C5 - electrical issue

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atr
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C5 - electrical issue

Post by atr »

Hi again. along with the towing bar kit, I received the "Smart Bypass" unit. to my understanding, it requires a constant (no switched off by the ignition switch) of +12V, direct from the battery, or from a "live" point on the fuse box. here is a link to the pdf installation instructions.
http://www.rydertowing.co.uk/downloads/ ... ctions.pdf
please let me have your advise what will be the best point to connect the wire that will supply the power to the unit.
Thanx.
Avi

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GiveMeABreak
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Re: C5 - electrical issue

Post by GiveMeABreak »

It surely depends on the current requirements of that particular system as to which fuse you connect it to. Depending on that you'll be able to use a 'piggy back' fuse to link into an existing suitable fuse - maybe into one of the interior cabin fuse boxes like I did for my dash cam:

viewtopic.php?f=3&t=56750&hilit=dash+cam

Scroll down to the relevant part concerning fuses, their explanation and which ones you need. I wanted a switched fuse that goes off with the ignition, but my guide should also indicate a non-switched permanent live that you can use and the routing I used.

atr
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Re: C5 - electrical issue

Post by atr »

Hi Marc. I'll ask my spare parts shop if they have a "piggy back". any ideas how to route the wire from the fuse box to the trunk? I'm afraid it's a little complicated and I never done it before.
Avi

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GiveMeABreak
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Re: C5 - electrical issue

Post by GiveMeABreak »

See my link ^....

atr
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Re: C5 - electrical issue

Post by atr »

Again - I've looked into the fuse lists and I think that fuse G39 on fuse box A is the best choice. it says that it's for the passenger's electric seat
and since I don't have one and the fuse is 30A rated, I believe it might be suitable.
Avi

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GiveMeABreak
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Re: C5 - electrical issue

Post by GiveMeABreak »

There you go then. As for the wiring - my routing was from the rear window to the front fuse box - so you can just go directly from the boot area through to the fuse box Avi. Just make sure you get the right piggy back fuse sizes as these come in 3 sizes - but they are very cheap to buy and doa great job without you having to cut and bypass OEM wiring.

Just get one with the appropriate rated fuse that you need - so that the original socket is protected by the 30A as it should and the trailer wire can then use whatever they recommend if it is lower than 30A.

atr
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Re: C5 - electrical issue

Post by atr »

Looking at fuse box "C" for a point that is "live" - carries the +12V even when the ignition is off, I was surprised to find out that that is exactly the case on fuse F17, which according to the table posted by Marc, supposed to protect the heated rear screen and I wonder how is it possible that a circuit protected by a 40A fuse, thus can draw a lot of current and drain the battery shortly, is cut off by the ignition or am I wrong? I've checked it with a multimeter.
Thanx.
Avi

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GiveMeABreak
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Re: C5 - electrical issue

Post by GiveMeABreak »

You have to account for the fact that that although this particular circuit for the heated rear window in my link F17 is live at the fusebox, it is also controlled separately by the BSI - as are a lot of systems.

So the BSI will not allow the physical control button to operate the heated rear screen in this case, unless the engine is switched on and even then, it will be on a timer. This is how a lot of modern vehicles function. So although there may be permanent and switched lives at the fuseboxes, depending on circuit, there may also be further controls down the line that control the actual operation of the equipment by the BSI or by the engine fuse box via the BSI.

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Re: C5 - electrical issue

Post by atr »

Thanx Marc. if I got it right,then there is no obstacle to draw the current from this point , or would you recommend another place?
Avi

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GiveMeABreak
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Re: C5 - electrical issue

Post by GiveMeABreak »

I don't see a problem, but essential to use a piggy back fuse with the correct fuse rating needed for your specific towbar electrical harness. That will maintain the 30A needed for the heated screen circuit and allow separate protection for the towbar electrics. If I read your Ryder instructions correctly, it needs a 15A fuse. So you can buy the fuses you need cheaply enough and just put the right one in as needed.

As long as you allow yourself a small amount of spare wire length, then if you need to change the connection to another fuse later, you shouldn't run into problems.