Voltage in dash lights when not on?

[mudski]

So I'm still trying to work out why the radio dims the display illumination to nigh mode when I apply the brakes. I have disconnected all the lights on the back and it still happens. One thing I did notice is the radio went into night mode when I unplugged the rhs bumper lights. It went out when I plugged it back in, but comes on again when the brake is applied. Got me stuffed. So I removed the radio facia and put my DMM onto the wire I tapped into for the night mode switch wire on the head unit. I tapped into the hazard switch....
Note : all this ONLY happens when the key is on ignition, not accessories...
So with the DMM attached, ignition on there is .8V in the wire on the hazard switch (which is for the illumination globe in the switch), I apply the brake and it rises to 1.2V, this is obviously enough to trigger the night mode on the head unit. I check the sub tank wire and its the same.
Does this sound correct? Other than just not using the night mode, I am at a loss now.

Thanks.

[mudnut]

To me, it sounds as if there is a partial leakage between the stoplight circuit and the tail light circuit. Check all of the loom to see if there is rodent damage or moisture entering from a place where the loom is rubbed through, or a fastener has pierced the insulation.

[4bye4]

Bad earth in the light cct. Probably the rear lights. If say the stop lights have a high resistance earth they will use the path of least resistance to earth which may be through the tail light cct. The bad earth fault is most commonly seen on trailers with bad earths. Strange stuff happens, like laft tail light flashes when right indicator is on and stupid stuff like that. Normally when one cct effects a different cct, its high resistance earth somewhere.

[mudski]

This only occurs when I have the ignition on though. The illumination did flicker when I plugged in the lower rh bumper loom. Its pointing toward the rear loom somewhere but why only when the ignition is on? Could I run a cable from the earth of the lights to the earth on the battery for a test? Would this work? As I said, there is low voltage in the illum wire in the dash switches when the ignition is on, with all rear light looms unplugged. Just wondering if this part is normal or not. Maybe run a test earth wire from the fuse box to the battery?
I hate this shiot! Lol.

BTW I have just replaced both earth leads on both batteries and also added one from the body to the chassis next to the sub tank, but since adding that lead my air bag light is flashing. Argh! One thing at a time please.

[mudnut]

Yeah forgot to say good earthing is essential. Doh. I could be as simple as crud in the connectors too. WD40 is your friend.

[mudski]

Yeah forgot to say good earthing is essential. Doh. I could be as simple as crud in the connectors too. WD40 is your friend.

I don't think its the tail lights. All unplugged and it still happens. It maybe be but.... Just plugging in that one lower rh loom it will make it happen. This is weird.
Edit : I'm gonna disconnect the battery and measure the earth continuity on all tail lights. Hopefully I will find something.

[threedogs]

all I can suggest is look where the loom runs along the top of the chassis
at the rear wheel arch, A few members have had problems there,
even cutting fuel lines

[mudnut]

How are the lights themselves? No moisture, all the contacts and bare copper OK? Take the globes out and try plugging it in again . Also swap the globes with the other side and try again.

[the evil twin]

Your Head Unit works correctly with the dash lights I assume?
IE dash lights 'off' day mode (cept for your problem), dash lights 'on' night mode and 12 volts on the trigger wire?

[mudski]

I tested the resistance across all earths in the back. The resistance to start at the battery to the chassis was at .4ohms. The resistance at the earths at the lights was .7ohms. I'm not expert but you'd expect this over the distance of wiring in the car?
Then I ran the DMM on the wire I used in the dash for voltage.
Heres my findings.
With RHS rear lower bumper loom plugged in....
Ign OFF : .16v with brake off, .37v with brake on
ACC : .16V with brake off, .37v with brake on
IGN on : 1.62V with brake off, 2.15V with brake on

With RHS rear Lower bumper loom UNPLUGGED
Ign OFF : .46V with brake off
ACC : .50V with brake off
IGN On : 2.28V with brake off
Brake on for test didn't change anything.

So with this loom unplugged the illumination lights on the head unit are on permanently as soon as I turn the key to ignition.This difference in voltage is only with the RH lower bumper lights. Nothing changes with the other lights unplugged.I even tried a new loom for the bumper light and no go...
I think I may have to leave this to the experts and get an auto sparky in. I'm in over my head now.

[mudski]

Your Head Unit works correctly with the dash lights I assume?
IE dash lights 'off' day mode (cept for your problem), dash lights 'on' night mode and 12 volts on the trigger wire?

Works all correct, cept the problem...12. something on the trigger wire
I've just remove the entire head unit and wiring. I'm gonna go over everything again. But I'm not exactly sure what I'm looking for. Lol. Hopefully something will pop its head out.

