ALMOST burned up my wiring harness

[bighealeysource]

Hey all,
Despite reading about and being very careful to have the
license plate light grounded properly, when I went to hook
it back up ( after a repaint with all rear lights out)
I hooked the red light wire back up to the stop light pig tail.
Fortunately kept my fingers on it and it got hot almost
at once. Disconnected as did not want to be another one to
burn up his harness. Well, despite disconnecting it in just
a few seconds, I have had a partial meltdown of the red wires
from the headlight switch, to the fuse box, and in the main
harness going to the front head lights. Checked them and
the wiring there appears okay and oddly enough, fine at the
rear end. But up front, I managed to melt down the insulation
on some of it. All the other wires and insulation appear to
be okay, just the red got hot and started to melt down. My
question is can I simply "graft in, so to speak" new wiring
to replace that with the damaged insulation ? this is the
original harness on a BJ8 and was not planning on replacing it
as other than the above bonehead move by yours truly, was in
great shape. I will obviously have to cut into some of the
fabric wrap to check on the red lines but seems like I can
replace the portion that got too hot. Advice, consolation,
recommendations for something strong to drink ????
Thanks,
Mike

 

[Keoke]

Hi yes if you can locate all the failed wiring you can replace it with new. Sorry you have the problem. But You should have had a 2 -to- 5 AMP in line fuse connected to the main red power wire and located in the boot. - Everyone else has this fuse installed right??---Keoke-

 

[GregW]

Hi Mike,
When I was in Hawaii a while back, I was introduced to something called a "Purple Haze". It's hot Sake and Chambord, ummmmm. About 60% Sake, add the Chambord after heating the Sake. Other than that, sounds like you're on the right track. It is possible you've fried your light switch, so you may want to check that before running juice through it again.

P.S. Did you figure out the source of the short? Plugging the red wires together shouldn't have resulted in smoke letting.

 

[Patrick67BJ8]

My experiences with the harness on my BJ8 was similar to yours.
I removed it from the car and laid it on a piece of plywood supported by a couple of saw horses. I used an xacto knife and opend up the harness right down the middle of it. There was two RED wires(memory here), that were cooked in one spot and distincly warmed alll the way from one end to the other. I used nails to keep everything in some sort of alignment and then I carefully removed the burnt wires and replaced them with new ones. After that was done it, the harness was off to Rhode Island Wiring Service where the orginal braiding was redone.
No problems with it since!
Don't want to spend the money on braiding (?), wrap it with black electrical tape. I will be inspecting the harness again now that my car is completely stripped down to the bare frame(and presently at Jule-Enterprises), before installing again.
Patrick

 

[Healey 100]

Burning up the wiring harness is very easy to do when restoring any car, all you need is one connection shorted or miswired. It is even sadder when the shorts fry a brand new and very expensive harness.

I use the following trick when repowering a car under restoration: hook up the harness first to a small battery charger (10A or less) and test all the circuits you can. If there are any shorts, the current limiter on the charger will keep the current low enough to prevent damage. My charger emits an audible click when the current limiter goes off, makes it easy to find shorts.

 

[tahoe healey]

You may want to consider the black wire wrap used to make computer wires look organised. It is a flex plastic that has a slit running down the length and can be zip-tied. Easier than electric tape and can be accesed at any part of its lenght if needed.

 

[Ed_K]

If you chose to use black electrical tape. I would suggest the rubberized cloth friction tape instead of the all common plastic electrical tape. If you replace a bad section of red wire, I would suggest that the connections be soldered and then wrapped with the friction tape. You can either use the friction tape or the black plastic tubing mentioned by T.H. to protect/enclose the cable.....
I think you now understand the need for more fuses than what the factory provided !
Put a 2 amp inline fuse holder in the red wire right before it exits through the hole out to the license plate light. Also put another 10 amp fuse in the RED wire right after it leaves the light switch. That will protect all of the red wires to the four marker lights as well as the license plate along with the dash lights. If your red wire got hot that goes out to the license plate light, then it is shorted to ground. It is common for that wire to short out against the inside of the hole. Check for a worn out or missing rubber grommet in the hole or a short inside of the light assembly.

