I'm setting up the wideband on my truck with the EBL and 7747 and need to know if the the shift light output can handle continuosly driving one of the factory relays? I want to use it because I checked the fuel pump relay and it is turned on while cranking. I plan on using the shift light output and setting the rpm low like 6-700 so it only turns on once the engine is actually running. It should work the way I want it to shouldn't it? Thanks

 

assuming the starter can spin up that high, possibly.

the output drivers are probably capable of 1 amp continuously, though if you really want to be safe, keep it at half an amp or less.

most automotive realys seem to draw between around .2 amps, so i'd say it will be more than fine.

keep in mind you may have an oil pressure switch activating your fuel pump. those are the factory contiengency method if the relay fails and will power the pump when above ~3 or 4PSI.

 

That's my point, I don't want the wideband on while cranking, that's why I'll set the rpm to 6-700. I don't know what is turning it on but the fuel pump relay is definitely on while cranking, that's why I want to use the shift light output. The EBL documentation says like 1/4 amp max for the output and I'm using a factory relay, I just wasn't sure about having it continuously on while the engine is running.

 

Typically automotive relays use between 50-100mA while active at 12VDC, measure the resistance across the coil of the stock relay and that will tell you how much current it can use. (Current=Voltage/Resistance).

 

It can handle a relay that is always on. Be sure to get the coil polarity correct, there is an anti-kick back diode in parallel with it.

The TCC output, which can also be used as the shift light output, has the driver doubled up.

RBob.

 

Thanks, that's exactly what I needed to know. I would use the TCC output but it's already in use because of the 700r-4.