Broken headlight upgrade help

[FNQCairns]

Hi all, I have a GQ and bought this loom upgrade a year ago (identical just different lengths) : http://cgi.ebay.com.au/GU-PATROL-H-L...QQcmdZViewItem

No complaints whatsoever it worked just great with the higher wattage globes but just recently one of the fuses in it's waterproof holder got hot and melted (didn't blow). The inline fuse case is stuffed and that light no longer works.

Each side of the loom (each headlight) has its own body earth could this have been the cause? Any ideas welcome so I can fix it forever.

Running 120w high beam and 90w lows from memory.

thanks

fnq

[Sniper]

Can only think that maybe the earth might not have been as good of a contact as it should have been to allow for correct flow. I know that if you use a smaller earth wire than positive wire on high wattage applications you can melt wires and such. Just guessing.
Cheers
Billyboy

[Kleyny]

I'd take the earths off and clean them. Remove all paint from around the contact point. At least 10mm from the holes, sand the earth wire rings, keep the two earths and once a good connection has been sorted spray the area with some kind of rust proofing.
I would also replace the fuse holders with some good ones from someone like Jaycar.
Its a bit hard to see from the photo on ebay but the earth size looks not to bad.



neil

[FNQCairns]

Thanks fellas,

Most of the melting was to the headlight half of the fuse holder side (if that makes sense) apart from a small bit of the wire plastic covering right were it exits the fuse holder .

I am low on electric theory unless it smacks me in the face, so sorry about these Qs.
I dont understand why the fuse and fuse holder looks like it does yet the rest seems ok - could their be a weak wiring link inside this holder?
In the past for me poor earth's resulted in poor performance but not noticable overheating - why didn't this happen this time?

Is the 30amp fuse per headlight too much? 20amp better? I have had lights go out at highway speeds once and I pooped my pants, I want to feel confident I have this problem nailed.

cheers fnq

[Kleyny]

IMO 30amp is to much I'd run with 20.
Have a think about running circuit breakers instead of fuses (about 10 bucks each). They heat up break circuit then once cooled make contact again. (stop the melting problem)

Your whole problem could be as simple as poor quality fuse holders.
If your lights are going out on the highway, i would leave your lights on in the shed for 1/2 - 1hr once you do your earths and get new holders/breakers. Just to test your new circuits.

hope this helps
neil

[Amberjack]

Yes mate. It probably melted because the fuse was too high a rating. I see the ebay seller offers advice if you need it. Probably wouldn't hurt to try. Usually something like that is caused because the lights are drawing too much power, and that probably is due to a bad earth. The assumption is that the loom was of sufficient quality, in the first place.

Cheers

AJ

[chainsaw]

FNQ Cairns

If each globe is 120W then current draw for both globes is 20 Amps, 25 or 30 Amp fuses is OK. (Current draw is Watts/Volts=Amps). Problem may have been poor fuse holder, anyhow having fitted the higher wattage globes suggest fitting a 30Amp relay. Have any problems email me.

Regards Rod

[FNQCairns]

Thanks for all the good advice fella's, will go through the entire loom and earth.

cheers fnq

[gone_fishing]

sounds like a fault in the fuse holder
i wouldnt be wireing both head lights into the same circuit if one goes they all go go thats not good as you descibed
i beefed up the lights on a landcruiers by using the original wires as swith wires for relays then running heavier wire from tthe bat to relay to lights with a 25 amp fuse bit of fiddling but very effective
but melting wires is a issue of to much current for the wiring indcating bad connectin or to much draw as cheye said shouldnt draw to much so sounds like fuse holder prob

[Roughasguts]

FNQ, was it a quality fuse?
I have and will never ever use a cheap spade fuse from the 2 dollar shop again it just melted like yours and set fire to me whole wiring loome. Great fun re-wiring I gave up standing on me head gave it to a auto leccy, and it still cost 700 bucks.

I thought yeah a 20 Amp fuse is a fuse, not so I found out.

[FNQCairns]

Gut's is that possible? obviously is!! What do they use toaster element wire, something that can get hot but not separate.
Thanks for that info Gut's, the fuse came with the loom, bet it was a cheap one!!! The fuse plastic was melted and all distorted as were the metal blades (distorted) but the thin fuse bit was still intact!
Sorry to hear yours cost so much, something I will forever keep an eye on in the future, no cheap fuses!

Gone fishing, this loom has both lights a separate system so this holder should only see 120w max so around 10-11amps by the equation, the other one for the other light is fine (so far). What you say about the holder and gut's warning on the fuses both fit..... nice and tidy like!!

thanks for the advice

cheers fnq

[Roughasguts]

Hi FNQ, the reason why me short was me 12 volt cigarette lighter fell apart and earthed out, it did it 5 days before, pulling out me phone charger.
(comming home from work at 5:00 Am wasn't interested) And all I did was replace the fuse with a cheapie, didn't think any thing of it until I pulled the charger out again. And the retaining metal nut on the lighter socket fell on both Pos, and Neg terminals once the hot wire stripped it insulation and caught another earth it was over for me wiring loome.

Starting to know what was going on it took me 15 seconds, to turn the motor off and another minute to disconect the battery, but to late. The fuse should have blown there was plenty of heat there.

So there is an initial cause of the bad wiring (fuse blowing) as sugested check earths and conections.

[FNQCairns]

Thanks Gut's, rest assured I will go right through it. ATM the loom is disconnected only at the lights and am running the standard system, the upgrade loom is intact and in place.

I only know what I have seen before and I had never seen this failure where the fuse (i now suspect and it still works) should have blown but compunded in melting everything and it's plastic self instead, couldn't make heads or tails of it I think because I trusted it should have blown first.

Bit green at this stuff so just assumptions ATM.

Also I notice the place I bought the loom from has these fuses for sale at 20 for $3.40 guess that's cheap.

cheers fnq

[Roughasguts]

Yup 20 for 3.40, that be the crap fuses, come in a plastic box with lid the size of a Match box. The wire looks almost the same size for the whole Amp ranges.
If you look at them there a "S" shape with a rounded curve.

Look at the Austa brand only 5 in a blister pack, they have two really tight bends almost a figure 8 Pattern.

[FNQCairns]

Yeah cheap it is then, got me while I did not know to look .

I just got back from the engine bay multimeter in hand, I could't find a bad earth and voltage drop is low even on the longest wire's to the left headlight -something like .3 of a volt (think that is low?).

Used 2 15amp genuine nissan fuses from the demister circuits.
I checked resistance everywhere (even earth on female globe plug to another body bolt under bonnet so it had to go through the loom body earth) and voltage drop and it all seems to me to check out, is there something else I can do?

I got it wrong before, it has one fuse for high and one for low - bet that makes more sense Does anyone know how hot a fuse pumping 20amps through it should get? if at all?

How come the high beam circuit 240w = 20amp did not blow the 15 amp fuse even after 15 minutes? Battery was around 12volt.

Does it sound as if it is good to go?? and that the fuse was the problem, it was the low beam circuit that melted so a 15 amp pull?

Sorry about the extra questions, look forward to any advice.

cheers fnq