What all oughtta be on relays?

[maytag]

[TX82FIAT]

Wow, this sounds like a great idea. I'd like to see it all when done. What Gauge wire will you run from the alternator to your relay union at the glove box? Do you have a stereo? Will you need additional fuses?

[maytag]

[spider2081]

I am a believer in relays. The main reason is to keep the higher current loads out of the ignition switch. This extends the life of the ignition switch. In my case the start position of my ignition switch was faulty. Installing a relay in the starter solenoid circuit cured the problem. The wipers really work much better with a relay. I chose to install mine under the dash in the wire that feeds the hi-lo speed switch.
The cooling fan power does not pass through the ignition switch. That is how it runs after the car is shut off. You might not need a relay in that circuit.

[Fiat88]

I am a believer in relays. The main reason is to keep the higher current loads out of the ignition switch. This extends the life of the ignition switch. In my case the start position of my ignition switch was faulty. Installing a relay in the starter solenoid circuit cured the problem. The wipers really work much better with a relay. I chose to install mine under the dash in the wire that feeds the hi-lo speed switch.
The cooling fan power does not pass through the ignition switch. That is how it runs after the car is shut off. You might not need a relay in that circuit.

The cooling fan on my '79 only runs if the ignition switch is turned on. What year is your car?

[spider2081]

My car is a 1981. I don't have a wire diagram for a 79 but I would think your cars fan would run when ever the temp switch in the radiator turns on. MAybe someone more familiar than I with a 79 could help here.

[DocGraphics]

My '78 fan will keep running after the ignition is turned off

[RRoller123]

Power to the radiator fan is always hot, doesn't need to have the ignition on, per my 1980 schematic. Fed by a Light Blue wire from Fuse position 10. I would assume that it has been modified somehow if it won't run unless the key is on?

[124JOE]

matag
the horn is already on a relay

[124ADDHE]

I would only relay the high load items, pretty much the headlights, the horn; the rest of the wiring for your car is then much more able to provide full voltage to the other circuits; relays fail and are a pita to change roadside in the evening.

I have my rad fan wired up to the alternator and the ground is switched by the radiator thermoswitch; i am adding a relay to switch the ground open from the drivers seat for those days in the summer when you hit traffic and know you are going to need the fan, mine doesnt come on till 210deg or so.

If lubed up well the wipers work great (other than parking, but we all know that trick), mine are actually used most often on low speed.

user some electrical connector conditioner or even diaelectric grease after you clean your grounds to the extreme, this is the other half of the battle OR use a grounding bus like in that other post (cool idear).

I love my spider so much more now that the electrics are working better than original ever had them, now my spider is easily my most reliable car; not saying much with a jag and range rover in the garage though

[maytag]

[majicwrench]

I'm with ADDHA, no point putting relays everywhere, just that much more mess and things to go wrong. The factory wiring, despite what you read a lot on this board, is well designed and works well if it is all clean and tight.
Keith

[maytag]

[RRoller123]

Maytag: I am starting my new power distribution scheme today myself. I plan on mounting a box on thefender wall if I can find room, to house the relays and power distribution. Bringing fresh power up from the Alt to a distribution buss, then send it out through relays and fresh connectons to the headlights, fog lights, wipers etc. I agree in general that only the large loads really profit from the relays from an ignition switch standpoint. If we can offload the ign switch from a couple of heavy loads it seems like that should help a lot?

[majicwrench]

Yeah, those Fiat Gods were something else...

But really, putting relays everywhere adds lots of complexity and adds lots more stuff to go wrong. And a relay is a switching device, just like a switch, so you are not eliminating a switching device, just adding a different one.
Heck it's your car, have fun with it. I'll continue to bow down to those who created from dust what we know as FIAT.
Keith