Major lighting crises on my HZJ81

[Steveindar]

Hi Guys,

A recent trip to the capital city and back ended up with the last 400 km's running after dark. Strange stuff started happening to the lighting circuits. First the speedo lights all went out with only the gear indicator light and bright beam still working. At the same time the side/parking lights went dead and so did all the rear running lights and licence plate light. This lack of power affected the fog lamps too. Those of you who have travelled on the dark continent will know that making it any darker by running without sufficient light is more than scary.
Story doesn't end there though. The brights would also all of a sudden fail leaving me with absolutely no illumination. To recover this flicking the stalk to low (which would work) and then bright would get the brights to work again. Several really panicky moments but we got home with no rear lighting and prodigious low/bright flicking to keep some light going forward.
This morning everything works and is back to normal, and try as I might without waiting till dark I'm unable to replicate last nights issue.
I'm trying to make sense of the vast amount of electrical drawings, but I figure there is some clever dude here who can point me straight at whatever power source seems to be failing.
Swambo has mentioned this happening before but that was just tootling around between farms and shortish distances. I rarely drive the car so was sceptical until last night.
Is this a main relay issue, or the stalk switch? Where to look as it affects all the lighting?

 

[StarCruiser]

Look in your fuseboxes. The one under the bonnet and the one by the drivers door. Pull every fuse and relay out and look carefully for signs of burning or corrosion. With the lights on, try pulling fuses until you replicate the problem. That will almost certainly be the circuit where the problem lies. Check the relays too. There is a "dome" fuse which could be feeding the circuit at fault. Check carefully, use a torch. Also check that connectors under the bonnet are mated correctly. Uncouple them and check for corrosion and burning.

There are known relay troubles and stalk troubles but I think this is elsewhere.

 

[Steveindar]

I just came back in from trying out the lights. If I listen carefully I can hear a loose connection style noise in the footwell. I'm suspecting a relay of some sort............

 

[Steveindar]

I think this is the culprit. Nothing I can fix inside there! I'll give the connections a scrub and hope for the best.

 

[Steveindar]

Yup, must be the Headlamp Retainer relay. If I let it cool down and switch lights back on, all works but atfer a few minutes you hear another relay fall out and everything dies.
I'll touch all the solder joints with the soldering iron so long.
Tomorrow!

 

[Steveindar]

Board

View attachment 123227

 

[frank rabbets]

Why the devil do they need all those components for the headlights ? Asking for trouble and more complicated than a simple radio.

 

[StarCruiser]

Does it replicate the problem if you wiggle the plugs on that module? Or from another angle, what was your method that has lead you to suspect that module?

 

[SafariTecPeter]

Where in TZE are You located?

 

[Steveindar]

Does it replicate the problem if you wiggle the plugs on that module? Or from another angle, what was your method that has lead you to suspect that module?

Tried the wiggling with no success. Just haven't resorted to the hammer yet don't think the job is that big
With lights on if you unplug this unit all lights die including the headlights that were working plus the earlier sizzling noise I heard. Somewhere in the footwell is another relay that you can hear drops out causing the original problem.

 

[Steveindar]

Where in TZE are You located?

36L 764457.04 m E 9058828.28 m S

 

[Steveindar]

Why the devil do they need all those components for the headlights ? Asking for trouble and more complicated than a simple radio.

Toyota still have that department that invents useless stuff to amaze and confuse car owners...

 

[StarCruiser]

There's no harm resoldering the contacts on that pcb but it looks pretty good to me and is mainly resistors and transistors so nothing too complex. I'll be surprised if it is the culprit.
Stalks have been known to give trouble on older cars as have relays, mainly burned connections behind them. I think there's one in the fusebox under the bonnet which can get burned contacts in behind it. You could also swap relays like for like and see if the problem moves or goes away. That may then indicate a fault within that particular relay itself.

 

[Steveindar]

There's no harm resoldering the contacts on that pcb but it looks pretty good to me and is mainly resistors and transistors so nothing too complex. I'll be surprised if it is the culprit.
Stalks have been known to give trouble on older cars as have relays, mainly burned connections behind them. I think there's one in the fusebox under the bonnet which can get burned contacts in behind it. You could also swap relays like for like and see if the problem moves or goes away. That may then indicate a fault within that particular relay itself.

You must have read my mind, and all of the above is correct!

I soldered the board and reinstalled, all good for a minute, then lights off.
Again I hear a sizzling sound. Dig deeper in the footwell and eventually pull off the lower cowl/rocker panel plastic and find more relays.
Pulled these off and with trial and error found the one relay that controls the lights. Base burnt!
Some prodigious repairs and all good.

 

[Steveindar]

I swapped out the Horn relay for the Lights as it was in better condition and also gets used less. I'll order another.
I removed all the wires from the base, insulated them with heatshrink and pressed them back onto the relay. I have had numerous problems with spade-lug connectors, and with this one carrying so much load I feel Toyota missed the potty. Don't know what else is available that has a better connection system but I'll keep my eyes open. Having said that, they have lasted 22 years!
Seems strange that that single relay controls so much of the lighting system.
Another thing, I could not find a fuse that would isolate the power to that relay. Eventually had to disconnect BOTH batteries to isolate. Weird
So slowly one learns more about the old girl. Swambo will be pleased.

 

[Steveindar]

Brown relay also has something to do with the headlights. Probably dim and bright, I didn't check. As frank says, unnecessarily complicated.

 

[StarCruiser]

My bad, I should've said about the relays in the footwell.
The thing is to avoid corrosion as this increases resistance. Resistance = heat proportional to load which increases corrosion, increasing resistance and heat until the contacts become soft and you start getting things fail. Let's be fair here, most cars have gone to the great garage in the sky before they see 22.

Consider changing your headlights to decent LED lamps. They drop in, adjust well and give good cut off. They also halve the electrical load.

On those spade connectors, it's worth finding some replacements, even if swapping from elsewhere like the horn relay coil contact which takes almost no load for little time. As long as it's the same connector, cut it off close to the crimp and solder it to the headlight wire. Repeat with the other and you should have a brand new connector.

Caig Deoxit is an excellent contact cleaner and corrosion inhibitor.

 

[Steveindar]

My bad, I should've said about the relays in the footwell.
The thing is to avoid corrosion as this increases resistance. Resistance = heat proportional to load which increases corrosion, increasing resistance and heat until the contacts become soft and you start getting things fail. Let's be fair here, most cars have gone to the great garage in the sky before they see 22.

Consider changing your headlights to decent LED lamps. They drop in, adjust well and give good cut off. They also halve the electrical load.

On those spade connectors, it's worth finding some replacements, even if swapping from elsewhere like the horn relay coil contact which takes almost no load for little time. As long as it's the same connector, cut it off close to the crimp and solder it to the headlight wire. Repeat with the other and you should have a brand new connector.

Caig Deoxit is an excellent contact cleaner and corrosion inhibitor.

Thanks SC, I made a plan with what I have. Anything more requires planning, even getting spade lugs can be a challenge here. My next trip south I'll check for alternative lighting. Might just go for a higher amperage relay in the meantime. I would like to separate the rear lights from this circuit though.

 

[StarCruiser]

My bad again. It's easy for me to forget that things are less easy to get hold of in other parts of the world. Although I did have that thought when suggesting swapping the spade crimps.

 

[Steveindar]

No sweat, I'm glad of the input although I'm generally too impatient to wait for good advice and don't always follow it...
Tell me about your LED headlights.

S