Dash lights

[Captainoversteer]

Hi all, my '95 24v is giving me a headache! I have a number of dash warning lights(battery charge,timing belt,turbo,brake warning,oil level,fuel filter) on all of the time whilst engine is running,I've done a search and had alternator off checked/replaced regulator and checked/cleaned the earths either side of the block,both battery terminals,both inner wings next to the batteries and the drivers footwell all to no avail.

Any ideas where to go/what to do next? Both batteries are good,starts fine and is charging at 14.4v.
The manifold heater light comes on from time to time whilst driving,is this linked? I have disconnected the feed into the manifold and taped it up if it makes any difference?
I'm sure its an earth fault as I'd assume these warning lights are all switched earth but I'm obviously missing some thing somewhere.
Thanks in advance!
Dan

 

[frank rabbets]

I had this on mine at the same time my rear wiper packed up. Turned out to be a poor earth wire in top tailgate. If your rear wiper is faulty this is what it may well be.

Frank

 

[Captainoversteer]

Thanks Frank,I've read your thread and although I haven't been inside the tailgate to check,the rear wash wipe works as it should so I'm working on the assumption its ok. We all know what assumption promotes though don't we!? Lol.
Will have another go at it after work this evening,was a little annoyed with it last night!

 

[Captainoversteer]

Right,so Ive had another poke around tonight looking for more random earths,checking continuity etc. had both fuse boxes out but cannot see anything amiss.Ive chopped out some non standard wiring which I assume was an aftermarket alarm/immobiliser and a phone kit.
I then noticed that the 7.5A fuse in the engine bay had no power on it with or without the engine running so had the bright idea of jumping power to it.

The lights are all out!
Trouble being,with the exception of the timing belt light none of them now come on with the ignition
This doesnt bother me too much as apart from the battery light the rest are fairly non crucial anyway,just be nice to fix it properly
Everything else works as it should,charging etc.
Any ideas please?

 

[Captainoversteer]

Also worth mentioning is that the charge fuse in the engine bay now has power on it,if I pull the fuse and test both sides one side has battery voltage,which I assume is the feed and the other side has 6 volts on it.
Also on the way to work this morning the radio died and abs light came on for a few seconds,then all went back to normal,i assume this was a momentary short?
is there a 'charge relay' somewhere?

 

[Jon Wildsmith]

Not sure what your fault is but the charge fuse sits between the L (warning lamp) terminal on the alternator and the dash warning lamp. Power goes from the IGN fuse to the warning lamp (and lots of other things of course) through a blocking diode then to the CHARGE fuse and on to the alternator L terminal. So when not generating power the alternator provides a path to ground and turns the warning lamp on. When the alternator is generating power the L terminal goes positive, so power doesn't flow through the lamp and it goes off. A number of other relays and what not are also connected to the CHARGE fuse and use it to tell when the engine is running (assuming the alternator is working). Jumping power to the CHARGE fuse is just fooling the lamp and other things that the alternator is generating power.

Have you tried changing the CHARGE fuse? Maybe it is faulty.

 

[Captainoversteer]

Thanks Jon,much appreciated! Checked and then replaced all fuses to be sure first thing. I really need to buy a manual with wiring diagrams don't I!
There is no power on the charge fuse without engine running and 14.2v with the engine running,so in theory without the engine running or even with the fuse out the battery light should be on?
It is then entirely possible then,that the other night,when I had no power at that fuse with the engine running and spike it from the battery I blew the bulbs in the clockset? Wishful thinking?
Ive also come across the relay in the engine bay box marked dim has had a terminal get warm at some point and melted the holder,the wire off of it has also got warm.This wire goes up to the headlamp fuse,its not gone through and touched anything else and the pin on the relay is clean suggesting that the relay has been replaced at some point.

 

[Jon Wildsmith]

I would check if the IGN fuse has blown as that powers the warning lamp. The CHARGE fuse side is its path to 0v so removing the CHARGE fuse stops that path to 0v and the lamp won't work unless it can earth through something else connected to the CHARGE fuse which may be possible as there are several relay coils. If it wasn't p'ing down I'd go out and experiment on mine because the real world is often different to what the books say should be happening

EDIT: The wiring diagram for the charge circuit in RM184E is the same as more up to date EWD and that is on the net - www.mudtoys.com/manuals/RM184E.pdf

 

[Captainoversteer]

Thanks again Jon,I assume the IGN fuse is the third one down,RH row,on the fusebox below the steering wheel? I don't have the cover for this fusebox so have no idea which does what.
If this fuse ws blown,the engine wouldn't run?

 

[Jon Wildsmith]

engine will turn over but not won't fire with the 7.5 amp IGN fuse removed / failed. Here's a pic of the fuse cover with locations for you.

