I recently bought a 96 Disco.
Mechanically everything is sound but now I'm experiencing what can only be described as a casacading electrical fault.

1. Originally the only thing I noticed was that the side marker lights did not work.
2. Next, the turn signal indicator on the dashboard failed to illuminate. (the blinkers still work, but the dash doesn't tell you that they are on.)
3. Then, while driving a trail in the mountains, the hazard lights came on all by themselves. I could not turn them off, so I pulled the fuse under the hood. The lights stopped flashing, but the relay under the dash kept clicking. This went on for 15 minutes before stopping of its own accord.
4. A week later, I noticed that the lights no longer flashed when I lock the doors.
5. A day or two after that, it refused to start altogether for a short while.
6. The cruise control does not work, but this may be unrelated.

I located the green box under the passenger side dashboard where the relay noise came from. It seems to have been attached at one point in the past, but the mounting tabs were both broken so it was hanging loose. The guy I bought it from had modified the rig for off road use so I assume it has taken a serious beating hanging like that.

This part seems the likely culprit ($400 on Atlantic British) but If anyone has any further input as to the cause, I would greatly appreciate it.

And if this part is the issue, perhaps someone knows a better place to acquire it than Atlantic British?

I considered the turn signal control stick, but this would not affect the alarm , engine etc.

All the fuses seem perfectly good.

Thanks.
-C

 

I don't think all of those things are related, but the not starting, and the hazard lights and all of the clicking are probably that green box. It doesn't like to bounce around and dangle. I'd try securing it somehow. My 96 would act goofy when that box would bounce around. If that doesn't work, you may need to replace it.... but I don't know if it's plug and play or not. I saw a post just today from P.T. Schram about repairing corrosion on the main ECU, resetting adaptive values, and then he was putting it in "security learn mode".... You should check with him over at discoweb or landroversonly and see what he thinks, and if you have to have your ecu set to learn if you replace that box. Heck, he might even have a used one to sell.

 

A couple of things I would suggest, as far as used parts, I have had great service and prices with Will Tillery, the ROVERGUY.COM. Also I just ordered a 4 bolt flange kit (used) from Paul Grant at 203-770-1699, my first purchase from him, but also a great price.

I do know from experience, that the turn signal stalk can be the culprit for a combination problem as follows, brake lights and side markers will come on at the first position, but will go out along with the dash lights going out when you switch the headlights on. Mine did that and I got a used switch from Will. Problem fixed for under 50 bucks.

I realize your problem is not identical, but may be related. I would secure that loose item as well as double check all the associated grounds and look for damage / corrosion / modifications that may have been made by others. That sort of thing.

Have you downloaded the RAVE. It does have a detailed electrical troubleshooting manual and their own version of circuit drawings. I do not consider them to be a very goodd schematic due to the fragmented way in which they do it. But if you study it, it will finally make some sense. Guess you need to be British....

 

Reset the inertia switch on the firewall, passenger side.
When it is tripped it will set off the hazards, if it is completely tripped the engine will not start.

 

Thanks everybody for the help. Sorry I have not gotten back to the post until now.

I reset the inertia switch on the firewall. It had no effect at the time, but I will definitly keep it in mind if the hazard lights get posessed again!
(I didn't even know such a thing existed. Price of being a noob I guess.)

I have considered the headlight control stick, & I may need to replace that as well, but it will have no effect on the Alarm/locks/horn. (the horn has now gone out as well. It worked a few weeks ago!)

So, everthing seems to point to that green box banging around under the dash. (the Alarm ECU apparently.) I have no idea how long it has been loose, but it shows signs of excessive vibration (lots of scuffing around the mount points inside which center the circuit board inside the case.) Which is a surefire way to frag most electronics.

So, I'm taking Danny Lee's advice of trying to buy from will Tillery or Paul Grant. Otherwise Atlantic british it will have to be.

My only other thought was trying to test the unit in question, but short of swapping it out with someone elses, I have no idea if it is even possible.

 

You may want to do "Exploratory Surgery " on it and see if you can salvage it, why not if you plan to get another one anyway, You might save it. I have managed to revive similar gear with some good old redneck re-engineering.

It is amazing what you can do when you have to!!! I have used Will Tillery several times, just bought from Paul as well last week.

 

One other possiblity with any electrical circuitry is the ground points. Some of the Discovery ones will corrode badly and give you nightmare cascading types of problems.

Also the LR harnesses are very poor excuses for wiring in my professional harness building experience, but my background started with Naval Avionics/Flight Controls and ended with Manufacturing and Reliability Engineering and FDailure analysis of Electrical Systems on the Tomahawk Cruise Missile. I personally was involved withthe production of over 1000 Tomahawks from 1983-1993. So my standards of wiring are much higher than the average redneck.

The LandRover harnesses are poorly constructed, poorly routed and have multiple splices internal to the harness that are poorly insulated. If you have had exposure to wet conditions, that could very well be the root cause of your multiple problems. Worth investigating in my opinion!!!!!

 

Well to advertise my ignorance yet again, where should I begin looking at the wiring? Do I just start at the alarm ecu box and backtrack everything or are there particular known trouble spots? What kind of grounds am I looking for? Wires bolted to the chassis?

My dad is in avionics as well (QA manager actually), so I know a little about electronics, but...

As such, I don't thing I'll be going into the ECU box and noodling around too much. I can say that when we inspected it, He said all the solder was original production (IE, no one had been in it trying to replace components or anything like that.) The problem is that this is my only vehicle at the moment. It still drives fine, but without the box in place it won't start. So if I screw it up worse, I'm out of wheels.

Aside from the box I figure it would be in my best interest to go over the wiring before spending $400 on a part that may not be bad.

 

Okay.., Update.

I'm apparenty a bigger moron than at first suspected.
When the hazard lights first had a freak out, I ended up pulling the fuse under the hood so they did not flash while I drove down the road.

Well apparently, that is ALSO the horn fuse. So in replacing it, the horn works again, and now that the horn works, the side lights flash when the doors are locked (meaning the alarm works again I guess?)

So this leaves us with side marker lights that do not work, and that one episode of posessed hazard lights and one instance of the truck not starting.

That being said, the hazard light occurance was offroad on a "rollercoaster" mining trail. Very possible this pissed off the inertial thingy (still not sure what that is for.) As for the morning it didn't start, well, it IS a landrover, has to do something quirky now & then I suppose.

So now, back to the possibility that the side markers are due to a bad headlight switch? That leaves the intermittant turn signal indicator lamp on the dashboard (possibly a loose bulb/wire in the dash) and the cruise control which may never have worked to start with.

I'll try tracing wires when it's dry out.

Some days you figure out how little you actually know.

 

Aren't you glad you didn't go spend $400...