Thinkware F770-2CH - hardwiring question

[JT86]

Hi everyone,

After some previous hickups, I managed to install the F770 (both front and rear) and get everything working.

Everything working, except for parking mode as I still need to hardwire the dashcam. I have the Thinkware Hardwiring Kit, displayed below:

The manual (well, the small piece of paper included with the kit) tells me I need to connect the black cable to a ground, and then the other cables to a fuse which receives power although the engine is switched off, and another which only receives power when the engine is switched on (as you all probably already know by now).

I'm driving a Volvo V40 - there's a fuse box located on the passenger side, underneath the glove compartment (so not on the left (driver) side).

Let me stress that I am in no way an electronics aficionado, so to say. I already get slightly stressed when I need to wire a lightbulb, and have to doublecheck online or with family members to know for sure I'm doing it right

So, that being said, I did manage to use a multimeter to get a read on the difference fuses located in the box. I discovered that I need to read from one of the two metal points which "peek" through the plastic top cover of the fuse, in order to get a reading. If I'm not mistaken, some of them only give a reading on one of the metal points, which we'll get to later.

I identified the following fuses:
- fuse (61) (10A) entitled (freely translated) as "curtain for glass/panoramic roof"
==> however, my car does not have this (just a regular roof), so I wonder why the fuse is there. In any case, it receives constant power although the engine is switched off, so I could use this one?
- fuse (63) (5A) "collision warning" (constant power)

Finding fuses which do not receive power when the engine is switched off was almost harder than finding ones which do. I identified the following:
- fuse (83) (10A) "central locking fuel cap"
- fuse (84) (10A) "unlocking tailgate"
- fuse (86) (10A) "airbag & pedestrian airbag"

So now, I have the following questions:
1.) Am I doing this right? I have a feeling that the fuses I have identified should be the other way around; it makes more sense to me that a "collision warning" system would only function when the engine is switched on, whereas "unlocking tailgate" would receive power so it can be unlocked even though the engine is not running. Therefore, I'm not 100% sure I'm doing things right. My dashcam is currently connected to the cigarette lighter, and only switches on when the engine is actually running; so not when I switch on the "battery" by pressing the start/stop button without pushing the clutch (e.g. to listen to the radio, for instance). When I was reading the fuses, the doors were open and an interior light was burning: does this mean that the battery was actually switched on, and therefore I got faulty readings (although the engine was not running)? Or is it really about finding fuses which give power only when the engine is running?

2.) Why do I have fuses for parts which are not installed on the car? (e.g. panoramic roof curtain, collision warning); are these fuses then used for something else? Could I use these fuses regardless?

3.) Do I need to look for a specific amount of amps? Some are 5, some are 10...is there a minimum or should I look for a specific one?

4.) And then perhaps the most important question: how do I go about "installing" the wires? I've seen a tutorial where a guy just pulls out the fuses, wraps the metal wire around one of the fuse legs and pushes it back in. I've seen others where people use what is apparently called "add-a-fuse", and looks like some kind of "fuse extension cord" in my eyes. Is there a better way to do things? It seems to me that just wrapping the cord around one of the fuse legs is the more easy-going approach, whereas using an additional "fuse extension" would perhaps be better? Like I said, I have no idea.

5.) In case the first method is used, can I just simply wrap it around one of the fuse legs and plug it back in? Also, which fuse leg should I use? Does this correspond with the one which gives a reading when I touch the metal top part as described above?

I'm a bit anxious with regard to fiddling with electronics, also as this is a company car and I wouldn't like to wake up to a burning wreckage the next day, only to have firemen pull out a 3-meter power cord from the headliner and point out an out-of-the-ordinary kit which was amateuristically connected to the fuse box

So yeah...all help is really appreciated.

Once again, many thanks in advance!

 

[Maddog1974]

In all honesty as you openly admit you're not an electronics whizz i would recommend get it fitted professionally. On paper it's not too difficult but with today's vehicles it is important power is taken from the correct circuits as warning lights can appear on the dash regarding battery drains etc. Also when it comes to actually routing the cables to the camera it's important not to have the wires crossing over curtain airbags in the 'A' pillar etc.

If you are going to do it yourself i would suggest using 'fuse taps' like you say it's a fuse that replaces the one in the fuse box but it has a fly lead coming out for connection to external equipment. From what i remember from my auto electrical days vehicles often had fuses in when the equipment wasn't even fitted, a lot of the time they would even have the wiring present for the extra's too (Electric sunroof for example) I reckon it's cheaper / easier to have it all there.

 

[Dippy]

Your fuse descriptions seem to match this page. Seems that the V40 has another box under a front seat and of course one in the engine bay but these are not good locations for dashcam wiring.

1) As you have seen, lighting circuits are always powered and I would advise using such a circuit for the permanent power (or BATT) wire. So I'd choose fuse 60.
Switched fuses are indeed harder to find and what is important is to ensure that not only is the engine off, but the 'ignition' power is too. In older cars this was easy as its when the key is removed. The newer ones are not so clear. What I suggest is that you actually lock the car and arm the alarm system. Wait a minute and disarm the system and then only open the passenger door. At this point the electrical system should still be in the state it would normally be in whilst the dashcam is in parking mode. Now you can retest which fuses don't have power. Your reasoning about which circuits should be on or off is correct, however its not always the case. Personally I would avoid tapping into the fuses for safety circuits, not for technical reasons but for the reason you gave yourself in the second sentence which finished with a smiley. I'd guess that fuses 58, 77 and 82 could be switched power, and maybe fuses 59, 62 and 69.

2) Could be a production decision - it can be cheaper to make all fuseboxes the same rather than put resource into configuring them for each variant.

3) No, but you shouldn't need to tap into high current circuits especially if you attempt the wrapping wire around the fuse leg method (which I do not recommend).

4) Absolutely use an add-a-circuit fuse holder (make sure you get the correct size - mini).

5) As I don't recommend this method I shall not comment except tell you that a fuse is merely a piece of metal designed to melt if the current through it exceeds a certain threshold. When a fuse is inserted in a circuit, all parts of that metal are electrically the same.

Finally I have to agree with Maddog1974 - if in doubt, don't. This is especially because most add-a-circuit fuse holders have crimp terminals and these are not the simplest of things to get right.