[mudnut]

I just measured some new 1.5mm flex cable over 4 metres and got a consistent reading of .4 ohms. If that gives you a starting point.

[the evil twin]

Works all correct, cept the problem...12. something on the trigger wire
I've just remove the entire head unit and wiring. I'm gonna go over everything again. But I'm not exactly sure what I'm looking for. Lol. Hopefully something will pop its head out.

See if there is the same issue on the 12 Volts to the ciggy plug globe or the factory Radio/CD illumination wire.

As an FYI the instrument dimmer is only powered in "Ign" via a seperate fuse to the lights off the "parker switch" which is hot off the battery (depending on models).
It shouldn't matter but may be part of the issue of the jump in teh floating voltage when the Ign is on.

[GQ TANK]

I would try a couple of 1n4004 diodes in line to the ign sense on the head unit.

The voltage drop accross the diodes should stop the issue.

Make sure that you get them the right way around, as one way they will block power, the other way they should drop around 1.8 volts = no back light issue.

This is a work around and not addressing the real reason.

[threedogs]

Nothing to do with your LED dash lights is it.
just throwing stuff out there

[mudski]

Nothing to do with your LED dash lights is it.
just throwing stuff out there

I thought about this. But the issue is when I don't have the lights on, so I ruled this out. I haven't got the facia back on my dash panel yet either as I'm still try to calibrate the fuel gauge properly. So today I'll be driving around with almost my entire dash out. lol.

[threedogs]

hope you sort it soon , you still need to do mine lol

[mudski]

I have found my issue. Luckily. My gps tracker was the culprit. All my fault too. I had the earth on the tracker not on an earth but into wire going into the head unit. Not sure exactly what wire it was now as when I found it I just plugged it all back in and started putting everything back together. The earth I was suppose to tap into was right next to the wrong wire. So I obviously clipped onto the wrong one without noticing.
Now to put it all back together and find out why the air bag light is flashing.
Im hoping its not the clock spring. Feeling it is though as I had to modify my one with a GU4 one because of the GU4 leather wheel I have. Maybe my soldering work hasnt stood the test of time...

[mudnut]

Good find, mate. So it was a bit more than a partial leakage then.

[mudski]

Good find, mate. So it was a bit more than a partial leakage then.

Yeah im not entirely sure of the hows and whys. Truthfully im not even convinced this is the issue. Im just waiting for it to go pair shaped again once I put it all back together. But using my dmm the head unit needed 1.2v to activate night mode. The same power wire now only raises to around .9v when the brake is applied.

[the evil twin]

good find Mudski... but it begs the question...
why didn't you twig when your GPS tracker was showing the JJJ playlist instead of the vehicle Lat Long?

[mudski]

Who knows mate. My head hurts, this bloody cold won't go away and its too bloody cold outside to put the car back together. A lemsip is in order and a lie down I think. I should have twigged when the stereo was trying to send me a sms to say where I am. Lol
Now for the next air bag issue. I think a sticker over the light sounds better.

[happygu]

Who knows mate. My head hurts, this bloody cold won't go away and its too bloody cold outside to put the car back together. A lemsip is in order and a lie down I think. I should have twigged when the stereo was trying to send me a sms to say where I am. Lol
Now for the next air bag issue. I think a sticker over the light sounds better.

Try this Mudski....

No guarantees as I have never tried it, but you can try to see if it can be reset by:

1) Opening the driver's side door.
2) Put the key in the ignition and turn to ON (but don't start the vehicle)
3) Within 7 seconds of turning the key to ON, push the driver's side door switch button at least 5 times.
4) The Air Bag light should go solid...give it at least 7 seconds, and it should begin to blink a 3 second, 2 second on/off pattern.
5) Turn ignition to OFF and remove key.
6) Start vehicle, and wait for the Air Bag light to turn off to verify that it worked.

This was something I had seen on the www before, and kept the info handy just in case....

Mic

[mudski]

Try this Mudski....

No guarantees as I have never tried it, but you can try to see if it can be reset by:

1) Opening the driver's side door.
2) Put the key in the ignition and turn to ON (but don't start the vehicle)
3) Within 7 seconds of turning the key to ON, push the driver's side door switch button at least 5 times.
4) The Air Bag light should go solid...give it at least 7 seconds, and it should begin to blink a 3 second, 2 second on/off pattern.
5) Turn ignition to OFF and remove key.
6) Start vehicle, and wait for the Air Bag light to turn off to verify that it worked.

This was something I had seen on the www before, and kept the info handy just in case....

Mic

Lol. Do I hop around on one leg in a counter clockwise direction and sing kumbaya?