 

[Captainoversteer]

Jon,you're a gentleman,thankyou! I'm not quite so in the dark now.
I've had another quick look this morning,swopped around the relays in the drivers footwell and pulled the engine bay fusebox up to get a better look at the damaged wires/connections. I've obviously disturbed something as it is now charging until the headlights are switched on then it stops charging. Looks like the fault is something to do with where the headlight/charging circuit meet. Will study the wiring diagram some more,getting closer!?
Thanks again for your help,electrical issues are as you can tell not my strong point!

 

[Captainoversteer]

Right,so the bulbs in the clockset are good.The wiring diagram shows a charge relay,anyone know where this is and what it looks like please?

 

[Jon Wildsmith]

The charge light relay shown in the wiring diagram is only for 3F engines, that's what the *1 on the wires going to it mean, described towards the top near section 2 of the diagram.

EDIT: I'm thinking if you remove the CHARGE fuse and jump the side of the holder that is showing battery voltage with the ignition on, to 0v, the warning light should come on? Going by the wiring diagram, battery voltage will only appear on that terminal if it is via the warning lamp. If this puts the lamp on, the problem is between the CHARGE fuse holder and the alternator, or the alternator, or the alternator / engine earth. If it doesn't put the lamp on and you definitely have battery voltage there without the engine running then someone has been screwing with the wiring imo and all bets are off!

 

[Captainoversteer]

Once again Jon,a very big Thankyou.
Will see what happens

 

[Michael A S]

Hi all - can i join in?

Have been having mostly same symptoms as above and finally got to the stage of running out of ideas. Problem has been on and off for 2 weeks or so now but getting worse -
the warning lights for turbo, cam belt, sump oil, alt charge, brake warning and fuel low all come on as usual when Ign turned on (with all the others) but on engine start they stay on (others turn thelmselves off ok). At first they flashed on and off during a drive but lately have stayed on all the time with the occasional flicker.

Alt is pushing out 14.5v with no load and 14.1 with full lights and max heater on and this is the same with the warning lights or off. I checkeded all earths from Alt and batteries under bonnet and in footwells and all terminals tight. Charge and Ign fuses both OK. As with CptOversteer, there is 12v on one side of charge fuse and 6 v on other side with Ign turned on.

Any further ideas please ??

 

[Captainoversteer]

Mine's fixed!
Had to do something as I came out this morning,jumped in and it wouldnt start! No power at IGN fuse,shouted/screamed/messed about a bit,flicked ignition on and off and it came to life.
Turned out to be a combination of things but I think mainly due to a broken wire in the n/s loom. I started on the o/s(typical!) removed both battey trays,washer bottle,air box,etc. and cut open all of the engine bay loom,working my way across. As you'd expect I came across the problem in the last foot or so!
It was the power cable(thick white one) that comes from the n/s battery +ve terminal and then splits,one off to the o/s and the other in towards the bulkhead. Its tucked in against the inner wing just below the engine bay fuse box
The white cable in the pic,the two at the bottom should be joined to the one coming in from above. The green corrosion can be seen.



After repairing this joint,re-taping up the loom,checked it was all working and went for victory tea,came back and wouldnt start again/no dash warning lights,this tured out to be dodgy alarm/immobiliser thingy,have now chopped all that crap out and all's good. I dont have a fob for any alarm so it wasnt alot of use to me in the truck anyway plus Ive got a big dog/stick to chase away anyone daft enough to try and pinch my truck!

Micheal,there are numerous joints/splits in the loom like the one Ive repaired today,seems Toyota are relatively helpful in that any such jointsa have blue tape around them which makes them slightly easier to find amongst all the black tape/conduit. Good luck!

 

[Michael A S]

Thanks Dan - well done for your patience. Will start working through the looms today. I tried the old trick of staring under the bonnet for a long time yesterday hoping inspiration would come along in the form of something obvious but of course there was nothing doing.

 

[Captainoversteer]

I know that feeling Micheal,did a fair bit of that myself! Its not bad once you get going! Hope you find the problem within the first piece you look to save stripping it all out as I did

 

[Michael A S]

Fixed at last! But a good lesson learnt. The alt seemed fine - pushing out 14.5v - and batteries were good and holding up. Couldnt find any bad earths or broken wires so took truck to auto elec specialist and asked him to check it out and btw fit a new alt as I wanted a spare. New alt worked first time - and no dash lights on after start up. The old alt is off for re-furb and to have fault confirmed for the record, but diode or regulator is the suspect. Does that make sense?

 

[Captainoversteer]

Sounds about right Michael,I spent many hours reading through old threads and the alternator seems to be the trouble 90% of the time.
My truck had a new one on it when I bought itI had it of twice when trying to find my problem and checked by two different auto electricians.
Glad you got sorted!