Electrical Gremlins

[ChimaeraKev]

Evening all,

I was hoping someone could shed a light on an issue I experienced today. As it has been a glorious day I thought I would make a re-start on getting my car back on the road. Today's job was supposed to be a simple one, put some coolant back into the system after draining it pre-winter for a rad change. Sounds easy enough!

So I un-cover the car as it lives outside at the in-laws and all in all looks in good nick considering the weather we've had recently! I connect the battery (pretty much brand new), lock and unlock the car for the immobiliser, turn the ignition to on and nothing. No sound of the fuel pump whirring away which I thought was rather odd. The engine will happily crank over so I don't think the immobiliser is at fault (famous last words by what I've read!).

What also seems strange is that I noticed the dash had died. The fuel gauge, clock, oil pressure showed no signs of life whatsoever. Also the fan switch seems to do nothing anymore as well. The switches for the lights work as do the lights themselves. I did check the fuses and they all seemed to be intact but couldn't properly test them as I had no spares nor a multi-meter on me (hadn't planned on doing electrical work today!). I also noticed the indicator light (only 1 on mine), battery warning and the other red light also were not lighting up.

I did however notice that when I came to check the fuel pump relays that one of them was rather wet, so I swapped them round to see if I could get the fuel pump to prime but made no difference, I can only assume that they are both knackered. I've ordered a couple of new ones to be on the safe side but does anyone have any suggestions as to why the dash might be dead?

Cheers,
Kev

[Penelope Stopit]

Could do with a diagram but, there could well be a ignition relay that supplies all the circuits you have mentioned, if the relay you found to be wet is fitted in the fuse-box there is a very good chance that the fuse box has/has had plenty of water in it and that in itself will create problems now or in the future.
First you should be checking the ignition supplies coming from the ignition switch to the fuse box and if all is good from the fuse box to the problematic circuits, should the immobiliser be playing up you are very likely going to find that fault when carrying out the above tests.
Have you by any chance left a pos or neg disconnected at the battery? Just a thought

[QBee]

Just a simple thought - could the wet have blown the 80 amp fuse in the loom near the battery? That would cause a lot of stuff not to work

[Steve_D]

QBee said:

Just a simple thought - could the wet have blown the 80 amp fuse in the loom near the battery? That would cause a lot of stuff not to work

If the 80amp is gone there would be no electrics.
I think a good clean and remove/refit on all the fuses and relays is in order as I suspect some corrosion.

Steve

[ChimaeraKev]

Yeah I was thinking of something along the same lines.

I've already ordered a box full of fuses, a new multi-meter and 2 new fuel system relays. I also want to get a new ignition relay but I forgot to take a note of the part number. Does anyone have this to hand so I can get the right one?

On another note, my wiper motor also appears to be dead. To be honest it's never worked correctly. Sometimes it would be slow, sometimes it would do 1 wipe fine then not work again. Not sure if this is related?

Cheers,
Kev

[Steve_D]

If a bit of maintenance work on the fuses and relays does not work then draw up a side by side list of things that do and things that don't work then we can look and see if anything common comes out of it be that a common power route or a common earth route.

Steve

[Loubaruch]

As Ms Stoppit said, sounds like ignition relay feeds missing. This may help:

http://www.bertram-hill.com/tvr-griffith-ignition....

[ChimpOnGas]

ChimaeraKev said:

What also seems strange is that I noticed the dash had died. The fuel gauge, clock, oil pressure showed no signs of life whatsoever. Also the fan switch seems to do nothing anymore as well. The switches for the lights work as do the lights themselves. I did check the fuses and they all seemed to be intact but couldn't properly test them as I had no spares nor a multi-meter on me (hadn't planned on doing electrical work today!). I also noticed the indicator light (only 1 on mine), battery warning and the other red light also were not lighting up.

I did however notice that when I came to check the fuel pump relays that one of them was rather wet, so I swapped them round to see if I could get the fuel pump to prime but made no difference, I can only assume that they are both knackered. I've ordered a couple of new ones to be on the safe side but does anyone have any suggestions as to why the dash might be dead?

I'd check the fuses again...



