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HELP! At my wits end.....
#1
Every few weeks I crawl under and in my car (Mk3 XTR) and try to find a way of running a cable from inside the cabin to the engine bay to wire my DRL's to an ignition powered source.
And every time,after a few hours pulling bits apart and then putting them back again,I give up.
Short of actually drilling through the bulkhead,which isn't an option,there are no grommets or anything to feed the cable through.

So,has anyone managed to run a cable through the front bulkhead that's reasonably easy to get to? I've tackled it from under the bonnet and under the car but to no avail.

Alternatively,is there somewhere under the bonnet,say the fuse box,that I can plumb into an ignition powered source? Or,connect to the charging side of the alternator,but which wire?

The reason being is that the DRL's are connected directly to the battery positive and should only light up when the engine is running and producing a charge,but,as soon as you open the door to get in,the DRL's light up for 20 seconds,and sometimes keep coming on and off several times.

HELP!

Another thing that puzzles me is that there is a bridging wire on the main battery cables,there is a short battery cable that goes between the positive and negative terminals,why doesn't it short out?
2010 XTR in black with bells and whistles

[Image: 5A50i.jpg]
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#2
(23-05-2012, 11:02 AM)XTR Wrote:  ... try to find a way of running a cable from inside the cabin to the engine bay to wire my DRL's to an ignition powered source.
And every time,after a few hours pulling bits apart and then putting them back again,I give up.
Short of actually drilling through the bulkhead,which isn't an option,there are no grommets or anything to feed the cable through.
...

...
Alternatively,is there somewhere under the bonnet,say the fuse box,that I can plumb into an ignition powered source? Or,connect to the charging side of the alternator,but which wire?
OK this may be a bit long winded but I've tried to be comprehensive in here:

Don't know if it helps but many Citroens (and equivalent Peugeots) have a dual position fuse in the cigarette lighter fuse position to allow the lighter socket to be permanently powered or ignition powered. If yours is like that, would that not be an easier way to get ignition switched power inside the cabin?

However, if you want power to your DRLs (explain??) ONLY when the engine is running AND the alternator is charging then connecting to ANY battery connected point (i.e. at the battery itself, at the alternator output, permanent cabin power etc. will NEVER achieve that; switched via the ignition or not.

You will HAVE to use a relay in conjunction (read: powered in parallel) with the ignition light (or the relevant connections at the alternator) such that the relay is energised ONLY when the ignition is switched on but engine NOT running (hence no charge and volts across the igniton light to power the relay).

Then, use the normally closed relay (i.e. closed when relay coil power is OFF - this happens when the alternator starts charging) contacts to provide power where you need it. Power input to one normally closed contact will need to be an ignition switched feed if you do not want power supplied until BOTH ignition is on AND engine running (and charging).

This WILL require a reasonable knowledge and understanding of electrics AND may STILL need wiring from the engine bay to the cabin. This is the classic way rally techs (who know ANYTHING about electrics) have wired their high power lamps for years such that the heavy current drain does not occur until (and unless) the engine is actually running and the alternator providing sufficient power to maintain charge.

One OTHER thought. MOST cars with high power air blowers these days have the mechanism described above that ONLY allows power to the blower motor AFTER the engine is running. My Berlingo van does this, as does my wife's Saxo, so it's likely yours will too. If you have such (easy to check: see if blower ONLY comes on with ignition on AND engine running) you're good to go.

Find the place within the cabin, behind the dash or the fusebox where the main power feed is provided to the blower unit power switch. Use THIS power feed, PRIOR to the switch to activate a normal relay provided with its OWN, separate fused supply. This supply can be ignition fed (belt & braces), or direct feed it, doesn't matter. Do NOT use the blower feed to drive anything EXCEPT a relay.

If ANY the above sound like they'd do the job, but you need more detail, PM me and I'll draw a diagram, scan it and send it to you to help explain things a little better - you'll need to have a reasonable grasp of electrical wiring symbols though.

Best regards.
[+] 2 users say Thank You to webmaestro for this post
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#3
wow webmeastro, respect. ::thumbsup:
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#4
Thanks for the (very detailed) reply.

However,I have a cable connected from the back of the cigarette lighter socket which will solve the power problem,but I can't find a way to get it into the engine compartment.
2010 XTR in black with bells and whistles

[Image: 5A50i.jpg]
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#5
OK let's take a different tack - and even more detail 8^) BTW I STILL don't recognise the "DRL" abbreviation you've used. I might just not be on the right wavelength but understanding it might give me some other ideas. Rather than trying to get a new cable with ignition-switched power from the cabin into the engine compartment, why not instead look for a point under the bonnet that is already provided with ignition switched power, there are usually several. There are at least three or four on my Berlingo fuse box - I checked. (picture can be supplied if need be.

I can think of a number of things that might fit the bill. e.g. ignition power to the ECU, Fuel pump (if fitted under bonnet), Carburettor/throttle housing heater, injection pump, ABS, et al. Looking at my Berlingo van fuse layout as an example I bet you have empty or spare fuse positions available in the main fuse box (under bonnet, not in cabin).

In most Citroens, even if the fuse is not present for a device, the harness wiring for the input power position to the fuse WILL be present AND have power. Because those positions have flat bladed fuse connections you will probably even be able to pick up ignition switched power directly from the fuse box by using a male faston blade (the smaller 4.6mm (??) size not the standard 6mm Lucar size) into an unfused power point.

