Cut out circuit - yes but, where? (and the Purple Wire explained.)

[anthonym]

I fear I have been exceedingly dumb, of which usually I am blissfully unaware.

The cut out switch circuit. 

It must receive battery feed to one side and then deliver that feed to somewhere else from where to be used by everything. The cockpit iirc picks up a feed from the cutout switch itself.

However, I have never considered where the engine bay components get their feed from.

It must be the distribution pole located just in front of the battery? So anything fed from there is subject to cut out and anything fed from the battery positive itself is not.

So while inserting inline fuses fed from the battery positive I have been "disabling" the cutout.

Is this correct? That I should be taking feeds from the distribution thing, not the battery positive? 

Anthony

[SM25T]

Can you add a photo of the distribution pole you mention ? Is that fed from the cut out switch ?

[Jonathan Kay]

What do you want to isolate?

And does it need to meet any regulations?

Jonathan

[anthonym]

@jk What do I want to isolate? This is the cut-out switch... Everything.  

@sm25 that was really my question.. so many wires I'm not sure. 

I'll see if I can see where the cutout wire goes and add a pic in a bit. Adding a busbar fuse box will significantly reduce the number of wires going to the battery and the distribution pole.

[rj]

I have, unlike most others, put mine on the negative side of the battery.

This simply because then the worst that can happen, if the wires are damaged, is that you can't isolate the battery. If it was the positive side you could end up having the unswitched supply short to earth which I don't fancy.

[anthonym]

I'll have to think about that

[anthonym]

 

[TomB]

Ive never managed to work out why, but my headlamps, sides, main beam & dash lights still work when the cut off key is 'off'.  Its got me stumped, one day ideally Id sort it out! 

[rj]

Tom,

Sounds like your master switch has been put in the ignition switched circuit rather than the battery feed. This may prevent immobiliser etc from discharging the battery, but won't prevent the car from catching fire if you crash and one of the main wires is cut.

[SLR No.77]

Tom, my car was wired like that when I bought it ... along with a load of other dodgy wiring which is why I rewired the engine loom. The best way to sort the FIA switch is to go back to the original Caterham install instructions and wire it as they intended.

Stu.

[anthonym]

anyone got a copy of that (Caterham original wiring diagram for FIA switch) or a linky?

[Paul Deslandes]

http://www.fastgrandad.co.uk/documents/S3%201995%20Build%20Manual/Section%2014.%20Optional%20Extras.pdf

page 18

[anthonym]

I can't see an FIA diagram in there - right doc?

[rj]

Long way down (page 18) there's a sketch of the switch with a description

[Paul Deslandes]

Also on the same link, Section 14.10 describes the installation and functionality.  Page 8, 9 & 10 refer.  Diagram towards the end on page 18 as noted above.

This is straight out of the CC manual supplied with my 2 litre Vx car in 1995.

Paul

[anthonym]

Sorry; I did look but did not see. I will go again. Thanks for patiently explaining.

edit: come to think of it I have an ‘87 build manual, I’ll look there too.

[anthonym]

  yertiz:  instructions in next message.

 

thanks

 

FIA-Switch-diagram.pdf

[anthonym]

a bit of an "ouch" reading that. Where it says "purple from vehicle loom - Rover K Series" I have a feeling at Schloss Dyke there was a problem with this feed and I cut it (under the bonnet, not in the cockpit). taking it direct to battery via a fuse... may explain where I have disabled my cutout.. so where it has double white from ignition switch, I have no longer cut the ignition, just the battery. and I had no idea.

and: this "optional extra" explains why the purple and brown leads exist in the engine bay as those two wires joined by a fast connector (which is renowned for being faulty), because this extra requires these two to be separated and extended.

 

Section 14. Optional Extras copy.pdf Here's the text, apologies for typos, Paul Deslandes linked file above is the master source compared to this ocr from it (but links often fail)..

14. 10 Battery Master Switch

. 1 A master switch  kit. has been produced  by Caterham  Cars to enable  tlte fitment of an Autolec battery master switch. primarily for competition purposes, but also for security. This comains the following components:

Autolec Battery Master Switch with fixing bolts

Main Cable (red) Starter Solenoid 1.0 Master Switch

5          Female Lucar  connectors  and  insulating  covers I        Male I.ucar COIUlCCtor

3          Ring terminals (2 x 1/ 2 ", Ix   5mm) Protection "Eyebrow" and fixing boll

All necessary cables and sufficient cable ties

Please refer to tl1e wiring diagram Fig. 14.10. witJ1 this kit.

