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The mkiv Supra Owners Club

Serious electrical problem. HELP??!!!


kosmic

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I know this is a bit late, but it might save some others having problems.

 

If you ever have to jump start you car, don't connect the jump leads with your ignition on. If you want, take the key out of the ignition before connecting everything up to make extra sure nothing is turned on. Then and only then, turn the ignition on. Power spikes at the instant you connect the leads can cause all sorts of problems with the electronics.

 

This one is pretty odd as there seems to be lots of things going on at the same time. It does sound like there is mechanical movement going on because things happen going over bumps. Melted insulation does sound very possible, but it'll be a nightmare to find the problem if this is what it is.

 

Had any other work done lately?

 

I know IanC's car had some VERY odd symptoms a few years ago after the main engine earth lead worked loose.

 

Hope you find the problem.

 

Is everything ECU-like actually disconnected with the IGN off though? I wonder if the ultimate safety procedure would be to disconnect the +ve from the battery, hook the jump leads to the battery, then reconnect +ve if you see what I mean.

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as you havent touched anything electrical,just caused by jump starting,as the initial problem,I would look at the alarm especially the earth side,try disconnecting the alarm unit connector,it sounds as if it is shorted to earth,providing an earth to other car functions,horn,hazards,also these functions are usually live without ignition on,hence original jump start problem.

you could also pick one circuit ie horn,disconnect the horn earth (the line to the horn switch),replace the fuse ,if horn still on then earth problem is pre relay ,if no horn then earth is in that line,trace that wire back to problem which i suspect will go to the alarm. does that make any sense?

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Bit late now, but this is the method we use for jump starting trucks. ign on, lights on fan on, everything that can draw current switched on, then connect the leads and start engine. Theory is if there is a power surge it will go through all the lights etc and not damage anything critical. Has always worked for me.

I know this doesn't help you now, hope you get it sorted.

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what exactly did you jump it with?!!

 

My brothers Golf 1.9 TDi.

 

Just a quick update. Been out now to check the car over. Got an test meter on the batt while the car was running, a constant 14.4v. NExt carefully replaced all the fuses. Everything seems to work except the right hand side indicator lights are permanantly ON. I removed one side bulb on that side and both connections to the bulb are reading like 12v?? surely not right?! so theres a short obviously somewhere?? where do i start looking??

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looks like you still have an earth problem,start by listing the circuits that are affected and look for the common earth point,find where that is located and clean up the terminals and chassis point,also check the earth point on the alarm,and engine earth strap. if an earth point is high resistance(rusty),circuits will find an earth via another circuit connected to that earth ie feed each other- hence horn remaining on

hth

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looks like you still have an earth problem,start by listing the circuits that are affected and look for the common earth point,find where that is located and clean up the terminals and chassis point,also check the earth point on the alarm,and engine earth strap. if an earth point is high resistance(rusty),circuits will find an earth via another circuit connected to that earth ie feed each other- hence horn remaining on

hth

 

Thanks mate. I dont have any electrical diagrams to the car so i wouldnt know where to start to be honest.

 

The circuits affected are as follows:

 

CIRCUITS WHICH CONTINUELY BLOW FUSES:

Horn circuit (15A Exterior fuse)

RH Indicator Circuit (7.5A interior fuse)

PS/ABS/Slip Control Circuit (fuse 12 - 10A interior fuse)

 

CIRCUITS WHICH HAVE BLOWN BUT WORK OK NOW:

RH front main beam (15A Exterior fuse)

Stereo fuse (7.5A interior fuse)

 

Im not sure where to look to find the earth points, can anyone point me as to where to look?

 

Just a note. I changed the whole sus[ension over 2 weeks previous to this to coilovers (from RUSH' Car). to do this i ha to remove the ABS senors from the front hubs. Would damage or a short to a sensor cause all the malarky?

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Hiya :) Shall we stick to the hazard circuit as a starting point seeing as that's easily got-at in several places, i.e. the bulb holders and some bits behind the dash.

 

See attached circuit diagram, mangled due to the crazy 800*600 restriction that has popped up and I'll be having words about :)

 

All your right hand indicator circuits lead to the indicator stalk and the hazard switch. The 7.5a turn signal fuse feed most of this but the Haz/Horn fuse feeds the hazards. If you disconnect the hazard switch, the indicator stalk, and all the indicator lightbulbs (including repeaters), this will either a) clear up the problem or b) rule a big chunk of circuitry out.

 

(I'm assuming here from what you have said so far that you can use a mulletmeter, read a circuit diagram, and know the wire colour terms. Also, be aware that the circuit diagrams are a bit unclear when it comes to small numbers so maybe when I say pin 6 it's really pin 8 etc, hence me including the wire colours. I hope it's a non-facelift as the wire colours are different ;) )

 

Once you have unplugged all that stuff, make sure you have intact fuses in 7.5A TURN and 10A HAZ-HORN and fire up the electrical system. Take multimeter readings from (and post up the results here):

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y)

Indicator stalk connector pin 8 (G-Y)

Rear right indicator bulb holder (both pins)

Rear left indicator bulb holder (both pins)

 

Once you have done that, pull 7.5A TURN and meter them again. After that, pull 10A HAZ-HORN and meter them again. Post a nice table of result up here and we'll see what we get. The results will determine the next course of action :thumbs:

 

-Ian

indicators.jpg

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Hiya :) Shall we stick to the hazard circuit as a starting point seeing as that's easily got-at in several places, i.e. the bulb holders and some bits behind the dash.