The female faston contact is often there underneath the fusebox and in position ready to take at least the input blade of a fuse - you can see these easily from above the open fusebox. Such empty positions can quickly and easily be checked with a multimeter for available power (switch ignition on/off to verify it is ignition fed obviously!). In my case for instance fuse F24 is supposedly for a 5 Amp fuse that shows as FREE in the fuse layout.

You can make the whole thing neater by feeding the wire through an unfilled hole in the same fuse point from below the fuse box or even better try getting the relevant size/type of female faston for the empty hole (fitted from rear of fuse box) and actually using the fuse position with a proper fuse for your purposes. If you can get hold of a knackered fuse box with some of the wires still attached, the connectors can be removed from the old fuse box (usually with a paper clip, jeweller's screwdriver or similar) with a length of wire still attached and then you can solder the end to the end of a new cable with some heat shrink sleeving to keep the thing insulated and tidy. You can tell I've done this sort of thing before can't you? 8^)

Bottom line here is ... stop beating yourself up trying to get an ignition fed source of power from inside the cabin to under the bonnet when there are probably already several existing under bonnet sources already waiting and from which you can choose. Just ensure (use a multimeter/voltmeter) that you get the feed from the INPUT side of the fuse (if one exists) and use a new fuse & relay if high power stuff is to be connected.

What you are basically seeking is ANYWHERE under the bonnet where an ignition powered fuse point or relay exists. Remember though, on a relay, it is the ENERGISING power feed to which you want to connect NOT the output or input power feed. Once again, if the power that turns on the relay, i.e. energises the relay coil, is via the ignition switch (directly and NOT via an accessory switch) and the relay itself is under the bonnet you have an immediate source of ignition fed power at your disposal.

Same rule as before though, use the relay energising feed as the energising source for your NEW relay ONLY or as a supply via a NEW, separate fuse for low current draw devices (<1-2 Amp only, fused at max 5 amp).

One final point to re-emphasise, as you didn't seem to have picked up on the difference I highlighted previously. Doing what I suggest above will ONLY give you an ignition fed supply. It will NOT ensure that that supply ONLY works when the engine is running AS WELL.

For THAT to happen you MUST do what I explained in my first response and the ONLY source that can be used easily is the power across the ignition lamp. This ALSO exists under the bonnet but MAY NOT be directly or easily accessible unless you can easily access the separate wires into the Alternator. Sometimes it's easy sometimes not. If you can, then a standard Scotch-Lok type wire tap will give you the feed you need onto the ignition lamp wire - used to be labelled/called the WL (Warning Lamp) lead on the old Minis.

Remember, the ignition lamp is normally connected between the output of the Alternator (after the rectifying diodes internally) i.e. the main battery charge feed so a connection directly to the battery will provide this connection, and the Alternator field coil winding (via the slip rings). This ensures that as the Alternator output voltage rises and starts to drive itself with its own power (as opposed to drawing current from the battery via the ignition lamp) it effectively "switches off" the ignition/charging lamp (same voltage exists both sides).

Hence wiring a relay coil across these two points will power the relay coil ON when the ignition is switched on, thereby keeping output power OFF (since the normally closed contacts would be then be open). It will then LOSE its energising power as the alternator voltage builds up and the engine is running. Provided that the relay input power is ALSO fed from an ignition switched supply, output power is ONLY provided when BOTH the ignition is ON AND the engine is running as the relay will then be UNenergised and the normally open contacts will be closed.

N.B. Sometimes when doing this, it may be necessary for decent control purposes to use a transistor-based switch or "relay" which has a more accurate switch-off (within 0.7v of target or even less) than a standard coil relay and also consumes far less current. Again if anyone wants a circuit for such let me know. They're dead easy to design (and build).

Hope that all helps and doesn't confuse you more.
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#6
DRL = Daytime Running Lights
--------------------------------------------------------------

2012 Iron Grey XTR 110 with lots of bits and bobs.
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#7
Ah! Obvious once told. Shouldn't they be VSHL's - Volvo Style Head Lamps? ;-) Seems like everyone and his dog wants them now that high power blue/white LEDS are so easy to come by and produce. Well all my previous stuff remains as is. A relay should STILL be used and fused, but especially if any Halogen or other high energy/power lamps used e.g. Gas discharge. Otherwise lower rated contacts relay (or transistorised circuit) will be OK.

Good luck.
[+] 1 user says Thank You to webmaestro for this post
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#8
(24-05-2012, 08:48 PM)XTR Wrote:  Thanks for the (very detailed) reply.

However,I have a cable connected from the back of the cigarette lighter socket which will solve the power problem,but I can't find a way to get it into the engine compartment.

Did you manage to sort this out?
--------------------------------------------------------------

2012 Iron Grey XTR 110 with lots of bits and bobs.
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#9
He probably came to his senses and gave up tee hee.
I just use the SONRL lights that came with the van.. (switch on nighttime running lights) :-)
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#10
(07-06-2012, 10:33 AM)Trevor Wrote:  Did you manage to sort this out?

No,I've given up for now,got other projects on the go......
2010 XTR in black with bells and whistles

[Image: 5A50i.jpg]
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