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One thing that had always bothered me about my car (and 02's in general) is the wiring arrangement in the engine bay between the battery, starter, alternator and feeds to the fuse box and ignition switch.  Given the large amount of unfused wiring involved in this lot, it somehow still managed to be as ugly as sin and generally let the car down as being a bit of crappy engineering. 




Things like this get my goat, multiple wires jammed into an inappropriate crimp terminal. That’s the main feed for a number of circuits plus the alternator feed wire. Very poor.




Some more ‘before’ shots.


I had been planning to resolve this for some time in parallel with a few other electrical modifications.  This includes:


  • Headlight relays - I have previously installed two headlight relays using an add-on loom (home made) but I wanted to integrate this wiring better with the factory loom and make it generally tidier.
  • Provision for driving lights - Having polled the FAQ regarding lights, I bought some eBay bargains that I think are actually quite good. 
  • Provision for an electric fan.  This will be primarily for the air conditioning but I am hoping that i can justify removing the engine driven fan 
  • Provide a high current feed to the rear of the car (under rear seat).  Initially this was to be used just for an amplifier but I will also use this for my trunk mounted air con and remote operated trunk latch
  • Provide a 60A circuit breaker - This will protect a lot of the currently unprotected wiring plus the new high current feed to the rear.
  • New 'military style' (that is how they are referred to in Australia) battery terminals that are more substantial, have good insulators and allow multiple cable connections.
  • New custom battery feed and ground cables in 25mm2 welding cable.
  • New fuse box for the headlights, driving lights and electric fan. I am also going to fuse the horn as this is currently not fused on my car.
  • A general tidy up of existing wiring, upgrade to alternator wiring (following an upgrade to an AL41X) and re-wrapping of the engine loom.


I had previously added some high and low beam relays to the car around the time I did a conversion from old corroded Euro-buckets to H4s in US market buckets.  This was accomplished by making up looms using the instructions posted in Bill Williams' Article on the subject.  The individual relays are triggered using a connection into the left hand side bulb socket and, in my case, the supply taken from the alternator B+ terminal via an inline fuse to power both relays.  This approach always worked well and certainly achieves its aim of being a 'no cut' means of upgrading the headlights but I wanted it to be better integrated with the car's wiring.


I also wanted to take the opportunity to upgrade the actual relays used as I had heard some horror stories about complete 'light out' failures due to relays.  These had ended up as pretty catastrophic when high beam had been lost at speed on a dark road.  To be fair, as a context, these stories came from off-roading friends describing situations occurring after driving for 6 hours in the dark at high speeds on unmade, corrugated roads but they still made me think.  What was prescribed is a particular type of Japanese made, twin headlight relay (the New Era NLR-132 relay).  These New Era relays, while not sounding that special, are legendary amongst the Australian off-roading community for their reliability.  General opinion (amongst off-roaders) is that if you don't use a NLR-132, you should have a set-up with 4 X standard Bosch style mini-relays with separate high / low relays for each headlamp to minimise the chance of losing all of your lights.  How necessary this overkill is in my little 02, squirting around city streets is unclear but I like the 'packaging' of this dual relay so I bought one with the intention of wiring into my car when integrating the upgraded relay loom wiring into the cars existing wiring loom (and pulling out the factory headlight wiring).





Wiring diagram for the relay. 


Similarly, I wanted to make provision for some driving lights to be controlled by my high beams.  These could actually be powered directly from the same relay output as the high beam, assuming no greater load than 30A in total, but I wanted a further element of redundancy so these got their own relay, this time a conventional 5 pin mini-relay (with a normally open '87' terminal for each light) and fed from their own fuse.  The fuse for powering the driving lights is contained within a new fuse box, connected via an 8 AWG connection to the main 60A circuit breaker in the main feed.  This 4-way fuse box also provides a 25A fuse for the SPAL electric fan I will be installing with my air conditioning.




The driving lights are styled after off road lights and so come with a length of stainless steel corrugated conduit. I secured this properly in place internal to the light bodies and sealed it up with some heat shrink and crimp terminals. I like bullets for this kind of connection as they have a massive surface area and, quite frankly, I have stacks to use up. 




I made up new battery cables using 25mm2 welding cable. While still very flexible, this has a very tough, double insulation and is terminated using crimp ring terminals on each end. I added some corrugated conduit to further protect the cable where it was secured to the bottom of the battery tray and to the wiring clip on the engine block.  I added an insulation boot to the ring terminal to protect the starter motor terminal. 





Also attached to the starter terminal stud is a new alternator supply cable which runs directly to the alternator and the wiring for a starter relay that a previous owner had installed to stop the ignition switch from having to switch the solenoid current.  I am going to keep this arrangement but tidy up the wiring. 


The relay is screwed to the brake servo bracket with one wire running from the main starter terminal (with 12v) to the relay contact and then back to the ‘50’ terminal on the solenoid. The pair of factory black wires that would normally go to the 50 terminal are spliced to a thin wire which goes to trigger the relay coil. Works fine. 








After - the black wires from the ignition switch have been rerouted directly to the relay and the wiring between the relay and the solenoid has been secured and protected with heat shrink and corrugated loom.


The new alternator feed wire runs directly between the alternator and the terminal stud on the starter and then via the battery cable back to the battery. I thought it was a better arrangement than running a longer wire through the wiring loom as the factory did, particularly when increasing the size to 4 AWG.  This was given additional mechanical protection with corrugated split loom and heat shrink along with a new insulation boot on the alternator connection. The ground connection from the alternator body was also upgraded to 4 AWG as well. This should be more than enough for the AL41X alternator which is 65A. The stock wiring in 4mm2 wire is only just good enough for the stock alternator, so when upgrading your alternator you should really think about upgrading the wiring as well. This could be accomplished by running an additional wire, in parallel with the factory wire and direct from the alternator to the battery terminal. 




Bad photograph showing the new wiring to the alternator.  You can also see the wiring loom that carries the temperature gauge wire, a wire for the electric fan (not terminated) and the D+ wire for the alternator (I reused a length of plastic tube from the original loom to protect this where it runs outside of the corrugated conduit). 


I added some new grounding studs to organise the grounds for all of the new equipment.  I used 5mm bolts with a nut and spring washers to attach to the panel.  I then add the ring terminals and tighten down with another nut and spring washer.




The new ground studs (actually bolts).




Final arrangement, wrapped in Tesa fabric loom tape (that is amazing stuff). From the left: fan relay, driving light relay, twin headlight relay, original horn relay and 4-way fuse box. The sub-loom for the driving lights and electric fan can be seen running past the new ground studs and through the hole in the front panel.


The last change was the ‘military grade’ battery terminals.  These are naturally more substantial than most and are designed to accomodate multiple cable connections by using a 10mm through bolt to connect cables with ring lug terminals.  The positive carries the 4 awg main feed to the circuit breaker as well as the 25mm2 main battery cable which goes to the starter motor. The negative terminal carries a 25mm2 cable direct to the engine block via a 10mm bolt underneath the alternator. The other wire is a 3 awg pre-made cable which runs from the battery to ground at the side of the battery tray. The battery terminals are then both fully covered by soft plastic insulating covers. 




Negative terminal showing crimp lugs in place. 




Terminals with insulation in place. 


Overall this was a job that didn’t introduce a lot of new functionality but does allow me to feel good about the wiring, knowing that it has been adapted to my requirement. This is a fundamental bit of work prior to my planned work to add other electrical goodies like a stereo/amp, air conditioning etc. 









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Posted (edited)

Holy shit dude.  Big write up after a lot of work.  Looks nice.  Well done.

Edited by irdave

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