Posted: Tue Nov 01, 2016 8:46 pm Post subject: Retrofitting PSE Switch
This is something I have been wanting to sort out for some time and eventually got around to it at the weekend!
I have a topgear valvetronic exhaust that I fitted last winter, really happy with it and great quality. What I don’t like is the wireless key fob operation, the key fob is a nice metal thing, nice quality, but it’s the faffing around trying to find it when I need it and it rattling around in the little cubby shelf. I did a search to see if I could find anyone else who had retrofitted the PSE switch themselves and I found a few people who had done it in different ways, not much use but helped point me in the right direction.
The switch itself is easily available from D911 or ebay for around £60
I knew that the PSE button is not a normal switch but a momentary switch, i.e. It makes contact briefly as you push the button, but does not make a permanent circuit. This means that you need a ‘latching relay’ circuit to convert the momentary contact into a permanent on/off switch.
I found the ideal item on ebay, a momentary latching relay circuit board, this is around £6 - £8 and has various inputs plus it is a dual switch, so it can control two circuits which is ideal for this application. I am no electrical/electronic engineer but I have some limited knowledge and plenty of enthusiasm so I was sure I could make it work!!
It's the DPDT type, this basically has two switches on the relay
I tested the latching relay circuit board out with a 12v power supply, a simple button switch and an led bulb, all worked fine! However when I connected up the PSE switch to test I couldn’t get it to work! I could get the button to operate the relay but couldn’t get the LED to light up properly, so there was obviously something I was missing There are only two pins on the connector that are specific to the PSE button itself so I needed to do a little more digging. I found a circuit diagram for the switch which helped.
Testing the switch (note wiring is not correct here)
From the switch circuit I could see that the switch is on the live side and the LED needs to be switched on the earth side, after a lot of head scratching I worked it out! Luckily the latching relay circuit board has a ‘pulse’ signal input that will operate the relay, the only problem being it works on a lower voltage, between 3 and 5 volts. Thank goodness for google, all that is needed is a simple voltage divider which consists of a few resistors wired in series and a tap off between them, the size of the resistors defines the voltage you tap off. I just bought a pack of resistors from Maplin and a board to wire them up to.
All you need is two resistors in series, one half the resistance of the other, this give an output voltage at the point between the two resistors one third of the input voltage! I just used three resistors of the same value, one of them wired in series with two in parallel. The resistance of two resistors connected in parallel being half that of one!
Here is a wiring diagram i knocked up for the whole thing, quite simple!
Wiring all this up and fitting is relatively straightforward. I had fitted the receiver for the valvetronic exhaust operation next to the ECU, this is no longer needed so it’s where I fixed the voltage divider and latching relay circuit board, pic below shows it fitted and wired up. I have since removed the latching relay circuit board and put it in a small box as there is not a lot of room in his space with all the ECU wiring etc.
There are only two wires needed to run to the switch console, easy to route under the carpet to the centre console and then under the little cubby storage area to the rear of the switch unit.
Wiring up through centre console:
To remove the switch console you first need to remove the two leather side panels. The fixing are at the rear of the panel and covered by a small carpet covered panel fixed with a single torx screw. The side panels just pull out towards you. The switch console can then be pulled out, no fixings holding it in but is easier to remove if you unscrew the storage unit below it.
Once the switch is released the connector at the rear can be pulled out, there is a little tab that needs to be pressed in to release it. The actual connector is housed in a beige plastic locating cover, this is removed by cutting the zip tie at the rear and again another small tab has to be released for it to slide off.
Pic of connector:
Here is a pic of the connectors with the cover removed:
The pic below shows the rear of the connector, the two connections that need to be made are 10 an 11 in my diagram above, the two spare connections to the left of the yellow wire.
This is the fiddly bit, connecting the new wires up to the connector socket. I found some connector tails at Maplins that did the job, not exactly the right size but good enough!
The pic above shows the tails with the plastic covers removed from one end, they need to be removed from both ends. They can be slotted into the connector socket holes and when the cover is slid back on and cable tied they are held in place nicely.
Connector with cover back on:
Everything is now in place to test! Worked first time! The only thing I needed to do was swap the wires to the latching relay circuit for the solenoid and LED to suit what I wanted. Both of these terminals have a common terminal and Normally Open (NO) and Normally Closed (NC) terminals. This means you can either have the exhaust valves open or closed as a default and choose to have the LED illuminated either when the valve is open or closed.
Working
All back together and working perfectly, really pleased with it:
Rough costs for everything:
1. Switch console with PSE - £60
2. Latching relay circuit - £8
3. Resistors and circuit board - £5
4. Connector tails - £5
5. Cable - £5
Hopefully this might help anyone else who might want to do the same! _________________ Present
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Last edited by DucatiRob on Thu Feb 09, 2017 7:26 pm; edited 1 time in total
seeforez Barcelona
Joined: 10 Jan 2016 Posts: 1475 Location: up norf
Posted: Tue Nov 01, 2016 9:30 pm Post subject:
very clever rob, a lazy git like me would have just butchered a normal switch and added a LED behind the current switch but your solution is far more creative _________________ 997.1
Cheers! Really not too difficult, I'm sure someone with a bit more electronic nouse would have worked it out a lot quicker than I did! I think the good thing with this solution is that you can choose whether to have the valves open or closed as a default! Mines set open _________________ Present
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Phil 997 Le Mans
Joined: 05 Dec 2015 Posts: 15571 Location: Bournemouth,Dorset
Excellent post Rob, I was happy with my top gear key fob but now I want what you have so will be added to my 2017 mods list , really like the fact you have managed a workaround so the default can be open or closed and the same with the light. great job. _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
KJD Barcelona
Joined: 18 Feb 2015 Posts: 1253 Location: Monmouthshire
Posted: Wed Nov 02, 2016 8:19 am Post subject:
I'm amaized just how you fathom all this out
Hats off to you that's a brilliant mod IMO. _________________ Arctic Silver 997 Manual Carrera 2s
Thanks KJD, honestly it's not too difficult, I only have a very basic understanding of electrics/electronics but will have a go at anything...thank god for google _________________ Present
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Captain Lockheed Nürburgring
Joined: 19 Dec 2014 Posts: 450 Location: Bristol
Posted: Wed Nov 02, 2016 2:47 pm Post subject:
Nice job. _________________ Saving for a 993.
