Switching The Pink Wire

[CharlieFarlie]

So I was thinking along the lines of drilling one of the blanks and siteing a switch there as Kingos reply says a blank can be fitted later if needed ...

I did wonder what a momentary switch was !!!

Thanks again

Wee Charlie.

I reckon if you do a photo 'how to' as you go along would win you a few friends Charlie

David. Yes this I will do as I feel this issue will raise its head many times in the future ...

Wee Charlie.

[CharlieFarlie]

Thanks for everyone's help.

Last question: is the pink wire behind the speedometer at the 5th connection point?

Please agree with it or say it's wrong.

Thanks

Mate that pink wire is behind the instruments. There is a thread somewhere that shows its location. I will try and find it..

Wee Charlie.

[CharlieFarlie]

David is this the correct resistor ???

http://www.ebay.co.uk/itm/10-x-1-0K-Ohm-0-25w-Carbon-Resistors-1-4w-Resistor-1K-/120540078313?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c10bfa0e9#ht_1446wt_1037

If so and Im reading this correctly I simply solder this inline in the wire from the switch to earth ?? Should I then heat shrink over the whole lot...... Er I think thats a self answering question but want to be sure ......

Wee Charlie.

PS anyone wanting one of the excess resistors is welcome FOC as I will never use them again !!

[Davrav]

David is this the correct resistor ???

http://www.ebay.co.uk/itm/10-x-1-0K-Ohm-0-25w-Carbon-Resistors-1-4w-Resistor-1K-/120540078313?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c10bfa0e9#ht_1446wt_1037

If so and Im reading this correctly I simply solder this inline in the wire from the switch to earth ?? Should I then heat shrink over the whole lot...... Er I think thats a self answering question but want to be sure ......

Wee Charlie.

PS anyone wanting one of the excess resistors is welcome FOC as I will never use them again !!

Them's the ones Charlie

Quite right about soldering in line and heat shrinking for insulation.

Word to the wise - don't forget to disconnect the Battery. Wouldn't want you getting a smack from an accidental airbag discharge

[CharlieFarlie]

David is this the correct resistor ???

http://www.ebay.co.uk/itm/10-x-1-0K-Ohm-0-25w-Carbon-Resistors-1-4w-Resistor-1K-/120540078313?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1c10bfa0e9#ht_1446wt_1037

If so and Im reading this correctly I simply solder this inline in the wire from the switch to earth ?? Should I then heat shrink over the whole lot...... Er I think thats a self answering question but want to be sure ......

Wee Charlie.

PS anyone wanting one of the excess resistors is welcome FOC as I will never use them again !!

Them's the ones Charlie

Quite right about soldering in line and heat shrinking for insulation.

Word to the wise - don't forget to disconnect the Battery. Wouldn't want you getting a smack from an accidental airbag discharge

Cor Blimey is that right !!!!! I think I would of disconnected it anyway but I'm glad You said !!!!!! Will anything need re setting on re connection ???

What is it that would cause that to happen ??

Wee Charlie.

[shcm]

I await incoming from SCHM

Boy, please give me strength to stop me typing something I might regret (not aimed specifically at you David, just all the stuff that's been posted).

First, I'm slightly confused as to why we have another switch diagram, when I posted one sometime ago and have linked to it more than once recently. So, I'm actually inclined to let everybody get on with it and see whether the suggested arrangement actually has the desired effect or not.

That's not in my nature, so I will tell you what I believe is wrong, but when I've actually taken the trouble previously and no notice seems to be taken and the data just get regurgitated in a different form, well, it can make you wonder why you bother can't it?

Next: "Add a 1k resistor for protection".

First, protection from what? You lot are living in the late 1970s. Automotive electronics has moved on a long way. Every vehicle manufacturer 99% of the time specifies a whole load of fault conditions every ECU input and output has to survive. That includes shorts to Battery and ground and a heap of negative and positive transient nasties. (See if you can find standard ISO7637 in all its part on the web if you don't believe me). Shorting the instrument pack (clock) input to ground is effectively what the TPMS ECU does anyway (all be it through a transistor) to turn the lamp off. It might actually make matters worse having the resistor. Ground that side of the switch input and done with it. Don't use the resistor. It may complicate things. See next. What else are you afraid of? A bit of a ground shift? It'll cope.

