rivermobster
Well-known member
- May 5, 2021
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Low pressure oil pressure switch would fix that.
AC Delco makes one that can be used with power or ground.
I have the part number somewhere if anyone needs it. Google works too.
Automotive relays
- Thread starter EastMT
- Start date
Low pressure oil pressure switch would fix that.
AC Delco makes one that can be used with power or ground.
I have the part number somewhere if anyone needs it. Google works too.
- Thread starter
- #22
EastMT
Well-known member
- Jul 21, 2022
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I didn’t want to taint my request for what others used but I have two hella 40 amp relays that get too hot to touch when powering a 20 amp Spal brushless fan. A 30 amp Floser relay powering the same fan is cool to the touch. The MSD solid state is still high on my list.
I put mine in a mostly sealed up box with the ecu works great keepin the sand off them.I did a swap for a friend and when they did some work they removed the box and decided to put the relays under the rear seat where they are exposed to the elements and always fail.
Rockwood
Well-known member
- May 5, 2021
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Wouldn’t that need to feed a relay?
Sandkist
Well-known member
- May 6, 2021
- 2,751
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Either way. Ignition on provides a 12 volt signal to the ECM which in turn operates a fuel pump relay (or should lol). Can also be configured to have a fuel pump output that is isolated from the. ECM.
Travelah
Member
- May 7, 2021
- 33
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Switch pros have trigger inputs that can be set up as high or low. The 9100 has 2 and the force-12 has 3. I usually set up fans and fuel pump on the triggers. As for relays I use the sealed relays from prowire. I saw some info somewhere that said the brushless fans are hard on relays. Generally, those just get fused power, a ground, and pwm signal to operate. Bussman makes a 70amp relay as well and it has two fuses built in (one for relay and one for accessory). They can be bussed with a copper bar if using multiple.
www.prowireusa.com
Sealed Relay Kit
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Rockwood
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- May 5, 2021
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Dammit, now I need to buy a Switchpros…
rivermobster
Well-known member
- May 5, 2021
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Nope. It could interrupt, or provide continuity, for any circuit one wanted. Fuel or ignition.
If it's a high draw/amperage circuit, a relay would definitely be preferable.
rivermobster
Well-known member
- May 5, 2021
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Ya have to Also remember...
A relay doesn't have to be on the positive side of a circuit, nor does it have to be actuated by a positive signal!
If I'm wiring some completely from scratch, I'd rather see a relay ground actuated.
Why?
The less positive wires overall that way, makes for far less chance of dead shorts.
If a ground wire shorts to ground, so what? The circuit just stays on.
We all know what happens when a positive wire shorts to ground, so eliminating those opportunities, makes for a safer vehicle.
A relay doesn't have to be on the positive side of a circuit, nor does it have to be actuated by a positive signal!
If I'm wiring some completely from scratch, I'd rather see a relay ground actuated.
Why?
The less positive wires overall that way, makes for far less chance of dead shorts.
If a ground wire shorts to ground, so what? The circuit just stays on.
We all know what happens when a positive wire shorts to ground, so eliminating those opportunities, makes for a safer vehicle.
Kraut_n_Rice
Site Sponsor
- May 9, 2021
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Using a ground to trigger a relay can lessen overall wiring by jumping the input (if positive) to the coil. Then each relay would only have 3 wires going to it.
rivermobster
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- May 5, 2021
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Rockwood
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- May 5, 2021
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@rivermobster Bonus is you can more easily land all of those grounds on a daisy chain back to the battery to reduce noise.
rivermobster
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- May 5, 2021
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Yes sir. Or, just ground to the chassis. Much less wiring that way.
Lots of ways to skin this cat.
r3meyer
Active member
- May 5, 2021
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Fuel pump is hooked up to the MSD sold state relay. Holley controls the MSD Fan#1, Fan#2, and Fuel Pump via negative ground triggers. Holley primes fuel pump for 5 seconds on key on, or if you're cranking. If the engine stops for any reason so does the Fuel pump.
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J Alper
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- Apr 30, 2021
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Bobalos
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- May 5, 2021
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@J Alpe. The link does not work... Ths one??
www.prowireusa.com
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