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Most electrical items on the Berlina run hot, not off the ignition switch. I'm in the process of rewiring it to a new "Painless Wiring" fuse box and adding relays whereever I can. Rather than running most things hot, I'd like to have them on the ignition switch. So far, I have a relay on the fuel pump and high and low beam head lights. The brown wire off the ignition switch is the power switched wire. It's a light wire, maybe 16 ga (I'm guessing). I wonder if it's heavy enough to carry the low power load of several relays. I have 5 now and will probably be adding more.

Would it be possible to remove the ignition switch and replace the brown wire with a heavier guage one. How does the switch come out of a 1973 Belina?
 

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As far as I know, all you need for the relays is basically a signal. I don't know what the rating is off the top of my head, but I can't imagine the load on the coil side of the relay being all that high.

If your using the standard kinda of automotive relay, they look to use about 2watts
http://documents.tycoelectronics.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=VF4A-X0000-A001&DocType=DS&DocLang=EN

So about 6 relays all working at the same time would use about 1amp

So.. if a 16ga wire can carry 15amps then you should be able to hang 90 relays off of it.
Assuming my math is all correct. So.. I can't imagine your going to go past 12 relays. Or 2 amps.
 

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I concurr with damoj's reply.

Increasing the wire gauge won't buy you much, as the current handling capacity of the contacts in the switch will be the limiting factor.

You might want to invest in an ammeter that measures zero to ten amps, and just measure how much current the relays are drawing. I have such an ammeter, and find it valuable for automotive electrical work. For example, once you have your new fusebox installed, you can use the ammeter to determine what size fuse to put in each circuit.
 

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To get the switch out, remove the steering column cover, to and bottom. This may require removing the 17mm nuts and dropping the upper steering column a bit. You might also have to loosen the steering box attachment bolts if you have a solid-shaft steering column. Then remove the anti-tamper screw on the switch, which may have to be chiseled off. If it's on the upward side it's hard to reach. Then pull the switch straight out, towards the radio/console.

Andrew
 

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Discussion Starter #5
Ok, thanks for the analysis. I think I'll try to go with it as is.
 

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Discussion Starter #6
If the currents are that low, is it really necessary to fuse the low power side of each relay, or maybe one fuse on the brown wire off the ignition switch?
 
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