a pain in the butt! At least the wires will match color for color, as long as you get the wires from the right year (97 was different!)
 
#11 · (Edited)
On my motorcycle there are wires that exit the ignition on the steering head and enter the body. As you can imagine, that sees flexing every time the bike is moved; let alone ridden.

What I noticed is, frigid temps and age, make that insulation particularly brittle. So the insulation has fractured.

I've tightly wrapped in spirally-overlapping layers of quality stretchy electrical tape. (I've owned quite a few rolls of junk electrical tape - not realizing it was junk.) Then I used tiny zip-ties space along the length to make sure that the tape doesn't loosen or unravel. So far it has held up perfectly.

When wrapping, you can control/influence the flex points for he wire. The more layers along a section, the less flexing that section does; portion of the stress being transferred up and/or downstream of that section. The wire exiting the ignition has strain-relief and included that in the wrapping. So now nearly all of the flexing occurs downstream near the body.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top