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Pete
Pete, Technician
Category: Australia Car
Satisfied Customers: 24656
Experience:  Over 17 years diagnosing and repairing various model vehicles with some certifications and training.
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How to trace an active short on Egnition Circuit in the 1990

Customer Question

How to trace an active short on Egnition Circuit in the 1990 Toyota Celica 2dr HB
2.2ltr, The main plus is shorting to the ground..
Submitted: 1 year ago.
Category: Australia Car
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.My info is somewhat limited on your model here but I had seen no one else has responded and would like to see if I can help here.If at any time you feel that I cannot help with this please let me know.

You want to unplug each component from the circuit the short is on then re check and see if the short is still present.If the short is still present then the short is in the wiring itself causing this issue and the wiring will need to be checked over/inspected for any damaged or shorts needing repaired to correct this here.This can be a long process tracing the wiring to locate the short but when the short is in the wiring this has to be done to locate and repair the fault.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
Hi Pete. Thank you for your respond, but I did indicate that I already had disconnected every possible device on that circuit, and it is still showing an active short indicating that the problem lies in the wiring it self and that is exactly what I need help with..!!!!
Expert:  Pete replied 1 year ago.

Can you tell me which circuit on the ignition is shorting out here as there are a few on the ignition switch side of the system?

Let me know,thanks Pete.

Customer: replied 1 year ago.
Because I have picked the wiring harness nearly completly can only say 4 sure, that it is showing active short on the Black/Red main wire coming out of Ignition it self constantly no meter of the key position and Black/Orange main wire that is going thrue the 7.5 A Ign fuse only in the key position when switched to Ign2 mark. Not sure I if that makes cents to you and if you have that car diagrams in front of you ....
Expert:  Pete replied 1 year ago.

If you remove this 7.5 amp fuse does the short still occur?

Customer: replied 1 year ago.
No !!! No !!!! No . That's how I was able to determine that the short is ectioly on that circuit. Unless I'am wrong, cos I'am not a pro If you know what I mean. Lol but based on all the research I have done it sim to pin point that due to no short acures when you pull that fuse out, that this is a troubled circuit.
Customer: replied 1 year ago.
Also not sure if that will help you, you know how when you test fo continuity with a meter it beeps giving a constant sound an showing 0.02 to 0.01 in my case it dasnt beep and numbers are not showing the reading ...
Expert:  Pete replied 1 year ago.

O.k.,this circuit feeds from the ignition switch IG2 to the 7.5 amp fuse then from this fuse to the Engine Main relay to energize this relay.This fuse doesn't feed power to any other electronics or through the relay at all as it is used to just energize the relay.If the relay is shorting internally with the coil shorting this will occur here.If there is a short from the fuse to the relay in the wire itself this will also occur.I would trace this wire from the fuse to the relay and see if any damage is found and if no damage is found then I would suspect the relay at fault here.

Thanks Pete

Customer: replied 1 year ago.
Also I did originally stated that how it initially happened it didn't burned any fuses but rather deployed a fully charged battery to 0 v.olts..
Expert:  Pete replied 1 year ago.

See the above post here and see if this helps.

Thanks Pete

Customer: replied 1 year ago.
I thought that originally so had tested the relays cos it ectioly 2 relays on that circuit 1 is Efi Main relay and 2nd Engine Main relay both tested ok, but I went furder and changed both of them, but it didn't help.
Also hav tried b4 by pulling out 1of them no Change, but when pulling both out it stops...
Customer: replied 1 year ago.
Do you have acsesss to the wiring diagram for that car-??
Expert:  Pete replied 1 year ago.

Here is the diagram of this circuit if this helps.It does show it only leading to the Engine Main Relay itself.

Expert:  Pete replied 1 year ago.

The only other issue I would see here to cause this short possibly is high resistance in the IGN 2 wiring or an issue with the wiring being shorted itself needing repaired or replaced.

