Ignition Switch Starter Relay

[RRoller123]

Just to be sure.... It is the RED wire coming from the Ignition Switch and going to the Starter Solenoid that we want to use as the trigger in the Starter Relay being added, yes? It goes through C31 (first white block connector just downstream of the Ignition Switch), then through C6 (bullet connector behind Alternator), then connects to Starter Solenoid at C50.

So I am assuming that I use the RED from the back of the Ignition Switch to trigger the relay, but pulled AFTER C31, since the RED/BLK that branches at C31 is needed to run to the FI Relay Set? (Or maybe just pull the RED trigger at C6?)

And pull the Relay power for the Starter Solenoid either directly off the back of the Alternator (at B+), or at point "30" on the schematic?

The RED/BLK at C6 does not exist on the FI cars. Nor does the BLK at C17, unless one has power windows. C17 could therefore be soldered permanently.

[spider2081]

C17 is not usually located in a place that is easy to access for soldering or crimping. If it is not discolored from over heating I would leave it be.
I mount the starter Bosch cube type relay on the driver side fender well. Its exact position is determined on the length of wire at C6 coming from the ignition switch. I disconnect C6 and pull the end from the ignition switch back up toward the top of fender well. Sometimes this requires cutting off some of the black wire bundle wrapping material. Then cut off the bullet connector and crimp on the female spade connector so the wire can be put on terminal 85 of the new cube relay. Terminal 86 connects to ground. Cube relay terminal 30 connects to alternator output B+ terminal through a 25 amp fuse and terminal 87 gets a new #12 wire that connects to the starter terminal spade connection.

[RRoller123]

Excellent, thanks, that helps tremendously.

Pete

[bjbrown]

I'm just about at the place where I can install relays to reduce the load on the ignition switch on my 1980 Fiat Spider EFI with power windows/manual trans. Question: besides the starter, what other components should be fitted with relays? I already have bought a kit to put relays on the headlight circuits. Has anyone written a FAQ or tech sheet on this process? Is there a wiring diagram showing how the starter relay should be configured into the original harness? Is there a place where ALL these additional relay modules be fitted to the car (inner fender inside the engine compartment?)? Someone have photos of where they've positioned the components and routed wires? Recommendations on fuse sizes for the various circuits?j

[zachmac]

bjbrown,

Other major component to consider for relay is the wipers. Not usually running but a big draw when needed and work much better with direct power form the battery. You can overdo the whole relay thing but in general any time you take a big current draw off the ignition switch in exchange for a small trigger current you are doing a good thing.

[spider2081]

Here is a photo of a fuse panel and relays mounted in my 1981 Spider. The relays are for the headlights, Starter, coolant fan and the driving lights I installed under my bumper. I have a relay for the windshield wipers also. It is mounted above the ignition switch. For that relay I disconnect the input wire to the speed switch and us it to control a cube relay. The from one of the fuses in photo run a #12 to the relay to power the wipers. It did increase the wiper speed.

[bjbrown]

Spider2081, looks like you've mounted the relays and associated fuse block on the inner fender wall in the engine compartment above and behind the charcoal canister, right? How/where did you rout the cables from the dash harness?

[spider2081]

How/where did you rout the cables from the dash harness?

I pick up the coolant fan wires at their connectors near the radiator.
I disconnect the headlight bucket 2 pin connector on the driver side and use half from the passenger compartment to operate the relays and connect both buckets to the relays. I use one relay for both hi beams and one relay for both lo beams
I disconnect the single bullet connector C6 behind the alternator and use the side from the ignition switch to operate the starter relay. Then I run a new wire from the relay to the starter solenoid eliminating C6.
I run a power wire from the new fuse panel to the area of the ignition switch and mount the wiper relay above and behind the ignition switch. I remove the gray/black wire from the wiper speed switch and use it to control the relay and make a new wire to run from the relay to the wiper speed switch.

Hope this helps