Sierra ignition barrel and current

[davidimurray]

Just doing some more tidying up and sorting out on my wiring diagram. I calculate that with my circuit, the max current that will be drawn through the ignition barrel in position 2 is 50Amps. This sounds a lot to me - can the ignition switch take that sort of current?

I've worked it out by taking the fuse ratings for -
20A - Indicator,Reverse & Handbrake Lights
10A - LHS Sidelights, Tailights & Number Plate
10A - RHS Sidelights, Tailights
10A - Brake Lights & Dash

On the permanent live side of things, the load is 120A max excluding the starter.

[drury318]

On a Sierra loom and fuse box there is a black ign relay, you will find it has 2 normal size terminals and 2 really big ones, this will take the current ok if you put one in the circuit, Dennis.

[davidimurray]

Ah ha - Cheers Dennis

Looks like its time to incorporate another relay and update my wiring diagram.

[davedew]

David,

You could do as I talked about in your other thread and wire the side lights to a permenant live as per the original Sierra. This would remove 20A from your load and mean you do not need the additional relay.

Cheers

Dave

[Enoch]

side lights don't take anywhere near 20 amps (4 5 watt bulbs plus the panel lights)- more like 5 or 6. Most of the load will come from a live going direct to the fuses and then to relays.
Enoch

[davidimurray]

In between chopping up material for suspension bushes I braved to dig the sierra fuse box out of my big bag of wires. Had a look but couldn't fina a big black relay. My Sierra was an 87 GL - anyone know if they had them - will check the haynes diagram this evening.

Davedew - that is one option. My only reluctance is that when the car is parked up - any passer-by could switch the lights on.

Enoch - assuming all the side lights added up to 6 amps, that leaves 36amps to take through the switch gear.

One thing I have yet to check is the size of the wire going to the switch as I'm guessing this would be a good indicator of capacity. I'm currently leaning towards fitting the relay as it then keeps all the high current carrying wires out of the cockpit.

[davedew]

On the 1990 on models they do have an ignition relay. The only things this powers is heated / electric windows, foglights, wipers etc. In other words high powered ignition controlled items.

I understand your thoughts about passers by turning the lights on when the car is left unattended.
Your idea about another relay seems to be the right way to go to over some all the problems.

Cheers

Dave

[antonia800]

I am sure the lights have thier own relay preventing them being left on when ignition is switched off and i will be using relays for major current applications as they are easilly changed and allow the wiring to be kept simple