I dont believe it ....wrong fuse

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Billybob780
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Location: Hartshill North Warks

I dont believe it ....wrong fuse

Post by Billybob780 »

My fault I know.... while recovering the dash pad on my 73 Dart and while the cluster was out. I thought I would put a stereo in the glove box...... Anyway forgetting about the dangling positive cluster wire searching for ignition feed the touched metal with the associated sparks.
The car is now dead as a dodo.... I checked the fuses to find everyone was a 35 amp when two should be 3 amp and the rest 20's. Is the instrument cluster connected to the major circuits or fuse linked somewhere ?
MilesnMiles
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Re: I dont believe it ....wrong fuse

Post by MilesnMiles »

From memory the fuse box is fed from various inputs in the loom.
Have you checked whether the fusible links are burnt out in the engine bay by the bulkhead connector? I had a similar problem and nearly had a fire doing the same thing, in my case the fusible link took the damage and I rewired and replaced it with a slow burn fuse and bypassed the ammeter.
Message to both of us,always disconnect the battery when rewiring anything😬
MilesnMiles
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Re: I dont believe it ....wrong fuse

Post by MilesnMiles »

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Dave999
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Re: I dont believe it ....wrong fuse

Post by Dave999 »

miles has got it, you will have melted fusible link or done something nasty to ammeter

worst case you melted some wires, they would need to be picked out and replaced...not fun but eminently do able

disconnect battery

pull out ammeter

undo both cables

and hang them below the dash one comes from battery one comes for alternator

connect battery look for smoke and sizzling

see if you get + 12 volts on one of the cables

if so you have power from battery to ammeter which would imply power to 1 half of the fuse box when key is off and both if key is moved to run

if you have nothing at either fuseable link is gone or you melted your bulkhead connector.

if you have power



connect both cables for ammeter together with a small bolt nut and spikey washer and insulate (tape, or if doing it permanently cover in epoxy resin and tape...this would be last step if bypassing ammeter for good)

worry about ammeter function again once you have a running car.

need to see if power gets to ignition switch
(4 wires 1 is 12 volt feed 3 are 12 volt distribution to ignition, switched 12 volts side of fuse box and starter trigger wire)

if you have 12 volts on one

try switching it to run and see if it gets to ignition, 12 volts at the ballast resistor, and the switched 12 volt end of the fuse box that covers things that can only be switched on when the ignition key is in on or run.

obviously do all of this ONCE the correct fuses are in place.

if you get nowhere with fuseable link and ammeter checks
a multi meter with a continuity tester is going to be key to working out what is wrong

in lieu of this a 12 volt bulb a bulb holder for it and 2 pieces of wire or indeed a 12 volt buzzer or horn and 2 pieces of wire can be used

dave
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
Billybob780
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Joined: Sun May 16, 21 4:51 pm
Location: Hartshill North Warks

Re: I dont believe it ....wrong fuse

Post by Billybob780 »

Sorted now...... However, ahem I replaced all the dash bulbs while it was all out put it back together. Found that only the hand brake, high beam light was working no dash illumination, oil or indicators.
The cluster had to come back out when the wiper linkage came off. So the printed circuit was tested and all was ok. I had a new light switch which I fitted and now the dash illumination works but, still no oil or indicators. I'm guessing probably a faulty oil pressure switch regards that light. But, no idea on the indicators... the wing lights flash so I'm not sure what the fault is.
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Dave999
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Re: I dont believe it ....wrong fuse

Post by Dave999 »

bad earth on bulb holder.....edge of holder has a copper strap which earths to dash pod....On many cars...perhaps not all
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
Billybob780
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Location: Hartshill North Warks

Re: I dont believe it ....wrong fuse

Post by Billybob780 »

No, there nowt like that on the Dart. There's power at the oil pressure albeit the wiring has been cobbled together with a in line connector and spade connector. So I'm going for a switch fault on that. No earthing issue with the bulb holders either they were tested with the cluster out.
Billybob780
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Re: I dont believe it ....wrong fuse

Post by Billybob780 »

Well...... redone the wiring and replaced the oil switch no light on still.... and jeez the oil switch gets hot !!

Any thoughts on the indicators and oil light ?
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Dave999
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Re: I dont believe it ....wrong fuse

Post by Dave999 »

not really other than do you have the water temp and oil switch wires round the correct way?
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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Dave999
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Re: I dont believe it ....wrong fuse

Post by Dave999 »

what car is it... i.e what year of dart?

in a basic car and all of the aussie cars the dash works on 12 volts
i.e 12 volts on wires to senders including the in tank sender

USA didn't like the idea of 12 volts in the tank, what happens if it sparks, they said......! (nothing actually, no oxygen above fuel in tank it gets pushed out by the fuel vapour)). so put in a 5 volt regulator and ran the dash and fuel sender at least, just on 5 volts
the bulbs i think still run on 12 but how they did this i don't know i have not had a US car to break and fix again

if your regulator goes to cock i'd expect it just to fail BUT you never know.....

Now this is pure speculation and guess

if you were sticking 12 volts into a sender that expected 5v it might get hot.....and whatever triggers the light would be "well confused"

do you have a car with a regulator in the dash pod and is it working?

it will be a press on silver can oblong shaped or maybe phenolic black plastic and it will sit on a connector near the edge of the circuit board i would think

oil sender

when there is oil pressure the switch is off
when there is n't oil pressure the switch is on
just a spring loaded switch in a plastic capsule

power from battery or regulator through dash bulb to oil sender which is earthed by its thread. when no oil pressure switch is on so light is on provided it is being fed with power from battery or dash regulator
assuming this is a 1 wire oil sender... if it has 2 or 3 its potentially an oil gauge sender not an oil light one, and that explains well enough the issue.

the oil sender will get hot if the car is running. its in contact with hot oil, if its just getting hot instantly that would suggest it is in the on position(no oil pressure) and a large current is flowing... i.e not the low amp flow of current you get through a tiny bulb. that would indicate a mis-wire or some kind of short between your sender wire and a 12 volt source that is unrelated to the bulb in the dash

i.e power into bulb
wire from bulb ends somewhere but not the right place
different wire or short provides 12 volts into the oil sender switch and it just sinks current into the block as a dead short and hence gets hot without the assistance of hot oil up its rear end....
i'd expect a fuse somewhere to go pop or one of the other lights to be on

need the wireing diagram and a photocopier and some tippex and a marker pen

make a few copies
find the wire from the sender and follow its path all the way back to a source of power marking it along the route with a marker pen
tippex out everything that gets in the way that is not related to make it easy to look at and read with your arm halfway under the dash or in the darkness under the hood. identify each junction or connector in the car first an label them on diagram dash bulb holder bulkhead connector pin x etc etc

check 12 volts at power source 12 volts at bulb 12 volts all the way at every junction

use continuity beeper on meter to check for shorts

i.e disconnect wire from dash to sender at both ends
there should be no beep between earth and either end of wire
connect meter to both ends of wire.. (just use jump lead) you should get a beep..wire is not snapped in the middle or disconnected in the bulkhead connector

apologies if this is teaching you to suck eggs to some this comes naturally to others its voodoo... but you are just looking to see if the passage between dash and sender is clear of obstructions and diversions.

apologies bit of a ramble.


Dave
The Greater Knapweed near the Mugwort by the Buckthorn tree is dying
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