5.SLO

How to Wire a Relay for Trans Brake???

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Can anyone here advise how to wire up a relay between my trans brake and trans brake button?  

Using a 4 prong 30A relay, how would it be wired?  There are 2 wires coming from the trans brake button and 2 wires coming from the trans brake, but I don't know what would go where. 

 

Sorry for the stupid question... I'm electrically retarded. 

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Got a diagram from the maker of the trans brake?

Dummy info:  4 terminals of a relay TYPICALLY have two small terminals and two much larger terminals.  The small terminals are the low current side which your thumb switch controls.  So, typically a fused hot in run wire goes to your switch, the wire from your switch goes to the relay low current side.  The other low current terminal goes to ground.  Thus the switch turns on the relay.

The high current side would be a fused hot in run wire to the relay high current terminal, then from the other high current terminal the wire goes to your trans brake.....

Edit:  ....and the other transbrake wire is grounded.

 

Edited by Ashley P

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Unless you are trying to run this in conjunction with an efi box function or you have a really small switch, you don't need a relay.  Most tb solenoids don't pull 5 amps or less.

the relay will actually make the transbrake react slower

Ashley P likes this

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Depends on your TB solenoid. Some are low amp, some are high. If it's small, then it's low amp and doesn't need a relay. If it's larger (1" or larger) then it'll need a relay. For the TB, you need to decide if you want to trigger it with 12v+ or 12v-.

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1 hour ago, Mike said:

Unless you are trying to run this in conjunction with an efi box function or you have a really small switch, you don't need a relay.  Most tb solenoids don't pull 5 amps or less.

the relay will actually make the transbrake react slower

So run it through a transistor.  lol

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its better to activate 12v+ versus 12v-, Ive seen issues where a chaffed wire hit ground and activated erroneously causing problems.

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Check with the manufacturer of your transbrake and find out the amp rating of the solenoid.  Do the same for your switch.  If the switch is good for as much as the solenoid, no relay is needed and fuse it accordingly.  I also like to tie the reverse lights in with the + on the solenoid to help the brake release faster.

 

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Dumb question, how does tying in the reverse light help it release faster?  Limiting the current to the solenoid?  Helps kill the flyback?

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Awesome!  Thanks for the reply's!  It fried two of the Hurst ball's that have the button on top, so I figure it's throwing more than 5A..... or it could be that the Hurst units are junk! 

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On 9/8/2017 at 11:01 AM, Disney said:

What trans? C4? If so, i've only seen high amp solenoids on them. You'll need a relay.

Yeah, it's a C4. I ended up wiring an in-line 10A fuse as a temp fix, and so far, no issues. 

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