What Wire To Use For Signal From Reverse Light To Car Stereo?

[wwarby]

Hi all,

I've ordered myself a reversing camera to install this weekend which I will connect to my new car stereo. The stereo's wiring block has a purple/white wire marked "reverse gear signal input" which I've figured out I need to connect to the wire that goes to the reverse light. My question is, what kind of wire do I need to buy for this - as in what thickness or any other important criteria that might exist for selecting what to buy. I know what it looks like obviously - it's the same kind of wire that's used for every connection in the ISO connector, but it's surprisingly hard to find a definition of that wire on Google and I want to order the wire online so I want to make sure I get the right stuff.

Also, do I need an inline fuse between the reverse light and the stereo or is it safe to just wire it straight there? And if I need a fuse, what kind? Thanks in advance for any pearls of wisdom anyone can share on this - I'm a bit of a wiring novice but I'd rather try these things myself first before paying somebody in a shop to do it.

[troy45]

Does your new stereo come with a canbus box? assuming it's like one of the generic chinese built sat nav/DVD units a few owners have installed(myself included)

For those units you use the reverse light feed to provide power to the camera and it then sends it's signal to an input socket at the rear of the head unit. The canbus box sorts out that the car is in reverse so switches the head unit to the right input channel.

There's a really good write up on reversing cameras in the guides section - generally you can just use something like 1.5mm cable, but me having a fair amount of electrical experience I can tell what's suitable pretty easily. Again the guide to installing reversing camera gives good info on what cable can be used and where to get it from.

Not used an inline fuse with my set-up, as it's fed from the reverse light feed that's already fused.

Apologies if the way your stereo connects to the reverse camera isn't the same as I've described.

[PhillFocus]

Ya when I did my mates I just did it to reserve wire on the lightz

[wwarby]

Does your new stereo come with a canbus box? assuming it's like one of the generic chinese built sat nav/DVD units a few owners have installed(myself included)

For those units you use the reverse light feed to provide power to the camera and it then sends it's signal to an input socket at the rear of the head unit. The canbus box sorts out that the car is in reverse so switches the head unit to the right input channel.

There's a really good write up on reversing cameras in the guides section - generally you can just use something like 1.5mm cable, but me having a fair amount of electrical experience I can tell what's suitable pretty easily. Again the guide to installing reversing camera gives good info on what cable can be used and where to get it from.

Not used an inline fuse with my set-up, as it's fed from the reverse light feed that's already fused.

Apologies if the way your stereo connects to the reverse camera isn't the same as I've described.

Apologies for the delayed reply - busy week. I'm not entirely sure what a canbus box is, but it's a European model Pioneer AppRadio 4 (SPH-DA120) which comes with two wires relevant to the camera. The first is a yellow phono in for the video feed which is a 6 inch wire hanging out the back of the stereo, and the second is on the wiring block that came with the head unit, which looks something like this picture (though not exactly the same):

If you look at the loose brown wire in that diagram, I have a loose purple one like that which is labelled "reverse gear signal input".

I did actually try to read the installation guide you referred to, but it's full of images which don't seem to want to load, making it quite hard to read. I'll give it another go. Thanks very much for your advice!

[troy45]

The canbus box is an extra box wired in between the 2 connectors which interrogates some of the canbus signals which would usually go to the head unit. Not sure exactly what this helps with but do know with mine it would switch to the camera input screen before I'd wired the camera input to the unit. Looks like your unit wouldn't do that and you do have to take a reverse input direct to the head unit.

I'd say to still power up your reverse camera off the reverse light wiring, then either pick up similar from the reverse switch wiring (but this may be hard to trace as it'll go from engine bay into the GEM/cabin fuse box) or when you run the phono type cable from the camera to your head unit put in an extra cable to use for your reverse input, and also fed from the reverse lights as per the camera power supply. That would make the camera only power up when you put the car in reverse, plus gives you the necessary input to the head unit.

You may also be able to pick up the output from the GEM going off to the reverse light saving you having to run the cable the length of the car - though with my kit the long cable for the phono input also had a 3rd external wire spare which you could use if the camera kit is similar.

Last thing, with the Camera Fitting topic, if the OP's photobucket bandwidth is exceeded it won't show the photos. But if you right click on the little photo icon and copy the image URL then enter this into your browser you can then see the photo.

Simples :)

[wwarby]

The canbus box is an extra box wired in between the 2 connectors which interrogates some of the canbus signals which would usually go to the head unit. Not sure exactly what this helps with but do know with mine it would switch to the camera input screen before I'd wired the camera input to the unit. Looks like your unit wouldn't do that and you do have to take a reverse input direct to the head unit.

