Jump to content

Shorted Wiper Now Blowing A Fuse - Help


itllbedonesoon

Recommended Posts

Hi,

 

When reconnecting my wiper motor I did not connect the live feed correctly, it came off at some point and shorted with one of the other terminals on the wiper motor or on the wiper body.

 

Problem now is the 15 amp fuse on the loom keeps blowing every time I try to reconnect the battery. I am guessing the short from the wiper motor has done some damage somewhere creating a short to earth.

 

I have the VG loom, which came with a 4 fuse holder, this is the 15 amp that keeps blowing. There are 3 relays and a 3 pin ford flasher unit.

With the battery connected and no fuse I am getting constant live 12v to one side of the fuse with the ignition off.

When I go to ignition 2 (15 amp fuse missing) I am getting no power to the sierra dash lights, the hazards don't work, wiper does not work.

headlights do work.

 

I have no idea how to find where the short is or how to go about tracing it through the myriad of wires under the dash. Can anyone please suggest a possible way to locate the problem (apart from looking in a mirror)?

 

Thank you

Link to comment
Share on other sites

A few questions for you to answer.

 

Is it the mini wiper motor fitted if so try removing the plug from the unit.

 

The mini wiper has a switch for the park position and may have welded the contacts together.

 

You need to trace what is causing the fuse to blow be disconnecting parts in the circuit to find the fault.

 

Regards

 

Martin

Link to comment
Share on other sites

First without the fuse and ignition off disconnect the wiper wire from the wiper motor and put a bit of tape on its end to insulate it.

You have a multimeter? By this statement (You are getting constant live to one fuse terminal. Supply terminal.)

Check what you have at the distribution terminal of that same fuse. Mutlimeter on Volts 20, probe the terminal and other probe on earth. No volts would be good.

Now set multimeter to ohms and repeat. If this shows single figure ohms reading then the wire from that fuse to the motor has cooked itself and goes to earth. Where??

Remove the covers round the steering column and pull the plugs off the column stalks. Now do the same fuse distribution terminal to earth ohms check.

If it still goes to earth the wire is fried/earthing between the fuse and switches. If it however shows no earth do next.

Next do probe into the end you took off and insulated at the wiper motor and earth the other probe. If low resistance then the wire is fried between switches and motor. If this shows high resistance/open circuit its switches or motor.

Link to comment
Share on other sites

Thank you for the responses:

 

The wiper motor is from a land rover i think, it is a lucas 5 pin worm drive gear type. It does not look like the connector comes off it appears attached to the wiper motor.

 

I have tested the connections with a multimeter,

Fuse supply terminal to earth = 12.57volts

Fuse distribution terminal to earth = 0 volts

 

I then disconnected the battery (as I read you are not suppose to check resistance on a live circuit?) connected the red multi meter to the fuse distribution terminal. all tests were done at the 200 ohm setting on the multi meter:

 

fuse supply to earth = infinite

fuse distribution to earth = 0.89

 

Column switches disconnected, connecting the distribution fuse terminal to the column switches connector wire as follows:

 

Indicators & dip switch side

to 54 = infinite

to R = 0.90

to 30H = 0.2

X

to 49 = infinite

to L = 0.9

to 49a = infinite

 

to 31 = 0.9

to 56a = infinite

to 56b = infinite

to 56 = infinite

 

Wipers and lights switch side

to 56 = infinite

to 53.2 = 18.1

to 58 = 1.2

to 53c = 0.3

31b.2 = 18.1

to W = 0.4

to 30 = infinite

to 53a = infinite

 

31b.1 = infinite

53 = infinite

54 = 18.3

53b = infinite

 

Then testing the wiper motor wire with the column switches still disconnected:

Earth = 0.3

Park = infinite

fast = infinite

12v supply = 18.2

slow = infinite

 

Unfortunately with very limited electrical experience I do not know how to interpret the figures as there seems to be varying readings in each column connector group and also up to the wiper supply wire?

 

Thank you in advance for any further advice,

Link to comment
Share on other sites

From the readings from fuse distribution, 54 and terminal 4 wire 12v supply at the motor end your short is somewhere along this wire. Looks like a blue/green in the VG loom. I would follow the loom as best I could working back from the motor to the switch paying special attention to any bends, areas it goes through holes in bulkheads, sniffing for electrical burnt smell and looking for damage/signs of heat.

As a test it would be worth getting a length of wire, cutting the blue/green temporarily out leaving a two inch tail still attached at the fuse, the column switch plug and the motor plug. Then connecting those three points with the new wire.( Yes I do mean all three should be joined together.) Plug everything back in and see if the fuse survives and the wipers now work. If so it might even be easier to leave it like that and making it a more permanent repair. But it's useful for confirming the fault. Checking the loom would take much longer and would show any areas of lesser damage that may lead to problems in the future.