 

[RonMacPherson]

Your friendly local Napa store also sells a cloth braid wrapping tubing. If the counter guys gives you the deer in the headlights look when you ask about it, have him look in the truck section of the electrical catalog.

 

[andybj8]

While you are at it, I would check to see if your fuses are british spec or american. If you have replaced the standard fitted Healey 35a or 50a with a local sourced from walmart (or wherever you americans buy fuses from) its asking for trouble.

Original lucas fuses that are rated at 35a (will be rated 17a continuous and 35a trip / blow. Therefore if you have replaced it with an american fuse that says 35a made by bussmann (or whoever, they will be marked AGC as a standard for US) it is rated at 35a continuous and 60a blow. Much more than the prince of darkness intended. Hence frazzaled loom letting out smoke.

Any other circuits or fuses you add will be fine if you work out the load and rate using your standard american fuses.

Just make sure the standard 2 healey fuses are either 50a british / 25a US and 35a british / 20a US.

Just do not mix the two rating standards up.

ps British fuses tend to be marked IEC.

cheers Andy

 

[Keoke]

Hi Andy, you are correct about the fuse ratings. However, when this type failure occurs the standard fuse is located too far away . Consequently, the wiring harness protects the fuse while it also destroys itself. --Keoke

 

[andybj8]

Keoke, quite agree , just pointing out the difference, and one correct rated fuse is better than none.

Incidently i would personally fuse the red at the switch, then it covers all side lights and number plate.Most people add the fuse as the bj8 diagram (after the split connection in the trunk so it only covers the plate)

I am trying to keep my bj8 standard to look at,so it is hard to fuse all the seperate circuits from the fusebox, hence I have just bought a 4 way lucas 7fj fusebox(period) to fuse easy to get at circuits (from the switches) and will locate it under the heater. The 4 easy ones (negative earth) will be the blower, panels lights, side lights, and headlights). I will add an inline fuse for the od and have the standard bj8 boot/trunk fuse as well. You could go the whole hog if you dont want to keep it standard and split the lights / add relays etc...

I would like to do the other circuits such as the indicators but it would be hard not to see the wiring mods as you need to split the greens or put an inline from on the relay green.

Again my view is any correctly rated fuse helps.

And before any one chimes in about having lights on one cct, which is better a burnt out car, or trying to figure why you have no lights standing by your car in the dark?

cheers Andy

 

[bighealeysource]

Hey y'all,
Been out of town for the last week and did not have access to e-mail. Thanks
for all the advice and info on my harness problem. I will definitely add the
in line fuse and look to replace the damaged red wiring. Going to check out
that cloth braided wrapping at NAPA that Ron mentioned. One more question on
this subject - would it make sense that only sections of the red wiring were
damaged since my first attempts to see where and how much damage was done
seem to indicate that some sections of the red wiring were not damaged at all ?
Thanks,
Mike

 

[GregW]

Hi Mike,
Before you pull too much apart, I'd look for the source of the short. You can disconnect the red wire in the trunk from the harness and check the lic. plate and two running lights with an ohm meter. If that is OK, then move on to other parts of the car. One question, when you plugged the wire in before it fried, was the light switch on the dash on?

 

[bighealeysource]

Hey Greg,
Unfortunately my BJ8 has had what looks like a lot of messing around with the
wiring in the trunk. Some wiring has been added in and I have a section of the
infamous red wire where an additional red wire was spliced into the harness
and that is probably where my problem exists. My lights all work fine and I
probably had the light switch "on" when I ran into my problem. Of course do
not know right now if the lights or the switch works ! I am going to go back
to the basics and try to determine why that extra red wire was spliced in.
Thanks,
Mike

 

[Keoke]

Andy! don't get gaught ona back road ina dark standing beside your car carry a big "Torch".---Keoke--