Electrical Woes - 110 300TDI '97 - Dash related

Couldn't find a 'sparky' part so hopefully this will do the job, if not feel free to move ta.

Bit of a long follow on this from other issues but i've got me some interesting to say the least dash issues come on! Which almost got worse overnight somehow or more likely i didn't pay enough attention and it actually happened since i got the truck. Long story short.. Truck lost all its coolant etc and now i'm looking at the guage every 2 seconds where as i didn't before.

Let me describe what i have going on at the moment. Its worth noting at this point looking through receipts i have the previous owner had an indicator stalk fitted last year.

My guages and lights are now coming on like christmas tree! The fuel guage as soon as the ignition is turned on swings full right aka full past the white marker, so operations from both ends of the scale.

The temp guage once warm gets effected by different operations of the dash too. (having had cooling issues this is my main worry at present to be honest)

If i for example turn the heater on one or two it also changes things,, either the dials themselves or addionally lights up the bulbs for the lights, headlights and foglight. Sometimes the glowplug light too.

Different things doing different things to my dash, having lifted off the front i can't see any loose wires etc and to have that many loose wires seems odd at this point and seems to push towards a ground fault?

When i turn the lights on via switch, the lights come on fine etc and the dash lights up but not everytime does it light the bulb to the panel, that or its very dim (not tried this in the dark - quick 10 mins testing this morning)

Turning the fan on or turning on the lights will ping the fuel/temp guages around.

I've probably missed some stuff here but i thought i'd see what you guys come up with on a common ground area etc or if thats what you think it is too.

Cheers,

Mark.

seems like bad earth for dash gauges etc

To add, parking brake lights up as it should and isn't effected.

Glow plug light comes on with ignition as it should and isn't then effected.

Diff locks doesn't come up on the dash.. could just be a bulb thing.

indicator left or right at first click also shows up the trailer light, not sure if thats normal or not? but only for first cycle.

Where is the common grounds for all this? All just sinks into one big loom down to the fusebox i guess?

As said, earthing problem I'd guess, but I'd check the indicator stalk wiring too though ... look for not just wrong connections, but frayed or broken wires too.

Trailer light shows on first indicator until there is a trailer actually connected, then flashes with the indicators to show the connection is working.

Cool stuff.. it was worth asking or i'd spend hours figuring out why it was coming on too!

Fog comes on when i activate lights too.. like bulb on dash but fog doesnt come on from outside

Coffee Addict said:

Cool stuff.. it was worth asking or i'd spend hours figuring out why it was coming on too!

Fog comes on when i activate lights too.. like bulb on dash but fog doesnt come on from outside

Click to expand...

Plus another one on that earthing problem, every light on your dash panel shares an earth all bacck to one point, if that earth is weak, then the power takes path through all or many of the other bulbs. It can sometimes take a bit to find unfortunately.

I am thinking its a 'one point' situation, but i can't as yet find that damn 'one point'

Spent an hour yesterday having a fiddle and seeing what else i could see and or trying plugs etc..

Yesterdays findings gives me this to add to the list

When started, the battery light stays on but is dim.

Having taken the plastic off the steering column and disconnected all the plugs, none of them make a difference to the dash.

Behind the dash everything is connected and looks fine, nothing broken or touching.

Dash removed out the way of the fan switch, still does a disco when you use it, so its a 'power' thing rather than the movement upsetting a cable.

I found an earth point in the engine bay, one earth went to a little relay of sorts next to it but one earth elsewhere.. Disconnected those, made no difference to dash so thats not the magical one i'm looking for.

Other wires went across the bulkhead behind a little plastic jobby which then it appears goes down to the fusebox.. Seemed a bit weird this? Why doesn't the loom just go from dash down to fuse, running it through the bay just seems a little odd.

When at the fusebox, i can't find a ground off this?

All in all.. a big FAIL! Couldn't get anything to ground out or change its manner, either by not reading or fully reading or turning on off lights etc.

What have a missed here except everything?!

battery light could be a altinater packing up have you tried getting a earth wire direct from battery then find none live side of panel instriments and connect to it what happens now

Ok, further developments.

Ran a continuity test - all grounds I tested so fuse box to neg, bulkhead bolt to engine block, some neg's off the gauges to neg battery. All showed fine.

Turn the ignition on however, the grounds on the gauges was showing open circuits. Popping a cable direct from back of guage to battery neg made no difference once ignition was on.

Behind the dash with the bulbs was 2 big plugs going to them, disconnected those, made no difference.

What I failed to look at was the fan switch itself, was the only thing I didn't disconnect throughout the process so I'm hoping this is it.

Only coming to that conclusion because of the 'ground' tests I am now assuming the fault is on the positive side somewhere and bleeding to ground somehow.

I did also remove the bulbs from behind gauges 1 by 1 to see if somehow one of them was shorting or something - again I have no idea I was just fiddling really.

