THe fust for my turn signals and back up lights keep blowing...im trying to trace the short with no luck...THe fust still blows with the flasher being pulled and checking the wire diagram that leaves the back up light side. COuld the back up light switch be the culprit and if so where is it located on tranny?

I dont know what tranny i have, the door jam states transmission D.
its an 89Bronco II manual 2.9 4x4.

ANy ideas?

 

Trans code "D" is FM-145/146 (Mitsubishi), and yours is more than likely an FM-146, because of the model year of your BII.

What you probably need to do is remove all of the bulbs, and the fuse, and check all of the wiring for those circuits for grounds and isolate them. I thought "we" had fixed this problem with you before??

 

I also thought we had fixed this problem, but hadtn driven the B2 in a yr or so and its back.

question- IF i pull flasher for turn signals from the fuse box and the fuse still blows does it mean that the short is on the back up light side? Referring to a Chilton manual it shows power from that fuse going to turn flaher and back up switch. SO if i pull flasher power never goes to turn signal bulbs or anything past the flasher on that circuit..which leaves the back up signal. THis sounds logical?

 

If it is ONLY fuse #5 (backup/turn signal) that blows, and you pull the flasher and it still blows, then that would be a safe assumption that it is on the back-up lamp side of the circuit. I would pull the fuse, backup lamp switch connector, all your bulbs and flasher, and then trace the wiring from there. IF, with all of that disconnected, you read continuity from ground to the output side of your fuse at the fuse block, then it's somewhere BEFORE the backup lamp switch and flasher. IF you read continuity to ground on the output side of the backup lamp switch connector, then it's between the switch and the sockets. If you read continuity to ground on the output of the flasher, then its between there and the sockets, but if not, then this would verify it's not the turn signal part of the circuit. You may also have to disconnect the multi-function switch connector in the steering column, and check both sides of it as well as the switch itself, and also check the back-up lamp switch (clean it up, and check, etc.). I hope this gives you a more logical approach to fixing the situation (again). Could be as simple as the taillight assemblies being all hosed up, could be as complicated as having nicked /pinched wiring in the harness underneath the truck, which both are possible. I think my '87 may have had this problem at one time or another, considering all of the taped-up wiring in the harness underneath the truck... but luckily, *I* haven't had a recurrence yet (crossing fingers, hoping not to jinx myself! lol). Again, hope this helps in troubleshooting the problem. Let us know if you get it fixed and where it was!

 

Sounds good, where is teh backup switch located? IS this the same switch as the neutral/start switch on side of Tranny?

 

Automatic trannys have the neutral safety switch, Manuals have the switch on the clutch pedal, as far as I know. There should only be at most two wiring connections on your 5-speed: One for the speed sensor, one for the back-up light switch. The back-up light switch should only have two wires, purple w/orange stripe and black w/pink stripe, and it should be located somewhere in the middle of the transmission length-wise, on the side. The speed sensor is usually located on the tail of the t-case, if I remember right. Hope this helps

EDIT: I guess the there is also a neutral sense switch on the transmission. Wires are White w/Black stripe and Black w/White stripe. That should help identify which is which. Not sure if they are on the same side or opposite sides. I guess I should go try and start my truck in neutral....

 

Grab an old headlight (good element) and jump it across the fuse holder.

Anotherwords use the lamp filament as a fuse.
(This is know as a series lamp.)

Now when your short circuit appears the lamp will light.
Saves alot of fuses.

Start tugging on wires and unplugging things.
When the lamp goes off you found your problem.

 

Easy and good idea, Thanks for the recommendations. IF it stops raining here in San Antonio area ill try to look at it tonight. Thanks again.

 

Trying to delte new post....diregard this post. Still trying to figure out the problem.

 

OKay, I have unplugged all bulbs in the rear of vehicle, except License bulbs. I have unplugged Turn signal switch in steering column, also took out Flash on fuse box. And unplugged rear backup switch on side of tranny.

I am getting a continuity on the fuse on one side after all this, what does that tell me if anything?

 

Is it the same side that has power (as in, if you put your meter on volts, would it read 12v to ground?). If the key is off, you shouldn't have power to either side of the fuse. Wondering why you didn't remove the front turn signal bulbs as well.... shouldn't matter much, if the turn signal switch is removed. Anyhow, if that is not the case, it tells me that there is a hard short to ground, which could be as close as underneath / behind the dash. You could also have a wire or wires that were nicked where they penetrate the firewall. Or there could be water in a connector somewhere. You'll probably have to trace through the wiring to see where the problem is. Apparently, this is not going to be a very easy fix and may take some time... like a good fairly clear sunny dry day... maybe ALL day.

 

I have 2 black wires that run along the wires that go to the rear wiring harness that im not sure what they r for....They are Completly black, can i assume that they r ground wires?

 

That, or someone's (no offense) "redneck fix" to a problem that might be causing your problem(s). Only way to tell is to trace those wires from end to end and see where they go from and to.

 

I agree!

What you can do, is disconnect the harness to the transmission and to the back wire harness under the hood at the firewall.

Then make a jumper clip with a ATC (square) fuse (10 amp = more then enough) and clips at both ends.

Clip one to battery positive, then take the clip and attach it the female bullet on the harness going to the back lamps. That will tell you what circuit is causing it to blow by going to ground. Hook to the battery first to avoid sparks at the battery or ARCing on the battery terminal.

Or use the jumper clip between the harness from the steering column and the harness to the back, under the hood. The reason for doing this is because if you go directly from battery to the reverse connector, you can tell if the short is from the harness forward or the harness back.

Have you removed your left tail lamp and looked at the ground there to make sure it is good (from memory I think this is where it is).

> THe fust still blows with the flasher being pulled

I have not followed the thread since when, but, I want to mention this.

You have two flashers --> AND <-- the brake light circuit. Without looking at a diagram to be sure, but, on most Fords the brake light circuit gets its power from one of the flashers indirectly on a red or red with white strip wire.

This might be as simple as a <$10 brake lamp switch.

 

Need to look into rebocards post....But what i have done is pulled the inline clips to all front and rear tail lamps, pulled the harness away from the steering column, also pulled reverse switch off tranny, Once key is turned on the fuse is still blowing. I also pulled the brake switch and fuse is still blowing...