Thanks Mic I have read on plenty of way to fix this, none worked of course, but I have never seen this one. Worth a shot though.

[mudski]

It's baaaack! Arghhh!

[mudski]

Lol. Do I hop around on one leg in a counter clockwise direction and sing kumbaya?

Thanks Mic I have read on plenty of way to fix this, none worked of course, but I have never seen this one. Worth a shot though.

Well eff me mic! That worked! Thank you! Now back to the issue at hand.

[threedogs]

now did you go clock wise or anti clockwise for the record. lol


My manual show lots of fixes like that to re-set different things
Good stuff HappyGU

[mudski]

Well I know its not the tail lights. I think. I found the box on the chassis rail with the connectors to the back. I unplugged them all and it still does it. Time to call an expert I think. Im out of ideas.

[threedogs]

Can you pull fuses one at a time to isolate it

[happygu]

Well eff me mic! That worked! Thank you! Now back to the issue at hand.

Well there you go .... something off the net and it actually works ....:first:

[mudski]

Gawd I hope I found it now. I think the resistor I used for the led brake lights has failed. I removed the led brake light globe in the rear left bumper light and it hasn't done it. Yet. Crossing my fingers.

[the evil twin]

Gawd I hope I found it now. I think the resistor I used for the led brake lights has failed. I removed the led brake light globe in the rear left bumper light and it hasn't done it. Yet. Crossing my fingers.

Why didn't you say so earlier... everyone knows about that (joking).

I have to run a load resistor in my LED brake lights to earth out the floating voltage that builds up on the brake switch when it isn't activated.
It serves no purpose when the brakes are applied but when they aren't that floater builds up to a small voltage around 2 volts or so because of the LEDs and makes my Cruise Control think that the brakes are applied ergo the CC won't engage.

[mudski]

Yeah the one on there failed, thats why I looked straight past it.
Now. I think my aux battery is fubar. Its on charge now but as soon as the sbi12 clicks off the voltage drips right off.
Im thinking I need to change the sbi12 to a dc-dc. This will keep the battery's at full charge.
My old work has a load tester. Im hoping I am able to load test the deep cycle but without a cca rating i am not sure I can. Will see tomorrow.

[mudski]

Well. I thought this issue had gone for good. It hasn't done this since the engine conversion. So I just assumed it was something to do with the engine loom causing the issue. Then yesterday, I put the left indicator on, and applied the brakes to slow down and there it is. The bloody head unit flashed in and out of night mode with the indicators. Only did it that one time, so I can't even replicate the issue.
Bloody electrical gremlins give me the shizz.

[mudnut]

Have you done any work on the wiring, recently? Have you driven the Patrol over rough roads lately?

Have you checked the same resistor and associated wiring

[Sprock]

Try disconnecting the batteries & clean the maf sensor ........ Sorry mate 😂

[mudski]

Have you done any work on the wiring, recently? Have you driven the Patrol over rough roads lately?

Have you checked the same resistor and associated wiring
The only wiring i have done is for the new twin compressor, but that was pretty much just a remove and refit the new wiring in the centre console. And no resistors at all now. I removed all LED globes.

Try disconnecting the batteries & clean the maf sensor ........ Sorry mate 😂

Oh sh!t, he's alive! And STFU!. ;)

[dom14]

Well. I thought this issue had gone for good. It hasn't done this since the engine conversion. So I just assumed it was something to do with the engine loom causing the issue. Then yesterday, I put the left indicator on, and applied the brakes to slow down and there it is. The bloody head unit flashed in and out of night mode with the indicators. Only did it that one time, so I can't even replicate the issue.
Bloody electrical gremlins give me the shizz.

Tell me about it mate! ;)
I've dealt with my fair share of these electrical gremlins that pops out of nowhere.
Few years ago I used to run into the auto sparky and cry.
These days, i take it as a challenge and a hobby(Thanx to this forum)
Sure thing, you ain't got no time to muck around while running a business, hey it's still a
good hobby! :D
These electrical gremlins can cause experienced auto sparkies to scratch the back of their head.
It's never easy.
Fortunately for me, I'm perverted enough to think it's fun. ;) :D

[4bye4]

Almost certainly a missing earth or a high resistance earth. With the brake and indicator on there was no good earth return so it found a path through the head unit. Since you can't replicate it it is probably a lose earth connection either on the brakes or the indicator circuit, probably the indicator as the head flashed in time.

[mudski]

Yeah thanks. This issue has got me stuffed. Both left and right now do it. I'm wondering if it just the cheap Eonon head unit. Or if I find the earth wire on the flasher can and/ or the brake light switch, and run a wire directly to the -ive on the battery to see if this helps. Its just strange how it disappeared for 12 months, now its back.

