Stock Reverse light circuit sensitivity?

[parb]

I tapped into the reverse light circuit for my leitner chase lights. I use a relay to protect the circuit from high current.

I've noticed that both the reverse lights and my additional lights come on but after a second or two the reverse lights come off. I have both my wolfbox and my chase lights tapped into the same circuit for the reverse light detection.

My theory is that the control box for the reverse lights is measuring current draw and is turning off the reverse lights due to to high current consumption. A protection mechanism. It is speculation though based on sewing this behavior on the headlight circuit when current went up and the display threw an error message.

I think the relay consumes 160mA and it's just about the only thing I can think of that explains the behavior. I'm going to remove the chase light relay control to verify this.

There is nothing else wonky going on? Nothing screwy like the reverse lights using pwm signaling or something like that?

Have people been successful hooking up relays to lights in our cars, or is it just me getting challenged?

I'm going to try a flyback diode across the coil to see if it's coil noise making the circuit misbehave.
If that doesn't work then I think I'll have to try to a pfet transistor to get a high impedance control signal for the relay to reducw the current draw on the brake light circuit.

I have yet to see automotive ssr relays but maybe I just haven't looked enough?

Or maybe just tap into the trailer brake circuit, it should be designed for higher current applications.

Anyone else been playing with lights and relays? Found anything unusual?

 

[RyanT]

Hey Parb,

How have you gotten on with this?

 

[parb]

Thanks for pinging me. It's user error.
I wired the additional lights directly into the reverse light circuit and the extra 1A of load was too high. Wired in the relay correctly with diodes to prevent reverse current to the backup lights in case I use the switch.

It's all good right now.
I can make a diagram for how to wire if it's helpful.
The backup light circuit definitely needs a relay, higher current results in the lights working for a few sconds and then turns off.

Hot tip, test for 10-15 seconds or so. I tested for just a few seconds and that was a mistake.

 

[RyanT]

That's good to know, thanks for sharing!

 

[cn11]

Thanks for pinging me. It's user error.
I wired the additional lights directly into the reverse light circuit and the extra 1A of load was too high. Wired in the relay correctly with diodes to prevent reverse current to the backup lights in case I use the switch.

It's all good right now.
I can make a diagram for how to wire if it's helpful.
The backup light circuit definitely needs a relay, higher current results in the lights working for a few sconds and then turns off.

Hot tip, test for 10-15 seconds or so. I tested for just a few seconds and that was a mistake.

Did you ever have a chance to do a diagram wired mine up this afternoon and having the same issue.
I wired based off of this from baja designs and still having the few seconds on and then all off.
On with the switch no issues...
I did notice that on my relay the 85 and 86 spots are flopped.
So currently my ground is in 85 and wire to switch 86. Ran out of time to swap and test that...

 

[Adamc1303]

I wired mine by getting power directly from the fuse box under the rear passenger seat. I then only used the reverse light wire to send a signal to a relay. That way the light has power but the relay only turns it on when it senses the reverse signal. It works perfectly fine that way.

 

[parb]

Did you ever have a chance to do a diagram wired mine up this afternoon and having the same issue.
I wired based off of this from baja designs and still having the few seconds on and then all off.
On with the switch no issues...
I did notice that on my relay the 85 and 86 spots are flopped.
So currently my ground is in 85 and wire to switch 86. Ran out of time to swap and test that...

I'll draw it up this afternoon. Stay tuned

 

[parb]

I'm sorry for my bad handwriting. I had nothing to write with except my tablet.

Attached are two diagrams. The one in black shows how to wire the Baja S2 to the reverse light circuit with a relay. I took 12 from the power block in the rear wheel well on the right hand side, on the positive side for the big 500A relay. Make sure you use a fuse.

The blue circuit shows how to wire in one of the int switches. I took the wire from the driver's side fotwell. This lets you turn on the reverse light with one of the int switches as well as making it come on automatically when the reverse lights are on. This circuit requires two schottky diodes. I used 15SQ045, it's a 15A diode so a bit of overkill. It protects the reverse lights from being back fed by the int switch. It also prevents the int switch from being back fed by the reverse lights. This is how I wired up my Grenadier. The schottky diodes are available on Amazon for $5 for a 20 pack. The band on the diode is the pointy end with the "wall" symbol on the diagram. It only lets power flow in the direction of the arrow. Schottky diodes loose less power than regular diodes and for this I thought they were a better choice. They aren't very sensitive to anything. I wired them in with a soldering iron directly to the wire and covered it in shrink tubing.

It doesnt matter if you have a 4 or 5 pin relay, wire them up according to the diagram, you have two 87 pins one is normally open and one is normally closed, you may need to move the connection to the lights between the 87 pin in a 5 pin relay so it's of 5 when the reverse lights are off and the int switch is off. That's the normally open "NO" pin.