weird electrical problem with Nissan Patrol GQ 4.2l Diesel

[Stefan]

Hi there.
I have a weird electrical problem with my '91 GQ.

I'm having major difficulties finding the problem due to the fact that it only happens sporadically.

With the ignition key in the OFF position and removed (!), some relays make clicking noises as if they engage and dis-engage. I know it's weird and doesn't make sense as with the key removed, surely all circuits should be OFF.

Lately, a new sound came on as well, which sounds like electrical sparks/number of small short circuits. This sound comes from a component where I'm not even 100% sure what it actually is. Hence the picture attached. I think it's part of the A/C but I'm really not sure.

any ideas what may cause these problems?! Pointers or contacts to good auto electrician in the Perth / Fremantle area would be greatly appreciated.

Stefan

[97_gq_lwb]

That is just your airconditioning pressure switch.
Whats that relay the little green box to the right of it doing freeballing i'd be looking at that.

[GeeCee]

What relays are switching ON / OFF - you probably need to get a location even if you do take it to an auto-elec.
Is your key / ignition barrel worn - could be removing the key before the switches are in the OFF position.

[Stefan]

That is just your airconditioning pressure switch.
Whats that relay the little green box to the right of it doing freeballing i'd be looking at that.

First of all: Thank you for the info re. ac pressure switch. Surely that isn't meant to make funny noises though if the engine isn't running, is it?
I also noticed that taking out the yellow "fusable link" which sits right on the terminal of the main battery puts an end to all the crazy clicking and switching...

The green relay is for the spotties me thinks. but will have another closer look. Yeah, sorry, some of my electrical connections are bit dodgy (some are my own fault, some from the previous owner...)

The barrel is working fine I'd say; nothing too loose there.
Did anybody else experience anything like this before? I'm just really puzzled that there are relays going with the key out and the car locked...

[Ben-e-boy]

What was the most recent electrical work done on your rig??. If there are (as you say) dodgy wiring. from yourself I would be removing and redoing the work. It makes it very difficult for people to try and help fault find when it is a rats nest of dodgy wiring. Firstly you should do a thorough visual inspection as 90% of fault are found with a visual

Cheers
Benny

[Silver]

An old trick that I first read of in a Jack Absalom book is to get a portable AM radio. Tune it off away from stations - so there is just static. Hold it near the wiring, and move the wires about.

intermittent connections etc will make sparks that the radio may pick up.

I like Ben-e-Boy's suggestion above - a bit like going back to a restore point on the computer.

I think, but am not 100% sure that there is a black plastic cylinder in the engine bay of Petrol patrols that collects fuel vapor. Mine makes the occasional noise with the engine off.

[GeeCee]

When you say yellow fuseable link, is it actually connected at the battery terminal, or under the cover next to the battery? I have similar age, but no yellow fuseable link.
What are the wire colours?
The trouble with pulling a fuesable link at the battery is that it's going to kill power to alot of things all at once, so is not so good at narrowing down the problem.
Is the relay clicking underneath the panel between the battery and guard?
How about removing fuses in the panel in the footwell one at a time.

[Yendor]

Hi Stefan,

Welcome to the forum.

Do you have an engine shut down timer fitted, condenser fan or intercooler fan fitted?

Apart from the receive drier in the photo where are the other noises coming from? inside the vehicle? under the bonnet?

Does the A/C work?

Have you been playing in mud/water holes lately and had water inside the cab?

Apart from lights, is there anything else electrical that doesn't work? or stays on when the ignition is off.

The first thing I would do is make sure there is a good earth going from the negative of the battery to the inner guard.

It appears in your photo that the negative lead has been replaced and you may not have an earth lead going to the inner guard.

The other thing that can cause a feedback like you have described is a faulty alternator. If you can get it to play up every time , try disconnection the 2 pin connector from the back of the alternator.

[Stefan]

When you say yellow fuseable link, is it actually connected at the battery terminal, or under the cover next to the battery?

That's the one: it sits under a cover right next to the positive battery terminal. 65 Amps me thinks. I'll have a look at the wire colours tomorrow. It does affect a whole range of other things (e.g. car won't start hence I constantly have to put it in before starting / while driving and take it out when parking...

Is the relay clicking underneath the panel between the battery and guard?
How about removing fuses in the panel in the footwell one at a time.

Yes, most of the clicking noises come from underneath the panel between the battery and guard where there are a whole heap of relays tucked away. It's unfortunate that I couldn't locate which of those ones actually make the noise.
I tried all fuses in the panel in the "footwell" one at a time, but to no avail.

The Aircon works, however, the switch which is meant to light up blue when ON doesn't light up anymore, and sometimes I have the feeling it's always ON, even with the switch in the "extended" [usually OFF] position.
This is also only since they worked on the aircon not too long ago...
The earth should be good, but I can double check, it looks weird on the picture I got to agree, but seems a solid connection from memory.
Spotties have been playing up lately as well, but I believe that is "only" because of the molten fuseholder I noticed when investigating. I'll get to that in a little while...
ARGH. when something's wrong it's always a few things at once, ey?

Thank you all for your input , it's really appreciated. She's been such a good girl for such a long time and even when travelling remote there was hardly anything wrong with it, but now in city life she gets cranky... (talking about the car by the way...) Maybe 417.000 kms starting to show. But then again, the engine has only just be worn in... No intercooler / supercharger btw.
Might not have lotsa time this week to investigate but will put my head under the bonnet again on the weekend, that's for sure.

[97_gq_lwb]

The aircon relay underneath the black panel is an odd thing i tapped into it to switch my thermo fan relay on and off with the aircon and had weird feedback issues it was so sensitive.

And the aircon switch blue light on mine was just a blown bulb replaced it and it now works fine quite a common thing.