jpsh120 Imola
Joined: 30 Aug 2015 Posts: 750 Location: Somerset
Posted: Wed Nov 02, 2016 4:31 pm Post subject:
Hats off indeed. But as there isn't a hats off icon then
Nice job, and thanks for sharing _________________ Current: 997.2 C2S, Audi TTS mk3
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krispe Monza
Joined: 05 Feb 2014 Posts: 246 Location: Northampton
Posted: Fri Nov 04, 2016 2:02 pm Post subject:
Rob, I don't suppose you took a picture of the voltage divider and which resistors you used? Also I'm slightly confused by your wiring diagram as it looks different to how you actually wired the latching relay circuit board in the photo. (I know nothing about electronics but would like to give this a go at some point) _________________ Seal Grey 997S
Racing Yellow Cayman 981GTS
The wiring diagram is correct, the way the circuit is wired up in the earlier pics isn't right, this is when i was trying to work it out,
Unfortunately i didn't take a pic of the resistors wired up, but basically all you really need is two resistors wired up in series, the second resistor needs to be half the value of the first. This gives you a voltage between the resistors one third of the input voltage. I just used two resistors in parallel, which gives you half the resistance. I think I used 110 ohm from a multi pack i bought from Maplins.
Let me know if this makes sense, if not I can sketch it up a bit clearer. _________________ Present
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ash005 Newbie
Joined: 22 Aug 2016 Posts: 19 Location: west yorks
Posted: Mon Nov 07, 2016 11:05 am Post subject:
I was wondering, could the electronics bit of this be done on a car with factory pse to make it on or off?
cheers
jpsh120 Imola
Joined: 30 Aug 2015 Posts: 750 Location: Somerset
Posted: Mon Nov 07, 2016 12:15 pm Post subject:
ash005 wrote:
I was wondering, could the electronics bit of this be done on a car with factory pse to make it on or off?
cheers
Think you will have to explain what you mean, the factory set up already has a button that turns it on/off?? _________________ 2007 997 Carrera S - SOLD
I was wondering, could the electronics bit of this be done on a car with factory pse to make it on or off?
cheers
Think you will have to explain what you mean, the factory set up already has a button that turns it on/off??
No reason why you could not fit this in place of the PSE electronics that operate the valves from the button.
I think the benefit of this is that you can opt to have the exhaust valves permanently on or off, not sure if the standard PSE can be coded to operate in this way though! _________________ Present
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ash005 Newbie
Joined: 22 Aug 2016 Posts: 19 Location: west yorks
Posted: Mon Nov 07, 2016 11:00 pm Post subject:
DucatiRob wrote:
jpsh120 wrote:
ash005 wrote:
I was wondering, could the electronics bit of this be done on a car with factory pse to make it on or off?
cheers
Think you will have to explain what you mean, the factory set up already has a button that turns it on/off??
No reason why you could not fit this in place of the PSE electronics that operate the valves from the button.
I think the benefit of this is that you can opt to have the exhaust valves permanently on or off, not sure if the standard PSE can be coded to operate in this way though!
That's what I was wondering
As it is now, I press the button then the car opens and shuts it, I would like to have it on or off
I was wondering, could the electronics bit of this be done on a car with factory pse to make it on or off?
cheers
Think you will have to explain what you mean, the factory set up already has a button that turns it on/off??
No reason why you could not fit this in place of the PSE electronics that operate the valves from the button.
I think the benefit of this is that you can opt to have the exhaust valves permanently on or off, not sure if the standard PSE can be coded to operate in this way though!
That's what I was wondering
As it is now, I press the button then the car opens and shuts it, I would like to have it on or off
Ash .
It might be worth checking if it can be coded to do what you want, if not then this will do the trick! _________________ Present
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deMort Dijon
Joined: 21 Mar 2015 Posts: 7596 Location: Brighton
Posted: Tue Nov 08, 2016 7:19 pm Post subject:
No codeing option for it that im aware of .. sorry.
Nice job btw Rob . _________________ .
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Phil 997 Le Mans
Joined: 05 Dec 2015 Posts: 15571 Location: Bournemouth,Dorset
Rob , this sounds like a great fix for those with PSE as the cargraphic mod keeps them open but they cant be closed , the PSE does its own thing , this would give total control . _________________ 911 Owners,Some Invest In The Future,
Others Enjoy The Moment Today.
seeforez Barcelona
Joined: 10 Jan 2016 Posts: 1475 Location: up norf
Posted: Tue Nov 08, 2016 9:10 pm Post subject:
interesting, i looked into this previously and read it was a mixture of vacuums and complex electronics that you couldn't override, would be good if you could _________________ 997.1
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(I know nothing about electronics but would like to give this a go at some point)