Second, this ones really good. The lamp is on by default and is actively turned off. This is in the interests of safety. i.e. if the control from the TPMS ECU gets disconnected from the pack the lamp comes on. This is most likely done by a pull-up resistor in the instrument pack and some voltage sensing. We already know that the threshold voltage at which the lamp comes on is at least about half Battery voltage and it may be lower.

So, you put a resistor (lets call this the pull-down) in your switch connection to ground. This forms a potential divider with the pull-up in the pack and you sit with a voltage on the TPMS lamp pack input. I don't know the value of the pack input pull-up. I've certainly seen and have specified values of around 1k for I/O pull up in the past. A 1k pull-up and a 1k pull-down will form a potential divider that gives a voltage of about half Battery.

In other words, in that situation, your switch will not turn the lamp off, but turn it on. Don't put a resistor in, just ground that side of the switch and be done with it

Now, if the pack pull-up is something like 10k, you'll get slightly less than 1V on the input. That may work (we don't know the lamp on threshold). Dropping the value of the pull-down resistor may work, but going back to my first point, I don't see the point of the resistor. The TPMS ECU output transistor when on, will leave something like 0.1V on the input. It's grounded for all practical purposes. Just ground the thing and be done with it

Hey, but what would I know about ECU design and development? Just 'cause you get paid for doing something, doesn't necessarily mean you are any good at it.

As far as the switch is concerned, when I've added ones for other purposes, I wanted something that "blended in reasonably well", but wanted to keep the switch pop-outs for when the car was sold. If you are going to drill the pop-outs fine with what you've already got.

If the pop-outs are the same size as the centre console ones, I did this (ignore the radio):

You do need to modify the console at the back, but the cut-outs go back in OK, when selling the car.

Take it or leave it.

[CharlieFarlie]

Ive bought the below for the job..

This switch as it looks neat and should be a doddle to fit..

http://www.ebay.co.uk/itm/Round-Off-rocker-switch-BLACK-SPDT-20mm-hole-snap-/370252838167?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5634c9f517#ht_619wt_1139

This one so I have a choise.

http://www.ebay.co.uk/itm/170658493339?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1640wt_1037

And these resistors

http://www.ebay.co.uk/itm/120540078313?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1446wt_1037

Which weight / grade of wire will I need ???.

I've likely got some single core stuff in the garage but just need to be sure ...

Thanks.

Wee Charlie.

Wee Charlie.

[Davrav]

Ive bought the below for the job..

This switch as it looks neat and should be a doddle to fit..

http://www.ebay.co.uk/itm/Round-Off-rocker-switch-BLACK-SPDT-20mm-hole-snap-/370252838167?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5634c9f517#ht_619wt_1139

This one so I have a choise.

http://www.ebay.co.uk/itm/170658493339?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1640wt_1037

And these resistors

http://www.ebay.co.uk/itm/120540078313?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1446wt_1037

Which weight / grade of wire will I need ???.

I've likely got some single core stuff in the garage but just need to be sure ...

Thanks.

Wee Charlie.

Wee Charlie.

See SCHM's post above Charlie - no need for the resistor - the system can look after itself without it.

Airbags going off - who knows but better safe than sorry

Gauge of wire? no idea - use the pink wire as a guide when you cut and strip it.

[CharlieFarlie]

I await incoming from SCHM

Boy, please give me strength to stop me typing something I might regret (not aimed specifically at you David, just all the stuff that's been posted).

First, I'm slightly confused as to why we have another switch diagram, when I posted one sometime ago and have linked to it more than once recently. So, I'm actually inclined to let everybody get on with it and see whether the suggested arrangement actually has the desired effect or not.

That's not in my nature, so I will tell you what I believe is wrong, but when I've actually taken the trouble previously and no notice seems to be taken and the data just get regurgitated in a different form, well, it can make you wonder why you bother can't it?

Next: "Add a 1k resistor for protection".

First, protection from what? You lot are living in the late 1970s. Automotive electronics has moved on a long way. Every vehicle manufacturer 99% of the time specifies a whole load of fault conditions every ECU input and output has to survive. That includes shorts to Battery and ground and a heap of negative and positive transient nasties. (See if you can find standard ISO7637 in all its part on the web if you don't believe me). Shorting the instrument pack (clock) input to ground is effectively what the TPMS ECU does anyway (all be it through a transistor) to turn the lamp off. It might actually make matters worse having the resistor. Ground that side of the switch input and done with it. Don't use the resistor. It may complicate things. See next. What else are you afraid of? A bit of a ground shift? It'll cope.