When I've 5 minutes again i'll report back on disconnecting the fan switch and see what happens there.

If this has popped up any other idea's then fire away too!

Down at the 'fog light' switch, I disconnected the wires to this as well - the fog light was one of the bulbs coming up on the dash during these errors. The switch itself is faulty as doesn't click into place properly. This however is now eliminated from the circuit. Worth noting, during 'fog light on' times (when lights are switched on) the actual fog light doesn't come on, only its dash bulb. All other lights operate as required/normal.


Cheers again,

Mark.

hi on looking at 1986 wiring diagram there are no in line dioads but weather later ones had them I don't know if you find wire with small bulge it could be in line dioad some times they can break down I haven't got later wiring diagram to check

Have been taking care of the cambelt for the moment so once again not touched it. When i was looking around i didn't see any that i could remember.

Shame ive not got the pennies at the moment for the new guages i want, that way i'd have a good excuse to strip out the dash and install the new stuff and wiring etc and would all be exposed and could plumb it all in and volia! You guys running centre consoles or whatever you class them as for your extra guages and sterio etc, do you sacrifice the drivers side front vent or do you kinda try and square it up between the two? (Just an off thought while im at it hey)

As yet to try the fan as the last bit on that list. (And double check for diodes)

did later ones have any extra controle boxes that early ones dident have never worged on later ones hgv /plant mainley

As above - this is most likely an earth fault - which in turn is most likely a missing or broken earth lead or strap. It might also be a control box / voltage regulator issue - but IMHO earth fault most likely - and you loose nothing by making sure all the earth returns are tip top.
Worth noting that if you have a handbrake cable, then this can act as an earth return for a limited time.

The appropriate wiring diags will probably be on the web somewhere.

I'd confirm the presence of, and remake ( clean and grease with Vaseline ) all the connections of the factory fitted earth straps first. Then, if still "broken", I'd add extra earth returns to appropriate parts of the instrument cluster.

In terms of testing your earth returns - IME, this is best done under load - I.E. a headlamp bulb jury rigged to draw some current through the test point. IMHO, a DMM will be more or less useless in this regard, ( won't draw enough current to show any issues) .

Thanks for your replies.. got the other bits out the way so will be clear to look into this again as of next week.

Can someone tell me where the factory earth points are for the 110 defender? I.e to chassis etc as you describe. I'll go through them then and clean up etc and try them under load as you've suggested.

Cheers,

Mark

Edit -

Truck has been apart for a few hours this afternoon. Few extra funnies on the cards!

Im way past the limit of my knowledge here but looks like someones had a crack at this already.

On the passenger side of the car there has been an additional ground run which has spliced off just behind the headlight - this isnt factory but something very interesting happens when its removed and just relies on its original grounding. The windscreen wipers started to run when the lights/indicators and ignition was on regardless of switch position! So.. quickly removed dash cover to stop them moving and back to ind/sidelight. Main now disconnected obviously as we're at the plug. Soooo.. disconnect that secondary ground and the sidelight and indi change positions! So what was a static top and flashing bottom turns into a flashing top and no bottom.

Just lost guys.. fully lost.

I hope you get it sorted, i hate auto electrical problems, especially when you uncover previous bodges.

Coffee Addict said:

The windscreen wipers started to run

Click to expand...

Classic earth fault IME - normally engine earth strap missing - again IME....

make sure there are at least TWO large ( battery cable sized ) earth straps - one connecting the engine to the chassis - and one from the gearbox to the chassis. Also make damn sure the earth connection to the battery is in excellent condition.

EDIT to add - RAVE covers your vehicle - so will give you the positions of earth straps and earth points. According to this post:-

https://www.landyzone.co.uk/land-rover/rave-disk-maintenance-manual.260227/

you'll be wanting rave02.iso.....

Coffee Addict said:

Couldn't find a 'sparky' part so hopefully this will do the job, if not feel free to move ta.

Bit of a long follow on this from other issues but i've got me some interesting to say the least dash issues come on! Which almost got worse overnight somehow or more likely i didn't pay enough attention and it actually happened since i got the truck. Long story short.. Truck lost all its coolant etc and now i'm looking at the guage every 2 seconds where as i didn't before.

Let me describe what i have going on at the moment. Its worth noting at this point looking through receipts i have the previous owner had an indicator stalk fitted last year.

My guages and lights are now coming on like christmas tree! The fuel guage as soon as the ignition is turned on swings full right aka full past the white marker, so operations from both ends of the scale.

The temp guage once warm gets effected by different operations of the dash too. (having had cooling issues this is my main worry at present to be honest)

If i for example turn the heater on one or two it also changes things,, either the dials themselves or addionally lights up the bulbs for the lights, headlights and foglight. Sometimes the glowplug light too.

Different things doing different things to my dash, having lifted off the front i can't see any loose wires etc and to have that many loose wires seems odd at this point and seems to push towards a ground fault?