Fuse 16 is instruments, electric mirrors and boot release

Fuse 2 is the ECU

ChimaeraKev said:

I connect the battery (pretty much brand new), lock and unlock the car for the immobiliser, turn the ignition to on and nothing. No sound of the fuel pump whirring away which I thought was rather odd. The engine will happily crank over so I don't think the immobiliser is at fault (famous last words by what I've read!).

Keep in mind it's the ECU that runs the fuel pump, and the immobiliser controls ignition feed to the ECU, the immobiliser also controls the starter solenoid circuit, these are two different circuits running through the same immobiliser.

This means if the ECU immobiliser circuit is faulty you could still be able to crank the engine, it just wont start, equally you would get the exact same symptom if fuse 2 for the ECU has blown.

You are saying elements of the wiring are wet, this too has to send you back to checking the fuses, because water creates shorts and fuses are specifically designed to fail under such circumstances.

[Penelope Stopit]

ChimaeraKev said:

Yeah I was thinking of something along the same lines.

I've already ordered a box full of fuses, a new multi-meter and 2 new fuel system relays. I also want to get a new ignition relay but I forgot to take a note of the part number. Does anyone have this to hand so I can get the right one?

On another note, my wiper motor also appears to be dead. To be honest it's never worked correctly. Sometimes it would be slow, sometimes it would do 1 wipe fine then not work again. Not sure if this is related?

Cheers,
Kev

Don't start buying relays to try and cure a fault as this is the deadbeat method, all a relay does is when energised switches terminal 30 to 87, all you need do is bridge out terminals 30 and 87 to check if things power up, if things do power up you then need to check if there is a supply and return at terminals 85 and 86 of that same relay as it is those terminals that pull-in the relay contacts 30/87, if there is a supply and return at 85/86 and the relay is clicking in and sending power out through terminal 87 you will know the fault lies after the relay. See below, all tests with ignition on and relay removed
Test 1 - Link terminals 30 and 87
Does everything now power up? If yes go to test 2, if no go to test 3
Test 2 - Is there a supply and return at terminals 85 and 86? If yes the relay should power up the circuits, if no check ignition supply from ignition switch to relay and earth return from earth point to relay, find out what is missing to cause the relay to not pull-in
Test 3 - Is there a supply at terminal 30, if yes everything should power up, the fault will be after the relay, if no there is a missing power supply to terminal 30 of the relay and you will need to trace it

In summary - Once the above relay circuit supplies and return have checked out ok having been traced and rectified or have checked out ok from the first test through - The fault will be after the relay

Don't buy relays only to find you have a dodgy fuse-box or wiring

[ChimaeraKev]

Awesome advice thanks everyone!

I'm hopefully going to get chance to test a couple of bits tomorrow evening, weather permitting. What's the best method of shorting the relays? Is just a case of taking the relay out and bridging the pins on the fuse board?

Probably should have mentioned this before but my chim is a carb conversion so no need to worry about ECU related things! Hopefully that will make the diagnosis process a little easier.

Cheers,
Kev

[Penelope Stopit]

ChimaeraKev said:

Awesome advice thanks everyone!

I'm hopefully going to get chance to test a couple of bits tomorrow evening, weather permitting. What's the best method of shorting the relays? Is just a case of taking the relay out and bridging the pins on the fuse board?

Probably should have mentioned this before but my chim is a carb conversion so no need to worry about ECU related things! Hopefully that will make the diagnosis process a little easier.

Cheers,
Kev

Yes you can easily link 30 to 87 with a piece of wire that has a spade terminal on each end, if you use only the wire with no spade it is possible that a piece or two of wire could weld into the fusebox terminals or arc up the fuse-box terminals
Be very carefull that you are 100% sure that you are linking 30 and 87 at the fusebox, mirror imaging and complacency has cost people dearly, check the relay numbers/positions to the fuse-box terminal positions and mark them at the fuse-box with a felt tip pen or something before linking them, saves mistakes

[ClassicChimaera]

Penelope Stopit said:

Yes you can easily link 30 to 87 with a piece of wire that has a spade terminal on each end, if you use only the wire with no spade it is possible that a piece or two of wire could weld into the fusebox terminals or arc up the fuse-box terminals
Be very carefull that you are 100% sure that you are linking 30 and 87 at the fusebox, mirror imaging and complacency has cost people dearly, check the relay numbers/positions to the fuse-box terminal positions and mark them at the fuse-box with a felt tip pen or something before linking them, saves mistakes

Excellent advice

According the the bible ( when I read it about 5 years ago ) a number of fuse boards have been used. Check the year of your car and box fitted if that makes any difference to the wiring I don't know but thought I should point it out

[Penelope Stopit]

A multimeter wont do the job of testing the supplies at any terminal 30's
You will need a 21 Watt bulb and bulb holder with decent lengths of wire attached, meters are good but unfortunately they wont carry out a load test, see example below
I have a cable that should be providing a 12 volt power supply to a heated rear window switch that I think may be faulty, I have disconnected the switch to get to the terminal at the switch plug, I connect my multimeter between the power supply terminal in the switch plug and earth/return/body, I switch the ignition on and my meter reads 12 volts so all is well. having spent another couple of hours searching for the fault, someone suggests I use a 21 Watt bulb to test for the power supply at the switch, I connect a 21 Watt bulb to the power supply cable at the switch plug and earth/return/body and am amazed to find my bulb doesn't light up, I have found that there is no power to the switch yet my meter told me there was 12 volts there
There was a massive difference between using a meter and a 21 Watt bulb. The meter was not loading up the circuit and showed it as functioning correctly, the bulb placed just under a 2 AMPS load on the supply wire and the poor connection somewhere along the line showed up, the bulb didn't light

Multimeters often fail to show up a problem when attempting to find poor connections as they don't apply a load when using the voltage setting

[Penelope Stopit]

ClassicChimaera said:

Excellent advice

According the the bible ( when I read it about 5 years ago ) a number of fuse boards have been used. Check the year of your car and box fitted if that makes any difference to the wiring I don't know but thought I should point it out

Thank you but, going by responses to my post's, I haven't a clue what I am talking about and am a nasty piece of work
I would be carefull if I was you, you are mixing with the wrong sorts. Have a good evening

[Paulprior]

If you measure the voltage to the relay coil with the relay in place then the test with the multimeter will work, assuming the relay coil is ok and the relay earth is connected so you have a circuit, if there is no circuit made the the multimeter will measure voltage which may disappear when the circuit is complete due to a high resistance somewhere causing a volt drop, but this will only happen when you have current flowing, the bulb test is good but will not show you if you are missing the the positive or negative if it doesnt light up, but the bulb is only copying what the relay should do to the circuit but with an easy visual light up rather than a click from the relay if installed.

[Penelope Stopit]

Paulprior said:

If you measure the voltage to the relay coil with the relay in place then the test with the multimeter will work, assuming the relay coil is ok and the relay earth is connected so you have a circuit, if there is no circuit made the the multimeter will measure voltage which may disappear when the circuit is complete due to a high resistance somewhere causing a volt drop, but this will only happen when you have current flowing, the bulb test is good but will not show you if you are missing the the positive or negative if it doesnt light up, but the bulb is only copying what the relay should do to the circuit but with an easy visual light up rather than a click from the relay if installed.

No,no and no
You must have misunderstood my post or I haven't explained it well enough
When checking for a power supply at a terminal 30 relay socket with a 21 Watt bulb, you wouldn't be using any earth point at the fuse-box or where ever as the return for the 21 Watt bulb, you would use a known good earth/return point and only be checking the terminal 30 supply
In exactly the same way as when using a multimeter, a test is never performed by checking for a positive and negative as a single test
You must always use a known good negative when testing for a positive
You must always use a known good positive when testing for a negative

You shouldn't be prodding around with the relay in place as it doesn't need to be in place. If you do prod around with any sort of test gadget with the relay in place you could very easily short out 2 relay terminals and end up sending a positive to a ECU terminal or component that is sending out a negative and the resulting damage could cost a small fortune
It is very important to think hard about a test and the consequences of carrying out a incorrect method for a test in trying to save time

Edited by Penelope Stopit on Tuesday 14th March 08:57

[ClassicChimaera]

Penelope Stopit said:

Thank you but, going by responses to my post's, I haven't a clue what I am talking about and am a nasty piece of work
I would be carefull if I was you, you are mixing with the wrong sorts. Have a good evening

YHM. Read it very carefully and please don't use threatening behaviour towards me or anyone else
Thankyou.

