#5 fuse

[Fordbullittboy]

The long questioned but rarely answered question. I still have some searching too do but i'm trying to track the short problem on the number 5 fuse. Its a 93 Manual. It blows the 15 amp fuse almost instantly, and then other times its speratic. I've disconnected the following and still no luck: Fog light relay, Brake switch, Headlight dimmer and autolamp. I have a feeling it may be the eatc itself???? I'm gonna continue to disconnect things to see if i can find the circuit it is on. Any help is appreciated. I need to disconnect the reverse switch and also check the wiring on the O2 sensors. Please any comments are greatly appreciated, this seems to be a common problem and not many answers according to my searching. Thanks- Tom

 

[FREAK_SHO]

Some have had problems with the head lamp switch shorting or one of the O2 sensors shorting, as the O2's are on that same circuit as well.

 

[projectSHO89]

Tom,

Here's the relevant schematics for fuse # 5:

1993 Taurus Fuse #5 pg 1.pdf
1993 Taurus Fuse #5 pg 2.pdf

As you can see, this circuit feeds numerous items and sub-assemblies.

On pg 13-13, eliminate the cluster, the shift lock actuator, and the Sable components. On page 13-14, eliminate the "EXCEPT SHO" and the MLPS portions.

That leaves the MFS (flasher), keyless entry, illuminated entry, rear defrost control, EATC, airbag module, DRL (if equipped), PNP switch, HEGOs, and VAPS module.

Do try disconnecting the HEGOs. Of the list of possible suspect components, they'd be at the top of my list. Look for any evidence that the wires are leaning against the exhaust system or the rear sensor wiring is rubbing on the intermediate drive shaft. There is also the possibility that one has shorted iinternally. Disconnect them and drive it to see if the fuse blows.

Steve

 

[Fordbullittboy]

Thanks Steve and Dave
i'll try those, its prolly gonna throw a code starting the car without the O2's connected right?? is that bad for the car to run it without the O2's connected? Will it run too lean or rich?? Thanks again guys.

 

[projectSHO89]

Yes, it will set a code or 2. I'd limit the operation as much as possible.

Steve

 

[Fordbullittboy]

Would the fasten seatbelt light be on the same circuit too? It is on all the time now? Just noticed that is something that has started recently.

 

[projectSHO89]

Would the fasten seatbelt light be on the same circuit too? It is on all the time now? Just noticed that is something that has started recently.

Nope. Different circuit.

 

[Fordbullittboy]

New Question Widdling It Down

Okay, i was able to get under the car and move and look at some wires. Although i didn't disconnect a O2 sensor I was able to find out that the fuse blows as soon as I touch the brake pedal. I haven't checked to see if it also has to be in reverse. Yes it was in reverse when i diagnosing this. So i unplugged the two switches on the brake pedal. I'm assuming one is a brake light switch and the other? ABS Something?? even with both of these connected as soon as i touch the brake pedal it blows a fuse. I blew about 4 fuses trying to see if disconnecting them would help. So I have new questions, Where from here do I go from here??? Please any suggestions!??

 

[projectSHO89]

even with both of these connected as soon as i touch the brake pedal it blows a fuse.

Is this correct or did you mean to say "disconnected"?

If both connectors were disconnected but the fuse blew when the brake pedal was pressed, it would almost have to be a part of the brake pedal arm rubbing against a wiring harness or bundle... Can't think of anything else plus my 94 is away from the house today so I can't look at it.

Steve

 

[Fordbullittboy]

yes I meant to say disconnected. It was dark and I didn't see any wires getting rubbed pushed or pulled. I'm gonna hopefully check today to see if i can see anything. I'll keep everyone updated. What is the white plug that goes to some kind of switch?? I know the other is the brake light switch.



- Thanks steve