Good luck,

 

Nigel

Link to comment
Share on other sites

ok, I checked the blue/green from the wiper motor tracing back to the column switches. Unfortunately (or fortunately depending on the circumstances) there is no bulkhead to transition between the wiper motor and the column switches and the loom is partially encased in ribbed sheathing (or was until i pulled it apart) so it would struggle to ground unless off another wire. While checking the wire I did a continuity check from the blue/green to earth and it was not showing as grounding.

 

I checked the other wires from the wiper motor for grounding using continuity and the 12v live feed was earthing. This comes in to the wiper on a green from the VG loom and green I believe is pretty much the live circuit for all the ancillaries! I checked separately the washer bottle, foot brake switch and wiper motor and all were showing as grounding.

 

I started tracing the green and low and behold, hidden in the tape in the loom it joined a cluster where it seems all the green wires in the loom are interconnected. I started separating them 1 at a time until I lost the earthing. I traced this green wire to the sierra instrument cluster. When I disconnect the green from the instrument plug connector, I lose the grounding in the the green wires.

 

I disconnected the plug from the instruments and tested with continuity to earth all the wires. About 10 of the 12 are showing as grounding. :shok:

 

However, now I am getting lost from seeing the forest because of all the trees, I guess a circuit has to ground at some point to complete the circuit back to the battery. I am worried now that the wires out of the instrument cluster are the return wires that is why so many of them are grounding with a continuity test even with the plug disconnected.

 

I also tested the problem 15amp fuse terminals (with the instrument plug disconnected so my green circuit is not grounding) and the distribution terminal of the fuse is still showing as grounding.

 

So this leads me to believe:

1. the grounding is not in the green circuit supply to the wiper motor.

2. It might be a fried column switch which is why so many circuits on the instrument panel appear to be grounding.

3. continuity testing to earth on the various circuits was not the right thing to do and I have confused myself. :crazy:

 

My bets are on No.3.

 

I ran out of time but will try disconnecting the column switches and see how that affects the grounding on the instrument cluster connector and then I am out of ideas... :help:

Link to comment
Share on other sites

If you haven't disconnected the loads from the circuit under test all 12 volt feed wires will show a low or very low resistance.

 

With 12 volt testing I use a high wattage lamp ( headlamp or 2 x 21 watt flasher lamps ) in place of the fuse ( one side of test lamp connected to feed side of fuse & other side of test lamp to load side)

 

With this set-up all possibilities can be tested " hot" -- a dead short will only make the test lamp shine brightly & any other lamp or motor will glow dim or run very slow. There will be no additional harm done to your wiring as the test lamps limit the current to a maximum of lamp wattage divided by 12 volts ( 2 x 21 watt flashers = 3.5 amps ) All the loom wiring should be good for 10 amps. HTH

Link to comment
Share on other sites

You were sure the short occurred when it slipped off the motor and touched earth.

 

From the readings from fuse distribution, 54 and terminal 4 wire 12v supply at the motor end your short is somewhere along this wire

To expand, this wire comes from the distribution side of the fuse and goes to the left column switch (terminal 54) and the wiper motor (terminal 4). Its ignition live in VG loom. It's green not green/blue. Sorry I identified it wrong as green/blue.

 

I started tracing the green and low and behold, hidden in the tape in the loom it joined a cluster where it seems all the green wires in the loom are interconnected. I started separating them 1 at a time until I lost the earthing. I traced this green wire to the sierra instrument cluster. When I disconnect the green from the instrument plug connector, I lose the grounding in the the green wires.

(VG has it going to numerous items which now don't have a supply and all their green supply wires which branch off this one will test as shorted to ground. Try not to worry about them. They are unlikely to be damaged themselves so don't need to be investigated at this stage.)

 

At the moment I think your car is as follows.

One fuse blown and removed.

Column switches unplugged.

Wiper motor unplugged.

The various greens that branch out from the 'cluster' you found are still connected to the loom but you have unplugged the instruments.

 

Testing at fuse distribution point shows ground.

Testing the greens in the cluster shows none of them grounded.

 

If this is the case then the cluster greens are no longer connected to the fuse distribution point. To me that suggests the short is towards the fuse end of the main green supply wire and has cut it.

 

So I would start at the fuse end of the green wire and work along the loom following the green wire till you find the short/break.

 

 

 

Link to comment
Share on other sites

Thank you for all the advice, I started again but this time starting from the fuse distribution terminal as you advised and followed that wire. It forked and I disconnected one of the forks further along the loom and checked for grounding on all the connections. It was grounding down the other branch, I followed this wire and it took me to the car horn switch in the steering wheel.

 

The wire was grounding where is passes past the dash board and lies on top of the steering column and key barrel Ha ha!!! and unfortunately also the car horn was busted. I have ordered a new car horn and sorted out the grounding. So all good.

 

I tested the horn circuit wiring in a bulb in place of the broken horn, all good and the wiper motor still works and no blown fuse! :D

 

Although now my indicators have stopped working, I have hazards but no indicators. So I will try to look at this tomorrow.

 

Thank you for sorting out my blown fuse as I have no idea with electrics and did not even know where to start. :good:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...