Let's move on shall we and I welcome your support for the O/P
Let's stay focused.

Edited by ClassicChimaera on Tuesday 14th March 10:10

[Paulprior]

The point about using the bulb is good and as you say it eliminates the earth question, but i disagree with measuring with the relay in place statement, it would be quite difficult to short something out with a multimeter set to measure Voltage, especially if you use insulated needle type probes then its virtually impossible, i think both types of test have their merits, it just depends on how well you understand what you are reading, i am sure there are enough electrically skilled people on this forum to assist the O/P using a mix of methods depending on his findings.

[Penelope Stopit]

ClassicChimaera said:

Penelope Stopit said:

Thank you but, going by responses to my post's, I haven't a clue what I am talking about and am a nasty piece of work
I would be carefull if I was you, you are mixing with the wrong sorts. Have a good evening

YHM. Read it very carefully and please don't use threatening behaviour towards me or anyone else
Thankyou.

Let's move on shall we and I welcome your support for the O/P
Let's stay focused.

Edited by ClassicChimaera on Tuesday 14th March 10:10

I have needed to ask other people to read my response to your post. The reason I needed to ask other people to read my response to your post was because there was never meant to be anything threatening about it and I could not understand how you for one moment read anything threatening in my post
Having had other people read my response to your post, these people read it as it was meant to be read by anyone that posts to a public forum
My post is a tongue in cheek post and the joke in it is - I am jokingly suggesting that you should not be seen to be quoting a post of mine as Excellent advice. As you may now understand, I am jokingly mentioning that it is not a good idea for you to be seen by others to be showing anything nice in any way pointed in my direction
I jokingly posted all of this due to my manner when giving good advice being taken the wrong way. As you may understand, many people seem to struggle in accepting that there are some posters that post their thoughts and help with good intentions and at the same time knowing that some people may be offended, it is very difficult to please everyone and post honest opinions when witnessing cock-ups made by others
Not for one moment have I threatened you. Why would I wish to threaten you after you posted such a nice reply?
I appreciated your reply and then posted a tongue in cheek reply to you as a joke
I apologise that you have been offended by and read a joking post of mine as threatening
Millions of us misunderstand things posted to the internet due to there being no facial expressions to be seen and no eye contact to be made
I do hope that something good comes from this misunderstanding

I will be sending you a email using the following address [e-mail]
I am having difficulty replying to mails with my PH email address and must change it soon

Edited by Penelope Stopit on Wednesday 15th March 09:03

[ClassicChimaera]

Penelope Stopit said:

I have needed to ask other people to read my response to your post. The reason I needed to ask other people to read my response to your post was because there was never meant to be anything threatening about it and I could not understand how you for one moment read anything threatening in my post
Having had other people read my response to your post, these people read it as it was meant to be read by anyone that posts to a public forum
My post is a tongue in cheek post and the joke in it is - I am jokingly suggesting that you should not be seen to be quoting a post of mine as Excellent advice. As you may now understand, I am jokingly mentioning that it is not a good idea for you to be seen by others to be showing anything nice in any way pointed in my direction
I jokingly posted all of this due to my manner when giving good advice being taken the wrong way. As you may understand, many people seem to struggle in accepting that there are some posters that post their thoughts and help with good intentions and at the same time knowing that some people may be offended, it is very difficult to please everyone and post honest opinions when witnessing cock-ups made by others
Not for one moment have I threatened you. Why would I wish to threaten you after you posted such a nice reply?
I appreciated your reply and then posted a tongue in cheek reply to you as a joke
I apologise that you have been offended by and read a joking post of mine as threatening
Millions of us misunderstand things posted to the internet due to there being no facial expressions to be seen and no eye contact to be made
I do hope that something good comes from this misunderstanding

I will be sending you a email using the following address [e-mail]
I am having difficulty replying to mails with my PH email address and must change it soon

Edited by Penelope Stopit on Tuesday 14th March 14:02

YHM