2008 Sienna from Scratch to Tow Ready...with a little help please?

[tcp]

I would suspect only two would normally be required but I assume the modulite will require an extra (or it can be grounded at the same point as the 7 way connector ground wire that runs out to the trailer plug).

One near the brake controller. This is a reference ground and will not flow any real current. The trailer brake current flows through the ground return on the 7 blade connector.

One from the 7 blade connector that comes from the socket outside. Make sure this a GOOD Ground as the brake current will flow through it along with light current and charging current clear some area to bare metal and bolt the wire to it with a ring terminal. The better this ground is, the more efficient everything else is.

One from the modulite unit. This is really just a reference ground again as the light current will return through the 7 blade connector. using the same spot as the GOOD ground from the 7 blade connector would be a smart option.

so for my the entire wiring system...how many ground wires will I need, where will they run from and to, and what gauge should they be?

[brian_bp]

The Sienna's own electrical system - following typical automotive practice - uses some carefully selected and prepared points to connect to the body, and the steel of the body to conduct back to the battery. Added wiring can use the body through as carefully managed points - perhaps the very same points which Toyota uses... or it can use separate wires straight to the battery's negative terminal. I put in the wires.

Remember that paint and rust make for lousy connections, and that the body is painted and where you break the paint film the steel rusts.

[johnson]

So if I run 8 gauge wire with 30amp cb, and 30 amp relay back to the 7-pole for 12V charging power...can I just tap into that same 8 gauge line to power the Modulite?

[brian_bp]

From an electrical safety point of view, I see no problem with sharing a properly protected (right-sized breaker) circuit among as many loads as desired, provided that their total demand is not excessive for the circuit.

On the other hand, from a vehicle safety point of view, I would not want my trailer lights to stop working because of any electrical fault associated with the trailer battery and its charging supply. When the charging circuit's breaker opens because of an overload, anything sharing that power supply would stop working. I would, instead, run a separate circuit for the Modulite, with appropriately sized wire and breaker as discussed earlier.

Similarly, I would not want my trailer brakes to become non-functional due to a breaker popping in response to a short in a trailer lamp. The end result is three independent circuits, for lights, brakes, and charging. In my case, the trailer lights are powered from the Sienna's light circuits (I don't have a powered converter such as a Modulite), so I only have two circuits (brakes and charging).

[johnson]

Thanks everyone for your quick and informative replies. Everything should be ready to go...with the exception of caulking the grommets in the rear well. I'll be picking up my camper tomorrow afternoon so hopefully its all installed correctly [fingers crossed].

[johnson]

Well I made it back in one piece. No big problems with the voyage run. A few things though that I would like to ask about. With the Reese Mini 350, is there a trick to getting the bars into place without such a struggle? The guy at the dealership had a heck of time getting them in place, and when I got back and tried to unhook I had the same issue.
Before leaving the dealership lot I tried to complete the Prodigy setup. It seemed like the controller was not "recognizing" that the camper was hooked up. It was giving the ". ." on the display which according to the manual means there's power to the controller but the trailer is not hooked up. If I would go back and unplug the 7-pole and plug back in, it would recognize it for about 2 minutes and then go back to ". ." Anyway after trying that 4 times it gave me the ".c." display and worked the entire 100 mile trip home. Any ideas?
Also, at speeds between 20-40mph, if I went over a little bump, it seemed like the van was bouncing quite a bit...almost like there was someone jumping on the back bumper. At highway speeds the bouncing wasn't noticeable at all. Could this be a product of the PSI in the Airlift bags? I remember reading somewhere about the PSI for the Airlift bags when towing...but it escapes me right now.

[brian_bp]

If the spring bars require a lot of force to lift into place, the head may be tilted too far back, pivoting the bars down too far, meaning they need to be lifted too much (and are applying too much force). One Unusual feature of that hitch (if I'm picturing the right one) is that the bars ride on top of the trailer tongue; with the normal hanging-from-chains setup the chains attach to lift brackets, which are used with a lever to make it easier to engage them.

A common trick - which I suspect people usually use because they are applying too much force with their spring bars - is to raise the trailer tongue and hitch by cranking the tongue jack up after coupling, which makes the angle of the spring bars higher so they are easier to engage.

The electrical connection situation sounds like it might be contacts in the plug or socket which need to be connected and disconnected a few times to scrape the contact areas for better contact.

The minimum pressure for the nearly identical Coil-Rite bags is 5 psi (to keep then seated in the coils), with a 30 psi (I think) maximum. They should be adjusted to bring the suspension back up near the unloaded height, but definitely not higher than that and not to exceed that maximum rated pressure.

[johnson]

Thanks brian_bp,
Now that I hear the explanations it makes sense. When I was unhooking I uncoupled the hitch from the ball first and then tried to get the bars off. I finally figured that the angles just weren't right and re-coupled and kept cranking the wheel higher and higher til the bars came free. So now it makes sense, stay coupled to the van, crank high, remove bars, then uncouple.