Thanks Pete

Customer: replied 1 year ago.
Well I got that but ther s 2 models the 4s and 5s, mine is the 5s an I added the pic that showers exactly my set up in the main fuse box with the Efi main relay the engine main relay and another 2 more in that chan wich r the head light relay an fan control relay .. BDW I remember that b4 it hapend And the car was started last time, the fan came on as soon as I start the car but it wasn supost 2 it only comes on after the car was on like for 20 min an more, So I did find that strange at the time. If that's of any help. Sorry it just I bin Pickering at it for more than 3.5 month an it just drives me crazy, so by now I'm just so comfused wi it and had it if you know what I mean..
Expert:  Pete replied 1 year ago.

O.k.,in your diagram I do see that is powers the engine main relay,efi main relay and the radiator fan relay 1.It doesnt actually power these I guess as what it does is energizes the relay to close or open as needed.Since the fan came on from the start of this issue or when this occured have you tried to replace the fan relay 1 at all?

Customer: replied 1 year ago.
Also like I sad I hav picked that wiring harness to it core, and in the middle of the harness rite begins the ingectors under EFI I did find a main B-O wire that was just cut very vey strite and raped up wi electric tape butt did not find a 2 nd part of it no B-O wires are missing on any of the connections from the harness but mind u that this is the wire that is aperantly shorting . Rite...
Customer: replied 1 year ago.
I hav replaced all 4 relays in that circuit. No change
Expert:  Pete replied 1 year ago.

If you unplug the engine cooling fan(s) does the short go away then at all?

Customer: replied 1 year ago.
you probably correct regarding that no high power was going true it, that would provably explain why it didn't blow any fuses but just depleted the batery as a parasitic draw. If I'am rite.. Hahahaha but still doesn't help me.
Customer: replied 1 year ago.
That I can't remember ATM can check this in the morning I guess ..
Expert:  Pete replied 1 year ago.

Check with unplugging the engine fan and see if this short goes away.If it does then the fan motor is the cause needing replaced.Cooling fan failure is a common issue that may be causing this fault here.

Thanks Pete

Customer: replied 1 year ago.
If it helps you I did say it b4 one of them near the ign switch it self or should say coming out of it shows the short at all times, even if the ign switch key is off and the other 1 showes the short wen you turn the key to the Ign2 position . If that wil help you can check in the morning exactly wich 1 of them dos it when... Sorry just throwing at you all the info may b somthing wil be usefull to you....
Expert:  Pete replied 1 year ago.

When you say short are you referring to an actual short blowing fuses or shorting out a circuit or a battery drain/draw issue instead?

Customer: replied 1 year ago.
Every device every censor every electrical item or ther joining fitting has bin disconnected including the Fan connection the horn signal connection an every electrical pump is disconnected acsept all the connections going in to the Main fuse box in the engine bay the rest are off....
Expert:  Pete replied 1 year ago.

So this is an issue with the battery draining down and not an actual short damaging or shorting out a circuit am I correct?

Customer: replied 1 year ago.
Check this diagrams see if it helps
Expert:  Pete replied 1 year ago.

Try unplugging the fan motor and see if the short goes away if you can and let me know.

Thanks Pete

Customer: replied 1 year ago.
Well initially it draine fully the batery. So when started lookIng for the problem noticed that the main batery plus lead was showing continuity to the Ground.. And cos the batery main lead consisted from 2 parts hav seperated them and it was only showing short on 1 of them. So the main lead from the starter to the batery was ok but the other one going to a 100 A fuse in the main fuse box was showing short to a ground with a constant beep from the O meter....
Customer: replied 1 year ago.
Ok will check more in the morning and will go frm there.
Thanks Pete.
Expert:  Pete replied 1 year ago.

O.k.,do you have a multi meter to test with to test amperage or milliamp?