I'd say to still power up your reverse camera off the reverse light wiring, then either pick up similar from the reverse switch wiring (but this may be hard to trace as it'll go from engine bay into the GEM/cabin fuse box) or when you run the phono type cable from the camera to your head unit put in an extra cable to use for your reverse input, and also fed from the reverse lights as per the camera power supply. That would make the camera only power up when you put the car in reverse, plus gives you the necessary input to the head unit.

You may also be able to pick up the output from the GEM going off to the reverse light saving you having to run the cable the length of the car - though with my kit the long cable for the phono input also had a 3rd external wire spare which you could use if the camera kit is similar.

Last thing, with the Camera Fitting topic, if the OP's photobucket bandwidth is exceeded it won't show the photos. But if you right click on the little photo icon and copy the image URL then enter this into your browser you can then see the photo.

Simples :)

Yeah, mine definitely wants to get connected to the reverse light I reckon, and as it happens, the camera arrived today and the yellow phono cable for the video feed has an ingenious design - poking out each end of the cable is a thin red wire that's clearly designed to take the reverse light signal back up to the front of the car with the video feed. So basically I have to run the video feed up there anyway and I get the second wire for free.

I reckon I'm set for how to do the camera now at least in terms of wiring - I've already previously fitted parking sensors so I know how to reach the feed for the reverse light. Whether I can find an easy route for the cable from front to back is another matter - I always seem to have terrible trouble removing interior trim panels so I'm hoping I won't have to remove many.

The thing I'm stuck on at the moment is with the stereo wiring - I need to run a cable to the handbrake switch and I can't figure out how to get to it - those centre console panels seem impossible to remove! There's a guide for that too - also with blocked Photobucket images. I tried your suggestion of copying the image URLs and pasting them into the browser's address bar but it didn't work for me. Perhaps they've got wise to that trick? It's annoying because I really want to see those images - I imagine it would help immensely both for the stereo and camera installation.

[troy45]

I've had lots of practice now removing the trim panels to route cables to the front of the car as I decided to run my cable along the floor - is a lot easier if you follow the guide and route up along the edge of the headliner. Was trial and error for me but I'd be able to do it a load quicker now. Could be simpler if you've got a 5-dr instead of my 3-dr with the larger rear quarter trim panels

I tried an example with the photobucket links before I made my last post and it worked fine. If you're using Chrome just right click and pick 'copy image url'. For IE right click then select properties. From the properties window copy the whole url address then paste that into address bar and should work.

[wwarby]

Success!

Had to go to Maplin and got a couple of extra bits of wire and some snap clamps to make the wiring joins and had a few "WTF isn't this working???" moments but got there in the end. I ran my cables along the floor like you - I bought a bumper-mounted camera so that seemed like the easiest route and actually, getting the cable from front to back was quite easy - it was joining the wires in the right places that I found hard - testing them over and over with a multimeter to make sure I'd done it right and didn't blow up the camera.

Everything is working perfectly now and fully fitted except for one thing - I cannot - no matter what I try - push the stereo back far enough to clip itself into position. Why oh why do they make that space so f'ing tight! there's such a jumble of wires back there and you can only do so much to tuck them out of the way before you have to move your hand to push the stereo back. I might end up paying for a stereo fitter to literally just push my stereo into position at the rate I'm going!

[troy45]

Good to hear you've got the wiring sorted now for your reverse input - things like that aren't so complicated once you've had a go and seen for yourself :)

I also had problems getting the head unit into the dash and sit flush - with my unit the phono cable connector stuck out a fair way once connected at the back of the unit. Got a little 90 degree elbow connector from you know where ;) which gave some more clearance at the back. Also spent some time pushing the ford wiring as far over to one side as possible. Still took time but got there in the end.

[wwarby]

Good to hear you've got the wiring sorted now for your reverse input - things like that aren't so complicated once you've had a go and seen for yourself :)

I also had problems getting the head unit into the dash and sit flush - with my unit the phono cable connector stuck out a fair way once connected at the back of the unit. Got a little 90 degree elbow connector from you know where ;) which gave some more clearance at the back. Also spent some time pushing the ford wiring as far over to one side as possible. Still took time but got there in the end.

I remember having this problem years ago but my last few head units have been single DIN so buckets of room to manoeuvre. I do wonder why Pioneer have made my new head unit (AppRadio 4) so big anyway - it's a glorified tablet PC with no CD player or moving parts.

Tomorrow I'll try disconnecting all the wiring to see if clumps of wire are causing the problem. Such a frustrating and unnecessary problem given how easy it would be to make the space slightly bigger or the stereos slightly smaller. Grrrrr!