Second, this ones really good. The lamp is on by default and is actively turned off. This is in the interests of safety. i.e. if the control from the TPMS ECU gets disconnected from the pack the lamp comes on. This is most likely done by a pull-up resistor in the instrument pack and some voltage sensing. We already know that the threshold voltage at which the lamp comes on is at least about half Battery voltage and it may be lower.

So, you put a resistor (lets call this the pull-down) in your switch connection to ground. This forms a potential divider with the pull-up in the pack and you sit with a voltage on the TPMS lamp pack input. I don't know the value of the pack input pull-up. I've certainly seen and have specified values of around 1k for I/O pull up in the past. A 1k pull-up and a 1k pull-down will form a potential divider that gives a voltage of about half Battery.

In other words, in that situation, your switch will not turn the lamp off, but turn it on. Don't put a resistor in, just ground that side of the switch and be done with it

Now, if the pack pull-up is something like 10k, you'll get slightly less than 1V on the input. That may work (we don't know the lamp on threshold). Dropping the value of the pull-down resistor may work, but going back to my first point, I don't see the point of the resistor. The TPMS ECU output transistor when on, will leave something like 0.1V on the input. It's grounded for all practical purposes. Just ground the thing and be done with it

Hey, but what would I know about ECU design and development? Just 'cause you get paid for doing something, doesn't necessarily mean you are any good at it.

As far as the switch is concerned, when I've added ones for other purposes, I wanted something that "blended in reasonably well", but wanted to keep the switch pop-outs for when the car was sold. If you are going to drill the pop-outs fine with what you've already got.

If the pop-outs are the same size as the centre console ones, I did this (ignore the radio):

You do need to modify the console at the back, but the cut-outs go back in OK, when selling the car.

Take it or leave it.

Whilst I have the utmost respect for most if not all that You write and hugely appreciate Your opinions .... I cant understand a great deal of it !!

You are obviously very clever and definitely know Your stuff !! And therein lies the problem.. I think You fail to realise how hard it is to understand half of the above when the reader ME is so **** stupid.

Mate I have been studying Wado Ryu Karate for 43 of My 54 years I am currently an instructor at national level and would not expect a new student to understand a darn thing during the first few lessons...

I said above I felt embarrassed at asking the same questions again. I did and still do. BUT I make no further apologies for My obvious ignorance and inability to grasp the nettle...

I could have given up and simply took the car to an auto electrician. But with the help of David above I will persevere and do the job. Why ?? Well I have time on My hands and just to able to say I actually did something myself with the help of some helpful people will be My reward ... Well that and the light not flashing.

But please dont stop posting Your advice. We all appreciate it very much . Its just that some of Us are more receptive and understand Your words more than others ....

Thank You.

Wee Charlie.

[Jozsef]

Shcm!

I highly value your opinion and I'm sucking it in like a sponge.

I am a 48 year old retired border guard officer and a gardener. Electricity is so far away from here like Jerusalem to Anchorage, but I learn... From you. Thanks-

[kanulondon]

CHarlie, looks like you'll be an electrical wizz in no time! You may get a call for help soon!

[wardude]

Going on the above post and photo it seems we have the Karate Kid and Rubber Duck One in our midst

[shcm]

Charlie, as far as I am concerned you are guilty of nothing, apart from perhaps not reading carefully. The link to a thought about switching diagram was there. It's been there since January. You don't even have to search thorough the thread, I try to make the links go straight to the relevant post. Anyway, whatever.

As far as explanations go, well it would seem I'm damned if I do and damned if I don't. In this industry everything has to be justified. Besides, if I said "just do it like this" that could appear arrogant.

Going on the above post and photo it seems we have the Karate Kid and Rubber Duck One in our midst

Huh? OK, Charlie, if you can bring him down, I'll apply the electrodes at arms length. Then again, he might enjoy that kind of thing.

[wardude]

:!Removed!: in that order

Huh? OK, Charlie, if you can bring him down, I'll apply the electrodes at arms length. Then again, he might enjoy that kind of thing.