Weak signal from turn on lead

[anking33]

I am trying to connect my cooling fan for my amps. I am using a relay to turn the fan on using the turn on lead. The one that turns on the amps. When the relay is wired correctly, the fan truns on, but then one of the amps doesn't turn on. When I disconnect the fan, the amp truns back on. I think that the signal is not strong enough to turn on all the components. Does anyone know how to fix this, a signal amp, or different wiring suggestion. It makes no sense, because I wiried it this way in another car and it worked fine. Thank you

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[ParkRat 10+ year member]

It sounds like your fan interrupts the signal to the amp. It doesn't take much at all to turn on the amp so I don't think that is the case. My suggestion is to connect a wire from the turn on led to the amp before the fans and not after. I'm not sure how you have it all connected.

 

[anking33]

In response to the questions and suggestions:

The amps and fans are wired as such;

1. The lead wire goes from the head unit to the rear of the car.

2. The lead splits in order to connect to the two amps and the fan relay.

3. Because the remote lead is a circuit, some of the voltage from the turn-on lead goes to each of the amps. The amps are internally wired to complete the circuit, i.e connect to ground.

4. The relay most also complete the circuit, so it is also wired to ground.

5. Thus, it doesn't matter which amp or relay is connected first(in a physical sense) because they all share the same potential(voltage) which is the voltage of the turn-on lead.

I know this to be true, I tried every arrangement possible, even running the remote lead in series with the two amps.

Plus, for those of you with your wheels turning, I ran a range of resistors in series with the relay, incase the relay was shorting the amps. At best the amp power light would flicker on and off and the fan would run.

Everything points to the remote lead not having enough power, does anyone know a quick fix or alternate wiring config

 

[anking33]

This is going to seems stupid as I am answer my own questions that I presented to the forum. But in case anyone cared. I thought I would share my findings.

The best way to wire you fans and amps is as such;

1. Run turn-on lead to input of relay. Don't run the turn-on lead to anything else.

2. Run relay output to ground.

3. Run 12V power wire to the input of the switched portion of the relay. Your big power cable for your amps is a good spot to connect this wire.

4. The switched output portion of the relay should be connected to your amps turn-on terminal as well as the positive lead of the fan.

The head unit activates the relay switch, then power is provided to the amps and fan.

 

[ParkRat 10+ year member]

So is it fixed //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[helotaxi 5,000+ posts]

The best way to wire you fans and amps is as such;
1. Run turn-on lead to input of relay. Don't run the turn-on lead to anything else.

2. Run relay output to ground.

3. Run 12V power wire to the input of the switched portion of the relay. Your big power cable for your amps is a good spot to connect this wire.

4. The switched output portion of the relay should be connected to your amps turn-on terminal as well as the positive lead of the fan.

The head unit activates the relay switch, then power is provided to the amps and fan.

Basically you were drawing too much current from the HU lead and it's voltage was dropping just enough that it was not enough to turn on the one amp. Some amps are very sensitive when it comes to turn on voltage and some HUs cannot provide much current at all through their turn on lead before the voltage starts to drop. This is why it is always advisable to use a relay to switch more than one amp and any other components on that you want running with the HU. Good to see that you figured it out on your own.

 

[fugit 10+ year member]

I know this is an old thread, but I'm having the same problem and I'm not sure I understand. The relay goes before everything? If you have an electronic crossover and multiple amps would the relay go between the HU and the crossover?

 

[sumone 10+ year member]

basically, he's just saying go from

HU->remote wire->relay->electrical devices

basically, the only thing the remote wire should connect to is the relay and not anything else. I've got two amps, two 120mmx120mm fans, and an EQ hooked up. Nothing comes on when I just have everything running off the remote. Gonna pick up a relay up today and then just have

HU->remote wire->EQ->remote wire ran to the trunk->relay->amps & fans

since the EQ is in the glove box