Finding a spare Ignition feed?

[davegsm82]

Are there any recommended places to pick up a reasonably high current ignition feed at the front of the bus? I have installed electric windows but due to the illuminated switches (illumination not on a separate feed) I need them to go off with the ignition.

The feed to the windows already has a fuse so it doesn't need to be fused.

Cheers, Dave.

[itchyfeet]

ignition feed on rear of fusebox, if you need higher current run it through a relay from a fused battery feed

[davegsm82]

Thanks Itchyfeet, I presume Fuse 18 is usually unpopulated? (Should mention that mine is the later blade type fuse box).

Cheers, Dave.

[itchyfeet]

No it's already in use, does something quite minor in power terms like handbrake light and brake fluid light.
fused at 10A normally but you could up it to say 15A

How much power do you need?

that is a pic of a late fusebox, I checked your sig before posting.

[ajsimmo]

That's the terminal I usually use for the feed to an LPG switch, as it remains live on cranking. May be better to use the adjacent spare terminal which is isolated during cranking (don't know the number from memory - I recommend you check it with a test light).

Sent from my ONEPLUS A3003 using Tapatalk

[itchyfeet]

Ah yes G3 is from the x rail ( switched off on cranking) via fuse fuse 12

Unlikely you would want to wind your window and crank but it helps if you did, good thought Andrew

[davegsm82]

Ok, Thanks for the input chaps, I've now got it sorted and found out some interesting things.

Instead of tagging on to G2 I've instead used G1, which was originally the power feed for the rear under-seat blower motor, since I removed the blower and replaced it with an EBER D3LC then this was redundant.

There was some slightly dodgy wiring round the back of the fuse box so I tidied that a bit, including moving the ignition feed for the radio onto G2 which seems to only feed the handbrake warning lamp.

While I was messing about I also found that terminal G3 comes via fuse 3, which serves the Cigarette lighter and interior lights among other things, therefore G3 should be permanently live (didn't check). Fuse 3 is also listed as serving central locking so this would be a good place to put aftermarket RCL systems. Mine just goes straight to permanent live with an inline fuse.

So, interesting things.... I'm interested in the Relay 2 position, which is unpopulated in my bus. It's a very high current relay, the main terminals are larger than 1/4" and are probably 3/8" or 1/2" or whatever the next largest common denomination is. It feeds terminal 'N' on the back of the fuse box, again it's a large 3/8" terminal and is unused.

If a suitably heavy duty relay was fitted to this position, and terminal N wired to the fuse which feeds the high speed cooling fan then it would provide a second high current path to the fuse box ignition line, so that the voltage drop from front to back is reduced. If I had a wiring diagram for the fuse box I could make this clever enough to switch out should the cooling fan come on full power, but I'd need a diagram for that which I don't have.

I'll have a bit more of a poke about in this area and see what I can come up with, might help keep the lights brighter and the wipers faster.

Dave.

[itchyfeet]

not convinced about G3
download diagram here, alot is common across models
http://syncrosport.com/info/wiring/" onclick="window.open(this.href);return false;

[davegsm82]

not convinced about G3
download diagram here, alot is common across models
http://syncrosport.com/info/wiring/" onclick="window.open(this.href);return false;

Yea, fair enough, seems like it should be F12. Odd because when I pulled F3 it went dead. I'll have another poke around in a few days and confirm or deny my own claim.

Have dredged through my box of vehicle wiring junk and came upon this relay, a number 100 and it's holder from the Sharan I stripped when I was doing my TDi install. The holder will provide the spade and a length of cable for terminal N and the relay works when installed into number 2 relay position. I'll try this out in the next few days too.

[itchyfeet]

Yeh pays not to guess with electrics, use a wiring diagram first and test second.

Not sure if you used a Voltmeter but they can lie to you, they detect voltage when there is no current available, sometimes you get voltage through another off component.

That's why Andrew reccomended a test light, it needs current to illuminate so is a tre test of 12V with available current.

[davegsm82]

Aye, no worries on that point, I'm an electrical engineer so I'm used to this stuff.

The reason for this phenomena is high input impedence of multimeters, it basically puts zero load on the terminal so it can suffer from leakage from adjacent terminals.

A test lamp is ideal for this stuff.

[itchyfeet]

I'm an electrical engineer so I'm used to this stuff.
.

Snap,

sorry didn't mean to teach you to suck eggs

[davegsm82]

sorry didn't mean to teach you to suck eggs

Not at all!

So, does anyone know what the relay in position 2 is for?

[itchyfeet]

vacant I think
https://club8090.co.uk/forum/viewtopic.php?f=39&t=157168" onclick="window.open(this.href);return false;

[davegsm82]

Spot on. Found it on page 3 of the JX wiring manual on Syncrosport's website.

Fairly sure I've worked out it's original purpose, looks like it has the normal connections for +ve, ign, 0v, connection to starter signal and a few other unidentified ones so it looks like it's some sort of high current relay with load shedding, activated during starting. If I didn't know any better I'd say it was probably a glow plug relay, since looking at google would suggest that this same fuse box was used in other models so it would seem probable that it's used for the GP's when the fuse box is used in vehicles with front mounted engines. The heavy 'N' terminal also connects to fuse S5, which I would suggest feeds a glow-plug lamp on the dash. Pin 5 connects to the Tacho signal from the alternator, probably used to switch off when it detects engine running.

This should fit my purpose ok