electrics

[Dave999]

aaaaargh

etc

2 weeks ago drove car onto drive. Tacho suddenly pins itself to 7000 rpm
lights go out
interior dome light slowly dies.
turning the key does nothing. not even a click, nothing.

this collection of weirdness. makes me think its B A A A D.

i.e i already have a horrible feeling that something somewhere melted

so the car stays where it is and work starts.
Voltage at battery, voltage at fuse box 13.5
turn key
voltage at battery 13,5
voltage at fuse box 2v ???
ammeter removed
voltage at feed 13.5 unless connected to the black cable then its 2 volts
2 volts at fuse box 2 volts at ignition key switch, bloody 2 volts everywhere.

disconnect everything.
rear loom
bulkhead connectors
headlight switch
dome light
alternator feed
voltage at battery 13.5 unless connected at ammeter. then 2 volts
all connected back up
each fuse out in turn
still 2 volts

measure battery 13.5
starter relay 13.5v
red wire to ammeter 13.5v
soon as car connected 2v

short circuit? looks like it
unwrap upper and lower loom behind dash, about 15 meters of tape goes in the bin
find fat wire from alternator, junction beside bulkhead connector fat black into loom pale blue up to fuse box and ignition key black up to alternator. it runs up to ammeter and back down to fuse box. it passes itself. goes up then back down, crazy to bury that in the main loom...!
it is spliced to 4 other wires, ignition horns lights ammeter feed
looks good. nothing burnt (if you need to find the in-car splice its next to the wiper switch buried in the middle of the taped up loom)
take off ignition switch. It falls apart, firing springs and ball bearings out. bakelite internals have fallen apart. spare is pressed into service
no dice...
original is rebuilt with spare parts and reinstalled and i somehow lose the spare one.....i can't find it anywhere...weird
whole evening spent looking for it....can't find it*

so far a weeks worth of evenings spent scrabbling about in the dark swearing and cutting up my arms on under dash clips
no progress

get out of car to go in
accidentally pin the live feed to the dash with my knee. no spark.
measure 13.5 volts...odd
try to zap the dash. no spark
MMmm
charge battery
no further forward, still 2 volts when connected
all earths checked
all earths good
unwrap the loom under the hood
trace red wire
battery to starter relay all good
starter relay to bulkhead mmmm
halfway up the loom is a lump bound in 4 miles of tape
10mm spade connector. made of green dust and mush.
that'll be the problem then, wont carry current at all but voltage is 13.5 until you ask it to do something.......
new wire
new connectors
loom re taped
under dash loom retaped
new headlight light switch
new wires to tacho
new green covers in gauge cluster while i'm in here
dome light reconnected
late model connectors put on loom for ignition switch
turn key.....flat battery
charge battery
LIFE ......

2 weeks of messing and the issue was 12 inches from the battery.....

* still can't find my spare ignition lock key and switch, might have left it on the wall in the dark...but why would someone nick it....

needless to say happy but not happy... give the state of the connector i found i'm surprised i got this far...

it was an il LOOM inating experience

things i have learned
1) get a meter that measure amps as swell as volts its great to fancy transistor tester and resistance and capacitance meter but AMPS was key to this one.
2) chrysler thought nothing of using 4 offcuts of wire soldered together and taped if they could hide it from view in the bundled loom. 1 single run would have done the job. cheapskates
3) the only crusty wire in the whole interior loom was a previously disconnected dome light feed that i'd bypassed in 2004. other than that issues are caused by rubbish connectors rather than anything else 47 year old wires, shiny like new, they were all pretty good under the tape
4) aussie ignition switches are rubbish unique and rubbish and expensive and rubbish
5) if you put down a spare but weighty steering lock and ignition switch combo you will forget where you put it and it will either get nicked or be lost for a very long time, 2 hours spent looking on saturday...where is the bloody thing.

anyway, what a weight off....its now back in the garage and i will have a car working for the HRDs

miny fresh loom stupid switches and connectors

Dave

[Blue]

But you found it. Electrics are your thing.You da man. Me, I know far less and looking for unsightly lumps in the loom would come before breaking out the meter and making my head hurt....

