Tricky side-lights problem

Peter wrote:

Faulty trailer socket wiring?

Trapped wiring?  Have you changed any light fittings or bulbs recently?
Fuse overloading when brake is pressed?

Martin

Peter wrote:

Just a wild suggestion - I had a car with an alternator overcharging and
it blew quite a few globes, maybe one or two more often than the rest.
The big hint was brightening of the headlights at times.

Hi Guys

I Had The Same Problem with my 200 disco the Bulb holder was The Offender
after Changing the Foot  brake Switch

Regards

Skinty

Thanks for all advice,
EMB, I've had a good fiddle with the socker but can't find anything
untoward.
Oily, I've inspected all the light fittings and refitted them, the front one
is pretty crappy but doesn't seem to affect anything when I pull the wiring
about. I don't think it is the brake lights as they are on a separate
circuit.
Jg, It is only the one fuse that keeps blowing so I believe it is something
to do with that circuit, and I dream of the lights brightening!!!
Skinty, I am looking at that dodgy front light fitting again, but as said,
don't think it involves the brakes.

I've tried every permutation while stationary to replicate the fault:
Swithing different lights on and off, turning the steering lock to lock,
applying the brakes, putting her into reverse, turning on the rear fog light
etc. etc.
The fuse seems to blow at random when on the move sometimes it lasts for a
couple of days (i've been running with the lights on during the day as a
test) and then it goes again, usually at night!
It started happening a couple of weeks ago and had never been a problem
before.
The fault must be after the fuse holder otherwise it wouldn't blow, I am
surprised that so much wiring is unprotected before the fuse! If I can get
to the back of the appropropriate fuse I should be able to renew the wiring.
Then if it still blows I'll "know" it's a light fitting.
What a bugger!

Cheers,
Peter

I had a wire that was worn through where it jiggled against bodywork.
Took me ages to reproduce it at rest.

One drastic method would be to put a bigger fuse in, at the risk of setting
fire to your car of course.

TonyB

Did a rover 800 that kept blowing its ignition fuse at random intervals.
Put a headlight bulb in the fuse holder instead of the fuse and told him to
keep an eye on it (bright bulb means short circuit) but he kept it like that
till he sold it ages later and never had another problem with it :)
--
Jon

jOn wrote:

I had a very intermittent fuse blowing time with a P38 RR.
Three or four times a year it would blow the fuse supplying the brake
lights when the brake pedal was pressed but this fuse also supplied the
climate control (HEVAC), ABS ECU and some of the dash indicator lamps.
Sometimes the replacement would blow straight away, sometimes it would
be OK. It would always stop blowing as soon as I started to try and
trace what was causing it. It seemed to happen more in the summer so I
thought maybe summat connected with the climate control. Eventually I
systematically spliced some in-line fuses of a lower rating in each of
the splits to the different circuits. Next time the problem happened I
had isolated it to the brake lights, turned out it was the wire feeding
the high level lights in the tailgate was crushed under the tailgate
trim near a fixing screw. It was worse in summer purely because of the
tailgate materials getting hot and expanding when the vehicle was left
in the sun.

Gaz

Tony, I've been working up in fuse sizes and so far have reached 20 amps and
still blowing.
Jon, had to sit in a darkened room for a few minutes to get used to your
idea, I'm going to give it a try as if nothing else it will tell me exactly
when the short circtuit occurs.
Thanks everyone,
Peter

As you say it's a 90 then it should have a diagram of the fuses and what
they are for on the back of the plastic cover. What circuit/s does this
particular fuse run? If you can tell us that then we may be able to give you
an idea what is wrong and how to test for a fault.

Martin

Oily wrote:


I have a 1996 workshop manual brilliant - only a circuit diagram for the
alarm system!

At that vintage which'll be 300Tdi, I guess and therefore later than
yours, the side lights are fused separately LH and RH with nothing else
on the circuits. The number plate light will be on one side or the other
- don't know which.

I also have a very early 90 circuit diagran which may be 200 Tdi. This
again has the LH and RH side/tail lights on separate fuses by side. The
number plate light is in the LH circuit. There appears to be one
connector in the line out of the fuse box (where front and rear are
spilt off) other than the connectors immediately before the light units
themselves.

If you can find this connector quickly you'll be able to isolate the
problem to the front or rear part of the circuit.

If you can't quickly find this connector I'd start by dismounting the
three lights units (or two if you've worked out that it's the RH side
without the number plate light) and visually checking for obvious short
circuits there. Then work 'backwards' following the harness looking for
rubbing damage until it becomes too difficult to check easily. If you've
found nothing damaged by that point you should have located the
afore-mentioned connector. Open it up there and see what you find in the
three legs separately.

If the OP wants a copy of that circuit diagram drop me an e-mail to my
address with the obvious change.

Dougal wrote:


As EMB suggested earlier if there's a trailer socket -  particularly of
the ripped off, dangly variety or if only the wiring remains - that's
the prime suspect. Check it first.

On Wed, 16 Jan 2008 09:14:24 -0000, "Peter"


Could the onset of this be related to the wet weather?

Just recently my 90 has been blowing fuses in the indicator circuit.
It's taken a lot of searching and stripping down of the indicator
switch which has improved it's mechanical functionabilty a lot - but
alas not cured the fuse blowing.  Upon suggestion of my local Landy
mech, I checked out the hazard warning switch - couldn't find anything
wrong.  Had all the lights out and checked for shorting, earthing etc.

The fault is not consistent, but started immediately after a journey
through a particularly heavy downpour.  Operation of the left
indicator would sometimes blow the fuse immediately, sometimes only
after several operations.  Operation of the hazard warning switch
would blow two fuses at once!

Anyway, long story short:

I have now found the cause, and it is a badly sealed connection in the
wiring to the nearside rear lights.  Upon opening it up, it is very
wet and corroded around the wires.  Separating and drying the wires
has cured the fault, next job is to clean, re-connect and seal
properly the connectors.

So, in your case, take a look along the top of the rear cross-member,
for a section of wiring loom going to the rear nearside lights - you
might get lucky and find your cause there.

Neil

(Reply via NG please)

I know it's the left side lights and fuse. Trouble is it's intermittent. The
fuse blows and I fit a new one and it's OK. Then it blows again after an
unspecified period.
The trailer socket is on a different circuit, so I know it's not that.
I've traced right through and been unable to replicate the fault.
What I have done now, is cut into the circuit under the bonnet and behind
each light, then rewired between with a complete new circuit and so far it
hasn't blown again.
The Haynes manual wiring diagram seems to be accurate but if it is I am
surprised how much wiring isn't protected by fuses - the instrument lighting
for example.
Thanks everyone, if it blows again I'll report back
Peter

Peter wrote:

Em!  The trailer tail lights pick up off the vehicle circuits(unless you
have something really unusual and probably not standard). Anything from
the pickup points back to the socket is suspect. Think again?

You may well be right. But I can definitely say that they are not in the new
circuit!
However, this gives me another idea. I'll plug the trailer light board in
and keep it in the back and see if that blows. It will certainly help to
narrow things down further.
Cheers,
Peter

So far so good. It's been a week and the new circuit hasn't blown.
I checked the lighting socket last night and everything was working even
though I have bypassed the normal lighting circuit. So in this case it is on
a different circuit as I thought. It may not be correct, but that's how it
is!
Thanks again to everyone who chipped in!
Peter