When i turn the lights on via switch, the lights come on fine etc and the dash lights up but not everytime does it light the bulb to the panel, that or its very dim (not tried this in the dark - quick 10 mins testing this morning)

Turning the fan on or turning on the lights will ping the fuel/temp guages around.

I've probably missed some stuff here but i thought i'd see what you guys come up with on a common ground area etc or if thats what you think it is too.

Cheers,

Mark.

Click to expand...

RE earth as much as you can from scratch.

hi I don't think this is your proplem but I had a case where one head lamp bulb had a broken filament which landed across other filament in bulb so one headlamp only worked on one filament other head lamp had both filament lit all time when switched on

Ok guys - next instalment!

Been busy taking care of a load of other things - including a new 90 now in resto mode! (Bit off way more than I can chew! - then new dog in the family means working time is minimal at present!)

I bought ages ago an EGT gauge so went about stripping back the stupid plastic cover in front of the vents etc so I can trace some wires and hopefully kill 2 birds with one stone. The guage is up and working and on an off note - driving shows about 250c and on a hill went up to about 350-400c. This is to my knowledge on a stock pump - this sound about the right reading or is my probe not in far enough do you think? I've popped it into my EGR blanking plate. If you happen to know that be ace, just a ball park to save opening a new thread - in searching all I could see was people debating how high you should go, rather than a baseline stock figure to make sure the gauge is behaving properly before fiddling!

Now - back to the electrical testing! (With help from a good friend of mine but I will write this as "I then did this" just to shorten what will be a massive post)

I took down the interior light so it was hanging facing the dash if that makes any sense - this way the circuit has a load as someone suggested and I could see what was going on with the bulb.

In normal mode the light has 3 wires - one is a permanent live, switched live and a ground. I know it sounds silly to mention all this but the more info I pass over and my 'workings out' may make it easier for you to understand my silly logic and what I was doing.

This was seeing around 12v in switched mode and about 8v in permanent on. Noticeable difference in brightness.

As I toggled the fan switch the bulb changed brightness and in some cases turned off all together. Went and got me a bit of wiring and off the ground of the light I wrapped it round and taped it there to see about boosting it direct to the bulb to see what happened. As I touched the bolt holding my sunvisors to back up the ground in the 8v position the bulb got brighter. Volia! Tinkering with the fan switch again however made the light do silly things. As a non reliable earth I took the wire down to the fusebox and touched it against the front as a more solid ground. This created a small arc!

My mind turned to the fan switch itself, a few fuses in there was a 15amp fuse and I pulled this for the fan and the arc stopped. So - something dodgy going on with my fan. This disconnected the bulb still showed around 8v until I touched the wire against a ground to back it up and showed then full brightness. In turn - my dash lights also for the first time was visable behind the speedo etc.

Behind the dash I found 2 big blue connectors full of wires, these I believe are ground connectors. Removing the backup wire and wiggling these around the light became dim to bright so I believe these blocks are the culprit along with a dodgy fan. The switch has been disconnected and I will just get a 2 position switch to wire that in with later once I've removed the heater box and figured out why that's arcing out. Maybe motor brushes gone bad or something. Annoying thing is my heater actually works good when on!

Anyway, these 2 blue blocks now the heater crap is out the way! The loose wires that run in the middle which used to go to the fag lighter and stuff, I found a switched ground and a constant ground - so using the constant ground wire I found I popped a cable into the spade connector then screwed that behind the bolt where the wiper motor is. This made the light go bright so I've boosted the ground for now and didn't have to drive with a cable hanging down from my light. This is a temp solution because of these blue blocks.

With the light now nice and bright and the fan no longer making an arc I felt a bit safer continuing on problem solving. As I wiggled these blue blocks it would flicker the interior light - but the boosted ground now means all my gauges etc on my dash are working as they should - in my mind its close enough to the source to have helped.

Can you confirm these 2 big blue blocks of wires are just one big ground distribution and by the sounds of my crappy explination that these have suffered ingress or whatever over the years and now making a bad earth?

Having a quick look online I found something like this;

https://www.ebay.co.uk/itm/20-Screw...826092?hash=item41e90d216c:g:wHAAAOSwNqJbYfwt

Its going to be a royal pain in the ass because I'd have to mount this elsewhere and do a whole heap of soldering to extend grounds but seems like the best long term plan? I also thought I could just connect a ring to each wire then hardwire them to the bulkhead - not sure what way round would be best or if there is infact other options?

Thanks for taking the time to read and respond - if I've not made something clear just pull me up on it and i'll try to explain further - or if I could do XYZ to test a theory then let me know.

I'd rather not pull those blue blocks apart until I've sourced a replacement system unless they do actually come apart and go back together again - didn't try this incase the answer was no!

The 87' 90 I purchased doesn't have these blocks so didn't help me for cross referencing (Old glass fuse crap which given my history i'll be pulling that and replacing it!)

Ta

Mark