Starter relay wiring

[maxdog]

Hi
The first snows are falling so it's time to plan my winter work projects .So can I confirm my understanding of the reasons for installing a "starter relay" ?
The purpose of the relay is to reduce the current passing through the the ignition switch contacts to the starter solenoid
The big current draw is the starter motor itself , which has a direct feed from the battery .
The relay would have two circuits " low power" , which closes the relay contacts and "high power" which feeds the solenoid
The low power circuit could be fed by removing the feed wire to the solenoid and connecting it to the relay . the other side of the low power relay would be earthed .[ The low power circuit would be protected by the existing fuse ???]
The high power circuit would be supplied by a new wire [ with an in line 20 amp fuse ? ] from the main power input terminal on the starter body.
The other side of this relay would be connected by a new wire to the solenoid input terminal.
I would appreciate comments before I weld myself to the underside of the car !
Cheers
Maxdog

[spider2081]

I think your thoughts are good.
I like to mount the relay on the drivers side fender well. In t he area of the charcoal canister there is a red wire with a single bullet connector in it. I separate the connector and re-route the end that comes for terminal 50 of the ignition switch up above the canister. Change the terminal to a female spade. This wire can power the relays coil and goes on terminal 85. The other coil terminal 86 connects to ground. Connect a new #12 red wire between relay terminal 87 and the starter solenoids spade connector. You can either remove the original short Red wire with the bullet terminal or leave it in the car unused.
Connect relay terminal 30 to the alternators output post through a 15-20 amp inline fuse. These terminals are for the commonly used Bosch style cube relays like the ones Fiat used. Note if your car happens to have an automatic transmission a starter relay was instaled as the "Park" safety switch.

[maxdog]

Hi
Thanks for the rapid response and the additional information on what to wire to where . On with the fur lined jock strap and off to work !
Cheers
Maxdog