Electric Relay Advice

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jonn6464

jonn6464

1970 Duster
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Hey FABO electrical gurus, I'm looking for some guidance on relays. Specifically, what to use them for.

As I'm getting closer to finishing the wiring on my 70 Duster, I'm thinking about relays. But, I don't really know where to use them.

At this point, I know I'll use relays for the headlights and electric radiator fans, but I'm wondering about some of the other modifications that I've made.

So, would you recommend relays for the following...
- electric trunk release
- aftermarket stereo system
- push button start
- aftermarket A/C
- back up camera

Are there any other components that would benefit from having a relay installed?

Thanks for any replies
 
- electric trunk release............no, pretty low current
- aftermarket stereo system........likely not, depending on how it's wired. Most stereos are "hot" and the switches in the stereo take care of all that
- push button start.....either use your stock start relay, or replace it with a Bosch style relay
- aftermarket A/C....No it should have it's own controls
- back up camera...No, low current

Main stuff:

Headlights, a relay for high and a relay for low beams. The light switch goes to the dimmer switch. The dimmer switch keys on one or the other, hi or lo beam relay

Fuel pump, EFI if used

Use at least one relay, triggered by the key "run" circuit, to power the underhood loads, ignition, VR/ alternator field and whatever else is no the "run" circuit

You might want to do the same for the accessory feed.........use the key switch to trigger a heavy relay, and the relay will power "on" the accessory buss.
 
67Dart273 said:
- electric trunk release............no, pretty low current
- aftermarket stereo system........likely not, depending on how it's wired. Most stereos are "hot" and the switches in the stereo take care of all that
- push button start.....either use your stock start relay, or replace it with a Bosch style relay
- aftermarket A/C....No it should have it's own controls
- back up camera...No, low current

Main stuff:

Headlights, a relay for high and a relay for low beams. The light switch goes to the dimmer switch. The dimmer switch keys on one or the other, hi or lo beam relay

Fuel pump, EFI if used

Use at least one relay, triggered by the key "run" circuit, to power the underhood loads, ignition, VR/ alternator field and whatever else is no the "run" circuit

You might want to do the same for the accessory feed.........use the key switch to trigger a heavy relay, and the relay will power "on" the accessory buss.
Click to expand...
Great, thanks for this info.

I am running a Holley Sniper with a Tanks Inc in tank fuel pump. Not installed yet, so I'll have to see what's included in the kit.
 
clemintine has a boatload of experience starting from scratch with wiring the Sniper. He's also one hell of a nice guy. I recommend you PM him. Calling "clementine", are you on this net?
 
Hello jonn6464
Just as a note Flosser 2268 Relays are of exceptional quality and include a Diode across the Coil.
You can find them on E Bay as a pack of 2 for $14.00 with free shipping.
Or can be obtained from local auto parts stores.
Hope this helps.
Happy Mopar :)
Arron.
 
Arron tate said:
Hello jonn6464
Just as a note Flosser 2268 Relays are of exceptional quality and include a Diode across the Coil.
You can find them on E Bay as a pack of 2 for $14.00 with free shipping.
Or can be obtained from local auto parts stores.
Hope this helps.
Happy Mopar :)
Arron.
Click to expand...
On a side note, pay ATTENTION to coil polarity with diodes. Either some relays have diodes wired backwards, or some of the info on the internet is wrong. If you connect them backwards in a simple circuit, you will blow up the diode, but if you use them on the ground leg switched outputs on an EFI for example, you might blow up the switching devices in the EFI module.

Those diodes are intended to reduce "inductive kick" from the relay coil, "spike supressors."
 
Arron tate said:
Hello jonn6464
Just as a note Flosser 2268 Relays are of exceptional quality and include a Diode across the Coil.
You can find them on E Bay as a pack of 2 for $14.00 with free shipping.
Or can be obtained from local auto parts stores.
Hope this helps.
Happy Mopar :)
Arron.
Click to expand...
Cool, great tip. Thanks
 
Only relay that i put on that hasn't been mentioned was one back by the fuel pump. The sniper wiring has one, but it's up front of the car. Having my battery in the trunk i felt like putting it closer to the pump was better. I didn't remove the sniper one.... just added another... might be incorrect but the fuel pump comes on.

As far as triggering the fans, they are ground triggered. So the light blue and light green (blue is speed #1, green speed #2....2 speed fan ya) go to the ground side of the relay. (85?)
 
I knew you have a boatload of knowledge, and had the answer. Thank You, David.
 
clementine said:
Only relay that i put on that hasn't been mentioned was one back by the fuel pump. The sniper wiring has one, but it's up front of the car. Having my battery in the trunk i felt like putting it closer to the pump was better. I didn't remove the sniper one.... just added another... might be incorrect but the fuel pump comes on.

As far as triggering the fans, they are ground triggered. So the light blue and light green (blue is speed #1, green speed #2....2 speed fan ya) go to the ground side of the relay. (85?)
Click to expand...
The light blue and light green wires you mention for the fans, are those the Sniper wires?
 
jonn6464 said:
The light blue and light green wires you mention for the fans, are those the Sniper wires?
Click to expand...
Yes. They come from the 10 pin connector and are "output' wires. So the 30/87/86 on the relay go to fan/fused 12V/switched 12V respectively, and then the '85' goes to the light blue on that 10 pin, if you have dual fans or 2 speed, run another relay for the green wire setup as well. You will set at what temp those turn on and off when you start car and have access to the 'wizard' setup/monitor thingy. A lot of the 10 pin wires I did not use. I think the only other one I used was the white one that runs to the ignition box.
 
clementine said:
Yes. They come from the 10 pin connector and are "output' wires. So the 30/87/86 on the relay go to fan/fused 12V/switched 12V respectively, and then the '85' goes to the light blue on that 10 pin, if you have dual fans or 2 speed, run another relay for the green wire setup as well. You will set at what temp those turn on and off when you start car and have access to the 'wizard' setup/monitor thingy. A lot of the 10 pin wires I did not use. I think the only other one I used was the white one that runs to the ignition box.
Click to expand...
Got, it. Thank you for the detailed replies!
 
[QUOTE="67Dart273,
Those diodes are intended to reduce "inductive kick" from the relay coil, "spike supressors."[/QUOTE]

Hello 67Dart273,
Great explanation for Diodes on relays to control inductive kick (Flyback Voltage)
Also a relay can have an added resistance across the coil (as depicted in pix) in addition to the natural coil resistance.
Depending on the application they may use a Zener Diode instead of a traditional type Diode to customize the specific application.
There are numerous types Transient Voltage Suppressors (TVS) and MOV's that can be used.
Happy Mopar:)
Arron.
Flosser 2268 Forabodies Only..jpg
 
70dart340 said:
I knew you have a boatload of knowledge, and had the answer. Thank You, David.
Click to expand...
Its kind of trial and error. Im experiencing a 'no start' as of this moment, so not exactly a pro. I appreciate the moral support though.
 
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