More Electrical Gremlins

[67cammy]

Just wondering if anyone would have an idea on where to start looking for my electrical troubles. Ever since I got the car back from the trimmer my tacho mounted on the trans tunnel and my four centre gauges have decided to only work very intermittently. When I got it back at first they were ok but soon after they stopped working. In the last six months they have sprung back into life a few times but then stop working again very soon afterward.
All the lights in the gauges and tacho work and have never stopped working.
The digital tacho on the shift light works all the time also.
Any ideas on where to start looking for something would be good. Hopefully it is something obvious because me and electricity just don't mix. :o

[blackoutsteve]

If they all stopped working at the same time, I would assume they are on a common ground. That's what I would check first. Then I would check their power supply.
Grounds are usually overlooked and often not real good.
Checking with a multimeter should be real easy.

[anychevy]

If they all stopped working at the same time, I would assume they are on a common ground. That's what I would check first. Then I would check their power supply.
Grounds are usually overlooked and often not real good.
Checking with a multimeter should be real easy.
That's what I'd look at, maybe the trimmer had to disconnect them for some reason, like to put the carpet, seats or console back in ?

[67cammy]

Thanks guys. I'll have a look and let you know. Not going in the shed now, too friggin cold

[Downesy]

As already stated check there common ground, but also if they are AutoMeter check that they have a constant 12V supply on start up or they will play up and go into fail .

[67cammy]

As already stated check there common ground, but also if they are AutoMeter check that they have a constant 12V supply on start up or they will play up and go into fail .
Yes they are all AutoMeter. Do you mean if the battery isnt fully charged? It isnt I dont think. Its a deep cycle and I have it on a trickle charger on weekends. It has gone flat a couple of times. I should have it on all the time but I need to get another extension lead (slack).

[camaro_1967rs]

Just wondering if anyone would have an idea on where to start looking for my electrical troubles. Ever since I got the car back from the trimmer my tacho mounted on the trans tunnel and my four centre gauges have decided to only work very intermittently. When I got it back at first they were ok but soon after they stopped working. In the last six months they have sprung back into life a few times but then stop working again very soon afterward.


My first check would be to check Battery voltage as suggested that it is 12vdc.
Use a multimeter to check voltage at the closest termination to the meters as possible, most multimeter probes are designed to push through wires to get a reading with their sharp ends. Doing this you can see if the 12 vdc is getting to the source, then gradually work back to the battery.
Check common earth as all the other suggestions; i.e no rust under the earthing point, or the lug used, best to put a film of copper past to create a perminant earth connection that will not rust.
Solder the ends of all crimp connectors.
Check all crip or splade connectors for strand breakage.
If you have wired to + & - in series then check the cable size from the multiple wires down to one, if this is smaller than the Autometer wires then you probably have a resistance issue and therefore a voltage drop. Make sure the negative and positive wires are greater in size to the Autometer ones.
If inline fuses are used check current rating as they may be providing voltage resistance in the fuses similar to the previous issue; if you have 4 meters at 2amp draw you need a min of 10amp fuse, this will handle the line current.
If using a relay to activate 12vdc check that someone has not connected back up wrong, or that the connector is not defective, the relay should not fail.Good luck.

I made 70% of my wiring for my car myself, and this took the first couple of months of fault finding and replacing un-used "bird nests" from under the dash, and badly burnt wiring from engine bay and boot. This is normal for our cars, and I am sure others have stories to tell.

[67cammy]

I don't think it will have anything to do with rusty connections or wiring sizes. It was rewired from scratch by someone who really knows his stuff and everything was working fine until it came back from the trimmers. I'll look for something that has physically come apart or loose that he may have disturbed and if no joy I'll try a fully charged battery. Thanks for the advice, will let you know how I go after the weekend

[camaro_1967rs]

I don't think it will have anything to do with rusty connections or wiring sizes. It was rewired from scratch by someone who really knows

Sorry i was not questioning your repairers quality, just responding to your question.

Re Corrosion of automotive fittings: this can occur to all parts once voltage applies more commonly referred to as; electrolysis. The cheaper tin type electrical fittings occurs quite quickly i.e. weeks or months, the same is also said for self tapping screws, other materials this happens to as well but at a reduced rate. I try to use stainless screws where possible, the downside here is lower conductivity vs corrosion trade-off, not enough to affect an automotive application. I am saying if here! Your trim person moved a wire, it theoretically could have been moved if corrosion has occurred to a burred part of the screw or lug, who has experienced this in a car? bad earthing due to a lug that wont conduct - or positive, hence why your curcuit may not be functioning.

Most issues occur with the earthing side as this is the side that the current travels, hence the reason why earth or ground wires corrode quicker than positive ones.

[67cammy]

Well I got the gauges to work today. All it was was a loose wire on the back of the fuse box. I can't really blame the interior guy coz it could have been me as well ( more likely ) when I was putting in the ducting for the heater/demister which runs very close to the back of the fuse box.
As always it wasn't without dramas. I was doing this in the driveway coz I don't have enough room to open the doors in the garage. I needed to go in the house so I took the lever out to isolate the battery and stupidly closed the boot. Result....no way to start the car and no way to get into the boot. The lock has been deleted and I haven't finished putting a hidden handle behind the bumper to get in there in case of a flat battery or some idiot closing the boot with the battery isolated.
Anyway I found out how easy it is to get into the boots in these things. Unscrewed the filler tube and pulled that out and pushed the rubber sleeve out the way and there was the boot lock mechanism. Just flicked it across with my finger and I was in.
Next job..finish that manual cable!