zumi

Hi, I have a problem with electric circuit on my 1997 Ford Escort wagon. Few weeks ago the rear door control light came on, which meant that the Room fuse died. I changed it and also realised, that the insulation on some of the wires in the rear door was cut and wires were touching probably causing short curcuit and killing the fuse. I managed to separate them with a black tape. For a while the car was ok, but after few days, my break lights turned on even though my car was parked and not used. I checked the wires almost all the way, they seems to be OK. When I removed the room fuse (15A), the break lights went off (they work as usual while driving though), but the radio is not working anymore, as well as the trunk light. But everytime I break while driving, the radio gets power and comes in (room fuse is still out). It sounds like real mess, can somebody help? Many thanks. O

SABL

Was the insulation cut or was it burned? Big difference on that issue. If it was cut, how did it get cut...something sharp in the area? Did the wire get "pinched" by something? Are rodents (mice) chewing on the wires?

If the wires are burned that could mean a bigger problem. Make sure the fuse is the right "size" in amps. NEVER use a larger capacity fuse, if the fuse "blows" you have a problem that needs to be addressed. A larger fuse is never the solution.... only correcting the problem is the right answer. Look at the fuse box cover, it should tell you the proper size fuse for that location (circuit).

Something is causing a "backfeed" in your wiring....could be a bad ground wire or could be crossed wires from lack of insulation. Recheck the wires you fixed earlier to make sure the tape is still seperating the conductors.

I will check the schematic to maybe get a clue as to what is happening in your situation, but in the meantime go ahead and look for broken or burned insulation in your wiring.

SABL

zumi

Hi and Thank you for help. I have rechecked the wiring, I even took of the inside plastic covers to see as much of the cables as possible. No more cuts of insulation were visible. I also rechecked my previous taping, it all looks good. Cables are completely separated and the cuts covered. The cuts seem to be like from a knife or sharp object, but definetly not from burning or heat (have not seen any heat/burning related damage anywhere). The cables look healthy, apart from those cuts. They are in the area where the rear door is attached to the back of the car (wagon) - the cables exit the door and enter the rear part of the car. The insulation might got cut by repeated opening and closing of the rear door, although they run in a rubber envelope which looks untouched.
I also checked all the fuses. They are OK and of proper size. It is a big puzzle. Thanks a lot for help.

SABL

I guess the next thing to do is to see why the brake lights fail to turn off. With the fuse removed you might be "backfeeding" the circuit. The brake light switch should be under the dash and mounted behind (towards the rear of the car, closest to you when looking at it) the lever that the brake pedal is attached to. If you have access to a continuity tester, remove the wiring connector to the switch (with the fuse removed) and check for check for a continuity between the two switch "posts" (where the wires connect). You should get no reading with the pedal in the "up" position, if you do get a reading check the switch to make sure the "plunger" operates freely. You may have a bad brake switch and will have to replace it.
The fuse you removed should have been at location 28 and is 15amp as you stated. I will continue with my research in case your problem is not with the switch. Please post back and let the forum know how you are progressing.

zumi

Thanks. Unfortunately, I do not have a continuity tester, so I could not test the switch this way (I am trying to get one). I tried the following though: I have disconnected the brake switch under the dash (as you adviced) and then put back the fuse into its slot. Even at this configuration, the brake lights switched on (the engine was off and no key in the starter). The plunger seems to work freely.
I have to correct myself though. In my initial message I stated fuse of 15A. However, the problem I had from the beginning was with the fuse in the so called Room slot, but this fuse is 10A. I have to add, that everytime I am putting back this fuse into its slot, touching the connections produces noisy sparks. It seems that this circuit is highly alive. At the moment, I am driving the car with the fuse out (otherwise the brake lights would be on even if I stop the car), so no room lights, no car radio works (although as I said before, the car radio and the clock switches on everytime I press the brake).

SABL

I haven't given up yet....just a little slow in responding due to my workload.