[Bozwell]

sensitive volt meters can really throw you a curve ball.

hold the battery positive and stick the volt meter wire in your mouth, you'll easily get 12+ volts but wont be powering any bulbs.


the good old incandescent bulb test light is what I still use. (LED ones can be too sensitive as well)

[morgan]

Oh man that takes me back to when you guys were helping me chase out nastiness.
God that can get confusing quickly. You are (as blue says) da man when it comes to this stuff... well done

[Bozwell]

these things are very useful

test for bad earths (if it doesn't trip the earth is bad)

and useful for powering things up like lamps, motors etc to see if they work.

[Dave999]

Yes there were times when i thought i was going mad...but got there in the end. I'm no longer a fan off that split ribbed plastic conduit... it hides things that would be obvious contenders for complete wrong ness far too easily

ive been looking to replace my spare ignition lock and switch

all i can think of is that it is now with the scrap man...someones nicked it

spent last night looking still can't find it

ignition switch insert $200 -300 dollars

ignition key and lock $300 for one that doesn't quite fit (my standard type was used for only 6 months)

hence the type i need seems to be unobtainable. so late model only fits but looks wrong

spitting feathers i am

i must have left it on the wall or the drive in the dark last week and someone has lifted it....

i have 3 busted ones

can someone pm me TrevD's contact details... i need an intricate shape made in delrin or nylon so i can replace stupid daft bakelite parts of old broken switches...it will help me mourning my loss. i'm not paying 500+ for an unknown quantity second hand switch and loc.



Dave

[Dave999]

yes that probe looks good....

would have indicated in minutes that i could power up the car

mind so could the battery if i'd lugged it into the driver seat with me

hindsight...its a marvelous thing

[morgan]

Hey, you found a chrysler splice. I gave up trying to find mine when doing the madelectrical ammeter and just ran ignition direct but dash through bulkhead connector !

[MattH]

You are a wizard. Glad you solved it. That could have been a "put a match to it" type problem.

[Steve]

Good work Dave....you persevered and got there.

I was terrified of electrics when I got my car but, with yours and others help, I now enjoy working stuff out and learning. I have one of those probes and its great for quickly testing that the unit drawing current is working (indicators etc). Well worth having in the kit. I also have a remote starter that is a God send. Another good addition is a 6ft length of wire with a big crocodile clip on one end and a small one on the other end. Great for a quick hotwire to fault find and sometimes get you started and going again!

I have just been helping my pal fix up his 53 Packard. It had a sluggish starter motor and was a nightmare to get going. I made up really heavy leads to the starter and earths from battery to engine, engine to body and rear of engine to bulkhead. Starts perfectly now.

My Uncle is a very clever design engineer.... he has many words of wisdom and can fix anything (except my dress sense). His words stick in my mind....

"electrics are quite difficult because you cant see electricity. If you can, its already gone all wrong"

[Steve]

Don't mean to hijack the thread Dave.

When I realised I didn't have a clue about auto electrics or how to use a multimeter, I sat down with a friend who does and I took notes. Made this up, may help others...

Cheers Steve

[Dave999]

that continuity tester is the key to happy fault diagnosis in many cases.

and the resistance is handy for checking out transistors transistor is like 2 diodes back to back the resistance between middle pin and one of the others should be near 0 1 way and definitely not 0 the other both sides should match but the way round is dependent on type

a diode does the same but has 2 leads not 3

for capacitors of decent size the resistance should increase from 0 - infinite.
for little transformers you get similar. continuity test them and then use the resistance setting to power them up. if resistance increases to a point its probably ok

anything that looks like a chip. quick dab of spit on each one the one that vapourises it really fast is often the suspect one look and see if the board varnish around the pins is also burnt or been flowing into thick gloop if its in a socket swap it out and see what happens easy if the same chip is used in a few places if the fault changes you know you are on the right track.

Dave

[Bozwell]

an inferred camera is supposed to be good for looking for bad connections as it will show high resistance/hot spots even in wiring looms.

[Blue]

Spent yesterday painstakingly checking why I had no spark, everything checked out as it should. Scratching my head, I did a continuity test on the new coil lead, nothing. I removed the terminals and checked just the lead itself, still nothing, it has a break somewhere along its length, first time I've come across that one.

[Steve]

an inferred camera is supposed to be good for looking for bad connections as it will show high resistance/hot spots even in wiring looms.

What a great idea!