[dom14]

Yeah the one on there failed, thats why I looked straight past it.
Now. I think my aux battery is fubar. Its on charge now but as soon as the sbi12 clicks off the voltage drips right off.
Im thinking I need to change the sbi12 to a dc-dc. This will keep the battery's at full charge.
My old work has a load tester. Im hoping I am able to load test the deep cycle but without a cca rating i am not sure I can. Will see tomorrow.

Fleabay sells battery analyzers relatively cheap these days.

http://www.ebay.com.au/itm/FOXWELL-BT100-12V-Car-Battery-Analyzer-Tester-f-Flooded-AGM-GEL-Battery-System-/282064969526?hash=item41ac61df36:g:u~4AAOSwOVpXW7H L
http://www.ebay.com.au/itm/2016-12V-Aumotive-Vehicle-Battery-Tester-Car-Battery-Analyzer-Digital-Display-AU-/252532062425?hash=item3acc1578d9:g:9AoAAOSwAYtWGe9 E

I had a one but lost it, otherwise I would've given it to you. The most useful reading of an aux battery is AH, but afaik, there's no quick way of getting an accurate reading on that(other than doing a proper test with a fixed amp drawing load), but CCA reading is definitely doable with a one like the above. Considering a battery load tester costs around $30 or more, above price for a battery analyzer is pretty good. I have a load tester, but switch got cooked. I have to replace it, & I'm hoping to fix it next couple of days.(need a high amp capable switch).

You can also take your battery to a battery shop or autobarn, etc. They have more expensive(and more accurate) testers and usually test the battery for nothing. I think the best way to test the battery is when it's open circuit. Readings you get from fitted batteries aren't reliable IMO.

[dom14]

Yeah thanks. This issue has got me stuffed. Both left and right now do it. I'm wondering if it just the cheap Eonon head unit. Or if I find the earth wire on the flasher can and/ or the brake light switch, and run a wire directly to the -ive on the battery to see if this helps. Its just strange how it disappeared for 12 months, now its back.

Sounds like weak connection/earthing issue, doesn't it?

[mudski]

Sounds like weak connection/earthing issue, doesn't it?

Yeah it does. But where is the question.

[mudski]

Fleabay sells battery analyzers relatively cheap these days.

http://www.ebay.com.au/itm/FOXWELL-BT100-12V-Car-Battery-Analyzer-Tester-f-Flooded-AGM-GEL-Battery-System-/282064969526?hash=item41ac61df36:g:u~4AAOSwOVpXW7H L
http://www.ebay.com.au/itm/2016-12V-Aumotive-Vehicle-Battery-Tester-Car-Battery-Analyzer-Digital-Display-AU-/252532062425?hash=item3acc1578d9:g:9AoAAOSwAYtWGe9 E

I had a one but lost it, otherwise I would've given it to you. The most useful reading of an aux battery is AH, but afaik, there's no quick way of getting an accurate reading on that(other than doing a proper test with a fixed amp drawing load), but CCA reading is definitely doable with a one like the above. Considering a battery load tester costs around $30 or more, above price for a battery analyzer is pretty good. I have a load tester, but switch got cooked. I have to replace it, & I'm hoping to fix it next couple of days.(need a high amp capable switch).

You can also take your battery to a battery shop or autobarn, etc. They have more expensive(and more accurate) testers and usually test the battery for nothing. I think the best way to test the battery is when it's open circuit. Readings you get from fitted batteries aren't reliable IMO.

Thats an old post Dom. A lot has changed since that post.

[dom14]

Yeah it does. But where is the question.

I can only feel your pain, mate. I've been there. Auto sparky won't do it 'cos they can't charge you for the time.
Probably the most economical thing to do is to rewire the damn thing.
I had to do that in my case, with my dramas with fuel pump electrics. A real PITA to locate the exact spot of weakness, so
I rewired it, and fuel priming is done manually with press button now( I didn't even bother to replace Fuel Pump Control Unit).
I've been on the mission to add extra earth connections to the chassis & body. Time well spent, I think.

[mudski]

Fark that! I'll just put up with it rather that rewire the car. I'll find the issue one day. Maybe.

[dom14]

Fark that! I'll just put up with it rather that rewire the car. I'll find the issue one day. Maybe.

Yeah, one day when your girls start bringing in grand kids to see ya. ;) :clapping:
In my case, I had to 'cos it's critical if I'm to drive on petrol reliably.
I did the same thing(almost) with all the LPG electrical wiring, but mostly 'cos the wiring was done badly in the
first place. It was more like a backyard LPG conversion(electrically).