I need to know the location of the fuse (the number of the circuit) that is sparking when you attempt to put the fuse back in. That will help me in tracing the path that the wires.

I will check back this evening or tomorrow at the latest.

SABL

zumi

Hi. Thanks a lot for help. The number of the circuit is 13 (or called Room, 10Amps) and it covers clock, interior lamp, luggage compartment lamp, safety belt warning chime, radio power). I hope this helps.

SABL

My schematic shows #13 to be 5 amps and controls the relay for the blower motor, the airbag and the electronic temperature control. This is also the information I get from the manual that comes with the vehicle.

I'll trace the route of the circuit that supplies power to your radio and other accessories that you have mentioned and see what I can find.

SABL

If you attempt to reinsert the "room" fuse, which in my understanding supplies the interior lighting system, you WILL get some sparks due to the "load" that is in demand because ( I assume) you have the car door open. This will be normal....but if the load excedes the 10amp rating and causes the fuse to "blow" then you have a problem. We still need to find the reason why your brake lights remain on. If you disconnect the brake switch and the brake lights still remain lighted or lit then you have a problem further downstream.....something is providing a power source to your brake lights. Backfeed is unlikely if the brake switch is disconnected.....a circuit must be completed or "closed" for any power to flow.

I did look at my Taurus ...1999.....and did notice that I have two switches connected to the brake pedal....perhaps you disconnected or tested the wrong switch? I will look into this "situation" and see what I can find.

mack1

Hi Zumi,

I think you have a short between the brake light circuit and the rear compartment (room). To be more specific, I think the hot wire going from your break light switch
is shorted to the hot wire to your rear compartment. That said, you can forget about any wiring at the front of the vehicle. It's likely at the place where you did the repairs at the rear door.
I think SABL hit on it in his first post.
To find the short, start at the brake light switch under the brake peddle or at one of the tail lights. Notice the wire colors, they probably don't change from switch to tail light. Try to follow the wire from there toward the rear compartment. It probably enters into the same wire harness with the room compartment bundle. Try to follow that bundle looking for places where they can be damaged and shorted together (again, most likely place is at that door where you did the work) You should take that work apart and take another look. Here are a few pointers on fixing that mess.

When wires are broken or cut, use butt splices and crimp tool to reconnect them. A butt splice is a short straight tube with insolation on the outside and a small metal tube inside. Strip a short section of the broken wire and slip it into the butt splice and crimp it. Strip the other end of the broken wire and slip it into the other end of the butt splice and crimp it. Pull the connection to make sure both crimps are good. You can get but splices at Walmart or any auto parts store. I saw some today when I was getting my oil changed. (I quit doing my own oil when I found out it was about the same price to get it done)

On using black tape (which unravels when it gets hot), tape bare wires with overlapping winds of the tape, being sure to cover the start point such that it can't come loose. At the end of the tapeing area, leave about 6 to 8 inches of tape past the wrap. Press the sticky sides of this extension together leaving the length such that the unsticky part of the tape is on both sides of the results. (an unsticky extension that can be tied like a thread, or cord) Put two half hitches on the end of the taping. (a wrap around the work with the end slipped through the loop and pull tight. Do this twice). At the end of the last half hitch, tie a knot into the remaining part as near as possible to the last half hitch and cut any excess off. This will give you a taped area that will not come loose when it heats up. You'd be surprised how many folks don't know this trick, but now you do.......or maybe you already knew.

The short is between hot wires, which makes it a much easier problem to find. Ground problems are normally the hard ones to find.

Hope this helps.
Best regards,
Mack1

zumi

Hi there. Thank you all for your help. I will try to re-check everything and will try to trace the wires as described above. Sorry for late reply. I was away up north. In case I find the problem, I will let the forum know. rgds.

mack1

Hi Zumi,

If you can't find the short, post the electric prints and mabe some of us can help and be more specific.

Wishing you the best,
Mack1