Customer: replied 1 year ago.
I have the standard multimeter tester .
And ectioly b4 I disconnected every item from the harnes conection, I had charged the batery fully up and just connected the main 2 terminals ignition off car fully off, and went to do somthing else so left the batery connected for abt half an hour and wen come back cos the bonnet was fully open I smelled an electrical short, you know That particular one the electrical burning smell and it was coming from the Alternator wich is on that 100A fuse wer I initially spotted the short in the beginning, so that means that ther is an actual short somwer on that main line and not a parasitic draw, wouldn't you agree...-? And yes the Alternator is fully unplugged ATM from both sides. And ther shouldn't be a continuity between a main (+) wire and a Ground.. Rite....
Expert:  Pete replied 1 year ago.

Yes this does sound like a short.I would try unplugging the fan when you can and see if the short then goes away and let me know.

Thanks Pete

Customer: replied 1 year ago.
To Pete.
Hi Pete. Ok I hade double checked, an the fan is unplugged in the engine bay so is evry electrical device or connection, acsept the main fuse box near the batery. Now what I hav also done is unplugged evry join connection in the main fuse box integration ( next to the batery ) To establish if A short is before A fuse box or after. And I have separated connections going into the fuse box, having on one side wires coming in to the fuse box from the in side of the car, and the 2nd lot - from the engine bay. And went true every single wire in every connection joint( that are connecting on the bottom of the main fuse box near the Battery ) and checked them for shorting to the ground. Will attach a pic diagram of it. >>2E>2D>2A<< pin #5 showing (001) all same ( no dots but constant beep ). For the reference Ground (test point 1) to the Ground (test point 2) same settings showing (001) continuity ( no dots on screen, but constant beep) wich I believe is normal. Every other wire in the rest of the joining points were clear of short( so we're the wires from the other side that I initially split ( on 2sides) 4 testing. And Ignition key in the Ign2 position wile was doing testing.
So I believe the short is in the (W) wire and not (B-O) as originally thout so.. And also that the short is b4 the fuse box, if I'am correct.
Now if I disconnect >>1H>1H>1H>1H<< plugs in on that Relay integrator, so checked it from the to any Ground in the cabin area, and it showing that short, so obviously it somewhere in the cabin area. I have an overall diagram of that Relay Integrator but not in details. So was hopping you can assist from hear on words Please. Thanks Pete.
Customer: replied 1 year ago.
Hi Pete. Ok I hade double checked, an the fan is unplugged in the engine bay so is evry electrical device or connection, acsept the main fuse box near the batery. Now what I hav also done is unplugged evry join connection in the main fuse box integration ( next to the batery ) To establish if A short is before A fuse box or after. And I have separated connections going into the fuse box, having on one side wires coming in to the fuse box from the in side of the car, and the 2nd lot - from the engine bay. And went true every single wire in every connection joint( that are connecting on the bottom of the main fuse box near the Battery ) and checked them for shorting to the ground. Will attach a pic diagram of it. >>2E>2D>2A<< pin #5 showing (001) all same ( no dots but constant beep ). For the reference Ground (test point 1) to the Ground (test point 2) same settings showing (001) continuity ( no dots on screen, but constant beep) wich I believe is normal. Every other wire in the rest of the joining points were clear of short( so we're the wires from the other side that I initially split ( on 2sides) 4 testing. And Ignition key in the Ign2 position wile was doing testing.
So I believe the short is in the (W) wire and not (B-O) as originally thout so.. And also that the short is b4 the fuse box, if I'am correct.
Now if I disconnect >>1H>1H>1H>1H<< plugs in on that Relay integrator, so checked it from the to any Ground in the cabin area, and it showing that short, so obviously it somewhere in the cabin area. I have an overall diagram of that Relay Integrator but not in details. So was hopping you can assist from hear on words Please. Thanks Pete.
Customer: replied 1 year ago.
Hello, you there -???
Customer: replied 1 year ago.
Hello.....??
Expert:  Pete replied 12 months ago.

I apologize for the delay as your question was not showing up for me until now which is very odd.Unfortunately I dont have any more info on this here myself.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

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