Ignition wiring

I'm swapping my 90 set up in the cab for a cleaner look, noticably i'm installing a series 2a small dash panel with original ignition switch, 90 speedo and a few switchs to deal with other areas.

My issue is converting the wiring from a 1988 90 ignition barrel to work on the series 2a ignition barrel. Skimming through the tinternet i've come across a few items of interest, mainly the earlier series used a positive earth, later a negative earth...what does this mean exactly and will it effect the crossover?

I also found that the switch on a series 2a can take alot less ampage, apprx 12-15amp whereas the 90, alot more, is this due to a separate push button for starting?

Lastly has anyone done this type of conversion before? If so, any tips on the ignition side will be much appreciated.

ta

http://www.expeditionlandrover.info/ignSW.htm

The Positive earth as I believe was used on early series with dynamo, negative came later with the altenator, as for power through the switch try using relays to cut the amperage through the switch. This is something I am currently working on for mine so could be very wrong, best of luck with it.

Interesting. I'm hoping the switch i have has come from a later alternator version, i dont know much about series themselves and when the switch happened.

From what i can see, one thicker cable runs straight to the glow plugs, as mine haven't even been connected in the past 2 years, i'll forget that cable for the time being and concentrate on the other thicker brown ( from the alternator i think 45amp ).

How would you recommend using a relay to downsize the ampage, and would this not affect the starting process? I was lead to believe the starter relay opens the circuit for the battery power to be released to the starter motor, so the brown cable to the ignition is basically a feed for the glow plugs, and the brown/red cable from the ignition is as described above, a glow plug feed.

This is beginning to venture into 90 territory, but the basics of how the series ignition works over the 90 version would be helpful

ta

Can't really help you with this one, the starter relay is a solinoid; you run a small current through the coil which magnetises and pulls on the contact (something like that) which allows the heavy current to start the car. Relays work simular, you just need small wires for the coil to turn on the relay and the larger current flows through the relay. You can run just a neg wire to the switch and earth it after the switch to get the circuit to operate a relay so no power in dashboard area.

I think the fender ignition is rated a lot higher because the Series ones kept melting - seriously.

I'm looking at these issues on my SIII rewire too. Relays basically use a figure of 8 circuit. You do your switching in the cab using a small current, this is picked up by the relay which closes the high current circuit which does the job in hand e.g. running your head lamps, or engaging your starter solenoid. This stops all that high ampere electricity from having to run through your delicate little Series switches.

I intend to relay headlamps, glow plugs, starter circuit, horn and spots. Might do sidelights and indicators too but that's probably overkill, especially if I fit LED's in there anyway. This way is safer, and more efficient. Not only will your wires not melt, but there will be less resistance caused by those wee thin wires and old fashioned switchgear.

its not difficult to use earlier system to run later truck ,as i said earlier brown battery live come from starter (only because its a easy location)to ingnition switch and other un ignition switched live functions ie side lights ,red white wire could run straight from switch to starter solenoid or you can fit a relay inbetween if you like as later vehicles but not necessary early starters draw as much current as later ones and its only the solenoid which is a relay of sorts that goes through switch

Ignition all sorted, now to the headlight switch.

Had a google, but only come up with a positive earth diagram for the switch/wiring, does anyone have a diagram for the wiring for a neg earth version or are they the same?

Found it!

http://www.roversnorth.com/store/images/category/medium/LR-page83.pdf


Alot easier to follow than the haynes