'75 280Z Headlight Relay Upgrade

[TomoHawk]

That looks like something NASA would use on a space vehicle.  What are the long gray things?

[Patcon]

The long gray fuse looking things are circuit breakers. They trip when overloaded and reset when cool. I used one on my Suburban when we couldn't find a short. When it starts tripping a lot it becomes easier to find.

[Patcon]

H-M

How much do those cost? I looked around a little bit but couldn't find them for sale...

[Hodgimus-maximus]

Waytek sells the the box for about $30 depending on which one you get and its features. But you have to buy a bunch of other bits and bobs to set it up so I will end up costing around $50 to $100 once it's all tallied up. 

 

http://www.waytekwire.com/products?pSearch=RTMR

[Patcon]

That's really not so bad

[tamo3]

Just update schematic based on Captain's starter relay addition using TOYOTA Corolla Relay&Fuse box.

 

 

I can't figure out which pin is 85, 86 on TOYOTA's relay 90987.

 

Does it matter?

 

[SteveJ]

It only matters if the relay has a diode.

[Captain Obvious]

Hi Tamo,

 

As SteveJ mentioned above, the polarity across the coil winding only matters if there's a built in diode inside the relay in parallel with the coil winding. I can't attest to the contents of all of the relays in that form factor, but I can tell you that the ones I messed with did not have a diode inside and the coil polarity did not matter.

 

Also, on your sketch showing the starter relay, I think you swapped the C4 and C7 designations and the destination labels for those connections. I think what you have labeled as C4 "To fusebox" is actually C7, and vice versa.

 

And one last thing... If you're doing an internally regulated alternator upgrade at the same time as the starter relay it is convenient because the original external regulator already has some of the connections necessary for the starter relay. In other words, the external regulator already has "always hot" and "ground" connections that can be re-purposed to power the starter relay system once they are no longer needed for the external regulator system.

 

 

[TomoHawk]

OK,  but for a certain form-factor, isn't the pin-out the same for the different manufacturers?

Edited June 19, 2015 by TomoHawk

[EuroDat]

Nice work Tamo. Can you open the dimmer relay without irreversibly damaging it?

If you could cut the resistance, it would also be a servicable relay. Maybe foglights or some other high current drawing system.

[Captain Obvious]

The form factor and pin-out should be the same for any manufacturer, but I can't attest to the inclusion of a diode inside to squelch the inductive kickback. Sometimes an internal diode available as an option from the manufacturer. In other words, sometimes you can buy the exact same relay in two versions... with or without an internal diode.

 

[Captain Obvious]

Chas, Why do you think it would be necessary to open the "dimmer" relay to cut the resistance? That resistor is in parallel across the coil windings to limit the inductive kickback voltage and compared to the coil resistance, I bet it's a relatively high resistance. Like maybe an order of magnitude?

 

It would "waste" a small amount of power when the relay coil is energized and be completely innocuous when the coil is off. I don't understand why you cant just leave the resistor alone and use it for it's intended purpose?