We recommend fitting the switch in lhe triangular section of the right hand windscreen stanchion and a scale  template  is  included  on  rig.  14.10  Trace  or  cut  out tJ1is template and use it to mark and drill tJ1ree holes in tJ1c aluminium.

Remove tl1e nibber cap from lhe switch and insert it from the inside of me scuttle securing with tl1c bolls supplied. The rubber cap can be replaced on me switch but leave tl1c key out for tl1e tinle being.

Remove tlle existing battery to starter solenoid cable (red) completely iliough it  is reused later.

Disco1111cct tlle two brown wires from tlle positive terminal of tl1e batte ry, cut off tl1eir terminals and join lhe bare wires t.ogetl1er. Solder to lhis joint ilie additional

brown wire provided insulating well wilh insulating tape, and attach the 1/2" ring terminal to the oilier end.

This new wire is routed along  the chassis  tube above the gearbox,  up tluough the wiring loom grommet in tlle transmission tmmel cover and tllen behind the dashboard t.o the switch, connecting il to eitl1er of the main terminals.

Attach tl1e new red main battery cable to ilie starter solenoid and following me chassis members, run lhis above tl1e gearbox, tluough the wiring grommet and along lo tl1e switch attaching it to tl1e same tenninal as the brown wire.

Ford Engined Variants

11.8 Unclip the black plastic cover from me rear of ilic steering lock, protecting tl1e ignition s witch lem,inals, and remove tlle terminal  witll me  two  white wires attached to it.

10.9    llsing tl1e male Luc.ar connector, connect this to one of  tlle  while  wires contained in tlle kit and having attached a female Lucar connector and  an  insulator  lo lhc olher end of tlle wire, com1ecl it in n1m lo one of tlle 'Z' terminals on tl1e back of  tlle master switch.

10.JO Attach a female Lucar connector and insulator lo each end of me second white wire and connect tltis between me remaining ·z· tem,inal and the ignition switch where

tl1e twin while wires were disconnected. Rover K Series Cars

10.11 Disco1mecl the purple power lead in tl1e main loom from ilie brown lead in tlle engine loo m. Extend and connect. the purple lead to one side of the tcnninal Z on tl1e battery master switch. Extend and connect tlle brown  wire  to ilie oilier lenninal  Z on the battery master switch, see Figure 14 . 10.

All Variants

IO.12 Solder each of tl1c black wires supplied to each end of tl1e resistor contained  in the Aulolek kil and insulat e with tape. Attach an insulated Lucar connector to one wire and the 5rnrn ring terminal lo tlie other. Connect tlie Lucar end lo tlie 'W'  terminal  on  tlic master switch and earth the ring terminal to metal at a convenient point.

10 . 13 Fit the green wire with suitab le connectors and attach it between tlle remaining 'W' terminal on the master switch and the main tenninal lo which the brown and red  wires have been attached.

10.14 finally the original red battery cable removed earlier should be routed from tlle remaining terminal on tl1e master switch, tllrough tlic grommet, and along the chassis tube lo the posit.ive terminal on the battery. CAUTION do nol coru1cct to tl1e battery until tlie cable is routed and connected to tl1c master switch.

10 . 15 Tie all cables to tlle existing loom using tlle cable ties provided and take care to ensure tllat all connections arc well insulated and no wires are hanging loose.

10.16 To test tlic system, turn tlic master switch to the on position and check that. the lighL work. Start the engine and while the engine is running tum the master switch  l0 off, Ilic engine should immediately die. If tl1ere is a fault recheck  your wiring and if  this cannot be traced contact Caterham Cars.

IO.17 Please note tl1at on no account should you reconnect the battery or run tl1e engine until lhe switch wiring is complete or damage can be done to l11e alternator.

IO.18 On K Series cars it is not advisable to switch l11e engine off on tlle  master switch except in emergencies as this will wipe the memory of Ilic ECU. While no permanent damage will be done, it will result in initial rough  running until  tllc ECU  has been able to re-programme itself.

10.19 On Yauxhall Injection cars. to protect tl1e E.C.U.. the E.C.lJ. needs a permanent power feed that is not switched by the cul oul switch.  To  provide  this,  remove  me white wire from tl1e plug connecting the engine harness lo tl1c vehicle loom. (N. B. this wire should be removed from Ilic engine harness side) Extend this wire ,md fit a ring terminal to its end, where it bolts to tllc positive terminal of the battery.

I0.20 Where the cut off switch has been filled for racing purposes il will also be necessary lo fil the "eyebrow" shield around il lo prevent the switch being damaged in a side on accident. This is fiued to the windscreen stanchion by substituting the existing plated caphead boll for the longer bolts supplied with l11e kit.