 

See attached circuit diagram, mangled due to the crazy 800*600 restriction that has popped up and I'll be having words about :)

 

All your right hand indicator circuits lead to the indicator stalk and the hazard switch. The 7.5a turn signal fuse feed most of this but the Haz/Horn fuse feeds the hazards. If you disconnect the hazard switch, the indicator stalk, and all the indicator lightbulbs (including repeaters), this will either a) clear up the problem or b) rule a big chunk of circuitry out.

 

(I'm assuming here from what you have said so far that you can use a mulletmeter, read a circuit diagram, and know the wire colour terms. Also, be aware that the circuit diagrams are a bit unclear when it comes to small numbers so maybe when I say pin 6 it's really pin 8 etc, hence me including the wire colours. I hope it's a non-facelift as the wire colours are different ;) )

 

Once you have unplugged all that stuff, make sure you have intact fuses in 7.5A TURN and 10A HAZ-HORN and fire up the electrical system. Take multimeter readings from (and post up the results here):

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y)

Indicator stalk connector pin 8 (G-Y)

Rear right indicator bulb holder (both pins)

Rear left indicator bulb holder (both pins)

 

Once you have done that, pull 7.5A TURN and meter them again. After that, pull 10A HAZ-HORN and meter them again. Post a nice table of result up here and we'll see what we get. The results will determine the next course of action :thumbs:

 

-Ian

 

 

WOW :notworthy thank you Ian. Ill be having a busy weekend it seems.

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Once you have unplugged all that stuff, make sure you have intact fuses in 7.5A TURN and 10A HAZ-HORN and fire up the electrical system. Take multimeter readings from (and post up the results here):

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y)

Indicator stalk connector pin 8 (G-Y)

Rear right indicator bulb holder (both pins)

Rear left indicator bulb holder (both pins)

 

-Ian

 

Sorry to sound like a numpty. The readings at the above points, do i measure the voltage at each pin individually?? or am i measuring for resistance/continuity??

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Ok, ive been out this afternoon, testing the circuits which Ian told me and here are the readings:

 

WITH 7.5A TURN & 10A HAZ-HORN FUSES IN:

 

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y) 0v / 0.2v

Indicator stalk connector pin 8 (G-Y) 0.2v

Rear right indicator bulb holder (both pins) 0v / 0v

Rear left indicator bulb holder (both pins) 0v / 0v

 

WITH 7.5A TURN FUSE PULLED OUT:

 

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y) 0v / 0.1v

Indicator stalk connector pin 8 (G-Y) 0.0v

Rear right indicator bulb holder (both pins) 0v / 0v

Rear left indicator bulb holder (both pins) 0v / 0v

 

 

WITH 10A HAZ-HORN FUSE ALSO PULLED OUT:

 

Hazard switch multiplug pin 7 (W-R) and pin 6 (G-Y) 0v / 0.0v

Indicator stalk connector pin 8 (G-Y) 0.0v

Rear right indicator bulb holder (both pins) 0v / 0v

Rear left indicator bulb holder (both pins) 0v / 0v

 

 

Dont know if these are right or make sense.

 

I also noticed that when i replaced the 10A HAZ-HORN fuse the horns started blaring away constantly. So it seems to alternate between either the RH indicators being on permanantly or the Horn sounding permanantly. And just seems to constantly pop the power steering/ABS/Slip cont Fuse.??

 

What do i try/do next?

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hmmmm....now the RH indicators are permanantly on!! Its either them or the horn stays on constantly, seems to alternate. However when the horn is on constantly taking the fuse out stops it. When the RH indicators are on, taking the fuse out makes no difference until the ingnition is switched off. So whats the common cause here???

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cruise,Abs,steering,aerial,traction control,front spoiler and the standard toyota alarm system are all fused on the same fuse F13, so if it keeps blowing that fuse then its a possibilty that it could be alarm related, as the horn and indicators are also fed via the alarm circuit.

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Starting to make sense now. The horn and indicators are causing me major aggro as u guys know AND the ABS/power steering/traction control etc fuse keeps blowing every other time i get into the car.

 

How do i isolate the alarm system from the rest of the circuitry??

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Just read through this Sandeep. Sounds like a mare but looks like there's real progress on sorting it soon - :respekt: to all the helpers here. Good huntin' mate.

 

Thanks Ben!! Up still out there in the cold trying to sort it. Not looking to good TBH. Was really hoping i could at least isolate the problem and be at Japshow tomorrow :shrug:

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I THINK IVE FOUND THE PROBLEM :)

 

I changed my suspension to coilvers a couple o weeks ago and remeber that the front has been very low as i havent had a chance to adjust it. The right front was/has been cathing on the inner arch as i went over bumps etc in the road and burnt through the arch and into the loom just above it!! looks a right mess, il try and get pictures up later but im gonna spend the rest of this afternoon rebuilding the loom. Thank you to everyone for all your input!!

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