Annoying electrical/lights issue....

Okay, so its the joy of electrics on our 1986 Defender 110.
Here is the problem.....

When I have the headlights off, if I use the indicators, both headlights flash in time with the indicators (but neither side headlights work).

When I have the headlights off, if I break, both main headlights come on in time with the break lights, and go back off again when I take my foot off the break pedal (again neither side headlights work)

When I turn the headlights on, the indicators and break lights don't work. The passenger side-headlight works now but not the drivers one, but it is not a fault with the light as I have tested it separately)

Any ideas?

have you checked all the earths for everything?? just finished rebuilding a 90 and when i was doing the electrics had all sorts of whacky problems where things wernt earthing great.

check the headlight and indicator connections (incl earths) at the front. then the indicator and brake connections.

also check the condition of the main light switch connection.

one poor connection can be the cause of a world of pain......

Okay so have managed to solve the break light + headlights problem, found out some things were wired up crazily. But am having some other problems now which I hope somebody may be able to help with:-

When the headlights are off, the indicators work normally.

When the headlights are on, the drivers side indicators (front, side and rear) come on as headlights (i.e they dont flash and stay on permanently) and if I try to indicate right they still dont flash, they just all stay on. The passenger side ones dont have any problems, they just work normally when I try to indicate.

When the headilghts are on, however, if I put on the hazards, all indicators flash normally as they should, including the drivers side ones (which dont flash when I try to indicate with them on their own, as I said above!).

Have checked all of the earths and connections to the best of my knowledge (which to tell the truth is terrible when it comes to electrics) but was hoping that someone may be able to suggest what may be incorrectly wired up by reading the symptoms? Or any advice at all would be helpful!

Sounds like you still have an earthing problem.
The wiring is split in two, so the left hand side and right hand side should each have their own earth.

I'd say from your description it's your drivers side headlight that has a bad earth, so it's time to re-check and clean up the connections on that side. And make sure that the earth inside the wing is connected.

sounds as though the hazard switch is good - which means the indicators should be ok.

check the earthing connection on the inner wings.

keep us posted

Have you by any chance replaced any bulbs recently?

I once accidentally put the wrong type of bulb into the back light of a Sprinter Van and everytime I pressed the brake all the lights would come on......... The bulb was shorting over between the brake light and the side light wiring.

To continue on this theme... rear (right) indicator bulb stopped working. Sorted dodgy shorting contact whereupon all indicators stopped working. Hazzards do still work though. Checked 5A fuses & ok. No power getting to those fuses though. Haynes maunal shows additional fuses under seats etc but apart from engine management electrics I cannot find any. Checked big maxi fuses in engine bay and they are ok

Any help appreciated

So why the hell are there two fuses controlling the indicators? 15A fuse that also powers fuel guage (which is how-come I tracked it down) also powers indicators before the power goes through the two side-specific fuses mounted just below duh!!

In my battle with the electrics over the years, I have added in several extra earthing connections to the wiring which have helped keep things running.

I've simply linked a wire from, say, the headlight earth wiring up to a convenient bolt on the edge of the engine bay.

Okay so traced the earth wire back to the bulkhead, cleaned up the connectors and around the earth, then reconnected it back how it was before I cleaned it, then it blew the fuse and none of the headlights work on that side at all (even after changing the fuse) but the indicators do still work, unless of course the headlights are switched to be on, in which case they dont come on (presumably for the same reason as the previous problems)

Any ideas?

My money is still on a dodgy connection - probably the earth inside the wing.

These are a right pain in the arse!

Ive had a very similar problem with my 93k defender 90 recently,lights not working,fuses blowing all sorts,turned out to be the main earth,where the earth comes out the battery compartmentand runs along the chassis rail to the gearbox there is a crimp what earths it to the chassis,these are a common fault,i put a new earth strap from gearbox to chassis and its sorted all the electrical problems out

just about to post a question myself about the very same thing that has happened to me tonight with lighting issues, so not really wanting to start a new thread or high jacking this one........sorry...... This evening experienced all of the above mentioned issues plus....when i turn the engine off with the headlights on....nothing happens, remove the key and everything still running....with the key still out i then turn off the headlights and this switches the engine off.....ive just been to see paranormal activity 2 down the odeon but hoping this is a easy electrical fix rather than needing a drop of holy water in the rad.....Any ideas.

Fixed the indicator problem, now the only problem is.....

When I put the headlights on in main beam they all work fine, both front side lights and hedlights.
However, when I try to just put sidelights on, only the passenger one works, and when I try to put all headlights on in dip-beam, again only the passenger one works. I have tried all of the earths, looked at connectons and nothing seems wrong to me, but obviously something is wrong since they arent working.

Another problem is that the fog lights arent working either but I dont know if this is connected or not...

Have you tried swapping the bulbs just in case. Also wd the bulb holder.

With regards the fog light start at the switch and try to isolate the problem - my fog light wasn't working due to a poor earth on the towing electrics!

Farty, my money is on a dodgy ignition switch.

Have tried swapping the bulbs, they arent the problem. Re: bulb holders, would that be a likely cause since both side and main headlights dont work on that side? And they do work on main beam, just not dip beam, so would it be down to the holders....

Have you checked the earth that is connected to the inner wing?

Definately spray wd into the bulb holder and the connections on the back.

Are the main earthing strap on the chassis and gear box ok?