Trailer isolator or just posi-tap?

[midlifeuturn]

For those of you that have wired your bikes for towing, is a trailer isolator needed or can you just use some posi-taps and tie into the wire harness? I plan on using all LED trailer lights (currently building trailer) so very little draw on the system. Do they make a "plug and play" trialer wire harness for the FJR?

Thanks

 

[SacramentoMike]

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Hyper lites provides posi-taps to draw off the brake/tail light for their units. Considering the draw from LED's, why would you need more than that?

(By the way, the HL kit I use has two 16-LED units that are powered by that tap and a very light wire.)

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[Auburn]

For those of you that have wired your bikes for towing, is a trailer isolator needed or can you just use some posi-taps and tie into the wire harness? I plan on using all LED trailer lights (currently building trailer) so very little draw on the system. Do they make a "plug and play" trialer wire harness for the FJR?

Thanks

The trailer isolator can use posi-taps to get the light signals (tail, brake, turn) but you will need to run a wire for power and ground to the battery or through a fuze block as these will provide the power to the isolator and trailer. If you use LED's you may need to get a different turn signal relay for your bike that is designed for LED loads (if you have LED's installed in the turn signals on the bike) or they might flash to fast.

I beleive Ahchui has the info for the relay

 

[midlifeuturn]

Yup, I understand that. What I don't understand is I see these trailer isolators mentioned a fair amount, but I'm not sure why they are needed or what the advantage is. The bike has the standard lights/bulbs and I don't think adding trailer LEDs is going to alter the flash rate. I've wired numerous trailers just not to a motorcycle.

 

[Auburn]

Yup, I understand that. What I don't understand is I see these trailer isolators mentioned a fair amount, but I'm not sure why they are needed or what the advantage is. The bike has the standard lights/bulbs and I don't think adding trailer LEDs is going to alter the flash rate. I've wired numerous trailers just not to a motorcycle.

You want to keep the two systems separate to protect your MC wiring system. It will prevent a ground or short in the trailer from affecting the bike's wiring. With standard bulbs on the bike, it will not alter teh flash rate. So that would be fine. It basically is a safety measure to protect the MC in the event you have a wiring failure on the trailer.

 

[Pepperell]

If you have an electronic cruise control, adding LED lighting to the brake light circuit can confuse the CC. An isolator should prevent this.

 

[FJRay]

I wired mine without the isolater using the adaptor to get it to a flat 4 pin hook up. Haven't had any issues yet. I soldered all the connections and sealed them. Don't like positaps.

 

[FJRGuy]

A little confused how one can direct wire a 5 wire system (tail, brake, left, right & ground) to a flat 4 trailer connector (brake, left/tail, right/tail & ground)??? If you are running separate tail and signal lights on the trailer (5 wire plug) then there should be little effect to the bike system but the isolator is cheap insurance. If you are running a 4 wire on the trailer, the converters that I've used (on cars, not my bike yet) are isolators as well.

Either way, Posi-Taps, when sized and installed correctly, are a clean, easy connection that do not damage the original wire and are easily removable.

 

[NightShine]

Bike to Trailer

As posted above, the electrical connection between your bike and tailer depends both on its wiring harness and on the degree of risk you're willing to accept. To be directly compatible with your bike's electrical system, the trailer will need to have turn signal lights that are separate from its brake lights, since the bike is a 5-wire system (ground, marker lights, left turn, right turn, brake lights). If your trailer is not equipped with separate turn signal lights, it typically has a 4-wire system where the brake lights double as turn signals (ground, marker, brake/left, brake/right). This will require you to wire in a "5-wire to 4-wire converter", which combines the vehicle's separate turn and brake signals into appropriate signals for the trailer's right and left brake lights. For example,

Trailer Isolation

This converter, if your trailer needs one, often does nothing to isolate your bike's lighting system from that of your trailer. And while it's not an uncommon arrangement to wire the connector on your bike directly into the bike's lighting harness, you are then powering the trailer's lights with the same wiring harness / relays / fuses driving your bike's lights. As others have pointed out, a fault in your trailer system can affect your bike's as well.

But a trailer isolator uses the bike's existing electrical system merely to drive the isolator's internal (mechanical or solid state) relays. The power actually driving the trailer's lights comes from a separately fused, direct connection to your bike's battery. At worst, trouble in the trailer's lighting system should only blow the isolator's separate fuse(s). Here's one commercial version:

You'll also see some devices out there that do double duty as both a 5-wire to 4-wire converter as well as an isolator, drawing power directly from the battery.

Murphy Happens

A couple of years ago I bought a small tent trailer for my FJR from a dealer up in Portland. It had a 5-wire wiring harness, so no converter was needed. But before heading up there, I did take the trouble to buy some relays, fuse holders and wire from my local electronics surplus store, and cobble together a home-made isolator. Potted the whole thing in epoxy, wired it into the tail light harness, and placed it under the passenger seat. Each output wire was over-engineered with its own fuse.

When I got up to Portland, the dealer had the trailer ready to go, except for the plug on its wiring harness. We compared notes on the pin-out of the connector on my bike (standard 5-wire), he wired the trailer side accordingly, and we hooked it up to the bike. Nothing! No trailer lights at all, but the bike's lights still worked fine. Took a closer look and almost all of the fuses in the isolator had blown! Seems he mis-wired the trailer's connector (off by one)...

Posi-Taps

That's what I used as well. Not as secure/reliable as s properly soldered joint, but much easier and cleaner to undo!