4C Suspension repeater telltale lights
 

One small area of dissatisfaction with my 2012 XC70 is the placing of the 4C suspension selection buttons. While moving all three buttons would pose a difficult problem, I realised that what I find the most irksome is having to look down at the base of the central console to try and see which suspension setting is selected. This means taking my eyes off the road and squinting to see the tiny lights which are hard to make out on a bright day if I'm wearing sun glasses. So that's the problem.

The solution might well be leaving the buttons where they are and installing three warning lamps on the edge of the plastic ledge under the dials behind the steering wheel. I've painted them in on the picture.

What I would need is advice on the selection of the lamps and the pick-a-back wiring from the buttons to the repeaters.

The final effect would be that I could see which suspension setting was selected by looking at the dashboard and not down into the car. Do not understand why Volvo didn't integrate these indicator lamps into the dash in the first place.

Can anyone with intimate knowledge of the wiring on the XC70 suggest what lamps I need to provision and how the wiring should be configured.

I find it easy to see due to the LED's being coloured. I just leave it in Sport with only the odd comfort setting when the roads are really crap but overall Sport works better even when roads are iffy.

And I leave it in Advanced for most of the time but that isn't the issue.

If I am entering an unmade road, and there are plenty of those in Dorset, or a road with speed bumps, and there are plenty of those in Dorset!, I switch to Comfort to avoid harsh shocks to the car. If I am of a mind to do so, I'll revert to Advanced when re-entering a smooth black top road, perhaps not so many of those in Dorset! The problem I am encountering is that if I forget to revert, I would need to look down at the poorly placed control buttons just to see their indicator lights and check what suspension setting was selected and that would mean taking my eyes off the road when dash mounted lamps would draw my attention to the setting without any conscious thought on my part. I am constantly aware of poor ergonomic design in instrumentation in vehicles where the designer was sitting at a computer and when the design was put in the car he wasn't actually driving it! Volvo are not the only offenders by any means.

I am looking for advice on how to make this modification, not less-than-helpful advice on what other driver might or might not consider the merits of having the modification. It's a technical assistance query not a discussion on what some other members might or might not like about the feature which I would like to install. Information on wiring and the choice of lamps is what I need, not advice on how to drive my car. No offence meant but a debate on how we all drive is going to clog up the thread and deprive me of any opportunity to gather useful information. Thank you. :regular_smile:

The "lamps" in the Switch are LEDs.
You will need to open up the switch and run wires from the switches LEDs to other LEDs placed where you want them to be.

Either the switch LEDs and the external LEDs in series, and modify the series resistor slightly to adapt for the extra voltage drop.
Or in parallel with your own current limiting resistors.
As LEDs use f-all power, there will be no issues with extra "load"

Electronic and Soldering skills required.

Am I right that LEDs have a polarity issue? Is there a way of knowing which way around the repeaters should be connected or is there no harm done if the random choice gets it wrong and than they are reversed?

"Either the switch LEDs and the external LEDs in series, and modify the series resistor slightly to adapt for the extra voltage drop.
Or in parallel with your own current limiting resistors."

The series resistor; is that something that's there already and how will I recognise it? In what way should this resistor be changed? What is the extra resistance it needs to provide? What are the implications of wiring in series or parallel and if in parallel should my resistors be duplicates of the ones already there?.. If in each of the three swithes I attach the repeater LED wires to the wires coming out of the main LEDs, where do I put the resistor? Sorry to be dense but once I have an idea of what needs doing and know that it's not likely to cause damage, I'll probably seek practical help on the day.

I'm OK with soldering but it's knowing what is to be soldered that scares the bejabers out of me!

Firstly: the nature of your questions make it clear that you may be taking on more than you can chew.

LEDs have no issue whatsoever with polarity.
They have a requirement to be connected with the correct polarity, but it is not an "issue".

I suggest studying basic electronics 101 and learning about voltage, current, power, and how much voltage and current an LED consumes, and why current limiting resistors are necessary.

Start with Wikipedia
https://en.wikipedia.org/wiki/LED_circuit

Firstly: I absolutely agree with you. Which is why I was asking if anyone could help me with a "how to" rather than an electronics lesson.

If you prefer the word requirement, that's OK with me. I was merely expressing a belief that it may matter which way round you connected an LED into a circuit and you have confirmed that it does.

I didn't really want to take a basic course in electronics if someone could say that for each switch I should connect the + pin of the LED to this connection, the - pin to this other one and insert a resistor of a given value between one of the two new connections. I'd hoped that the additional wiring would not be complicated but if you feel that there are too many pitfalls for someone without electronics training and that simple 'do this/do that' instructions cannot be given, I will need to use an auto electrician to assist me. Thanks for taking the time to consider my requirement. :regular_smile:

The signals to the LEDs pass 74/503, which is a 22-pin gray connector at the tunnel console.
The current limiting resistors are built-in inside the Four-C switch unit, so if you just connect the LEDs in to poles 18, 19 and 20, smoke will emit. There's also one additional forward voltage drop inside the switch unit, before returning to pole 16.
Pole 17 connects all three switches, pole 15 another LED, which I presume is the symbol lighting in the switch unit.

The previous generation of V70 had these switches more visible, but the general dashboard design in this generation doesn't allow for that.

A step forward but when you say that a simple connection to the 18, 91 & 20 poles will cause overheating is this with the repeater LEDs or in the switch? If it is the repeaters, would 3 suitable resistors between the three poles and the repeater lines eliminate that problem? If so, any idea what would be a suitable resistor value. If the overheating problem is generated in the switch unit, would the resistors in the repeater lines eliminate that or is the installation a whole lot more complicated? Secondly, when you refer to these three poles, are they pairs or do the returns have to go somewhere else specific?

Sorry to labour these points but I'm trying to construct a "How To" for myself from the advice given so that I can buy the correct components, identify the correct connection points and reduce the job to a simple soldering and assembly procedure. Of course I am only too well aware that fools rush in where wise men fear to go and that when ignorance is bliss 'tis folly to be wise! Although I don't think Shakespeare involved himself with wiring modifications on his Volvo. :regular_smile:

Suggest you read this:

https://en.wikipedia.org/wiki/Light-emitting_diode

But basically an LED has no resistance so needs to have the current going through it limited. In small, signal lamp applications this is invariably done with a series resistor - the value of which is calculated to give the desired current. In higher power (lighting) applications it is usually done through pulse width modulation power control (far too complex for this application).

You can buy LED's with the resistor built in - that might be an easier option

https://www.ebay.co.uk/itm/5mm-Pre-W...KO5x5gOjxyEq8A

I get what you are trying to do but would add that the LED signals from the SCM were never intended to be used like this - if you get it wrong you risk damaging the ECU - so before you connect the new LED's I would test them with a 12v supply and multimeter to make sure the current draw is negligible.

The other thing you need to be certain of is many "signal lamp" systems are negative switching - i.e. the expect power to be connected to the LED and will switch on the negative side. Again you can check this with a multimeter.