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Engine charging of coach batteries
I have a general question about how the (Class A) coach batteries are charged from the engine alternator while the engine is running. I am not at all sure that they even are so charged, as I cannot see a linkage to either my batteries or at the converter, but if there is such a link where would it be and how is it electrically configured? If such charging does take place, how fast is it and how quickly would a discharged (e.g. half discharged) battery take to become fully charged again? My motorhome is a Triple E Embassy, but this question also relates to what is typical in class A motorhomes - if there is a 'typical'. Thanks. Paul.9.6KViews0likes29CommentsRe: Unified Tow Brake help wanted
Thanks for the reply. No solution yet, but here is where I am at. I have changed the coach unit, car solenoid and cable (I found a complete new system at a reasonable price), but the problem is still there. So by elimination, it must be the power unit PM6001 that goes into the car. Unfortunately, the new unit has a fault (brake light disabling relay doesn't open), so I haven't been able to swap this out. AP Products are sending another PM6001, so when it arrives I will try it. Watch this space. Thanks, Paul. JCM wrote: I have been having a problem where the solenoid wouldn't retract any more but with a tech supports help we isolated (I hope) to a defective computer box - by measuring voltages to the solenoid. He said that that the solenoid almost never fails and that sounds so in your system. The only 2 other parts would be the controller on your dash and the computer box under the dash. If your brake away switch activates what you say I would think it is the darn computer. If you are in the US Amazon has them for about $319.00. I would spend the time and phone the company. Keep calling until you get a human. He was really helpful and I hope when my new computer arrives it will fix my problem. Good luck - it is a great system when working. Again reviewing your problem I am inclined to also question your dash unit since I believe that is the component that sets the proportional braking. Let us know the results.274Views0likes0CommentsRe: Unified Tow Brake help wanted
Thanks OP for that reply. I hadn't seen the troubleshooting guide - I don't know how I missed it. But there is quite a good bit of useful information in there, so I will get the MH from its storage yard and go through the relevant bits. Hopefully I can deduce enough to decide which item is at fault. I know it's not the cable from the solenoid, since it's not kinked and it operates smoothly and brings the brake pedal fully on and off freely, so it's either an electrical funny or one of the electronic boxes. And like you, my vacuum pump failed and I had to replace it with an aftermarket one. I don't know if it might be an issue or not (I'm inclining to think not), but will keep it in mind as I proceed.274Views0likes0CommentsUnified Tow Brake help wanted
I have a US Gear UTB, which I have just transferred from one car to another, and it doesn't seem to be working quite right. But first some history. The system was working fully when initially installed in the first car. Bit in this car, it hasn't been working properly of late, because the vacuum pump had quit, so there were no really obvious symptoms (and probably very little braking effect either). In the new car, I have installed a new vacuum pump. Wiring in the new car has been triple-checked and is OK. Here is what is now happening. The "proportional braking" aspect of the system isn't working: the car brakes are either off (when no braking is being called for) or fully on when any amount of MH braking is called for. When I apply the motorhome brakes, there is a 1-2 second delay where the car brakes don't seem to be doing anything, then a big jerk as the car brakes come on fully - and this is irrespective of the setting of the braking effort knob inside the motorhome. When I use the manual lever in the MH to operate the dingy brakes, one or two steps (LEDs on the MH unit) has no effect in the dingy, whereas 3 or 4 steps brings the dingy brakes on fully; there is no in-between. The MH unit and the UTB power module in the car seem to be communicating, according to the indicator lights. The system works as it should when I pull out the breakaway switch (full dingy braking). The mounting angle for the MH unit is within US Gear's specs. I am unhappy with this operation because of the stresses imposed on the towing system caused by the severe dingy braking, and also because of the possible premature wear on the car brakes, tires, and suspension system. So I would like to fix it. I like this system, and have gone to a lot of trouble to re-install it, so would prefer not to switch to something different. I assume that the problem is either with the control unit in the motorhome or with the power module in the dingy, and I would like some help or suggestions as to how I can determine which item is faulty. Both are difficult to obtain as spares and are expensive, so I don't want to guess wrong. Is there anybody out there sufficiently savvy about this system who can help me through this, and help me determine where the fault is? Thanks. Paul. PS. I posted an briefer description of this problem as an appendix to an earlier post (Vacuum pump for Unified Tow Brake), but thought it better for it to have its own topic.1.8KViews0likes4CommentsRe: Vacuum pump for Unified Tow Brake
i finally installed a generic vacuum pump (ACDelco 20804130 GM Original Equipment Power Brake Booster Auxiliary Pump Assembly, from Amazon), and it seems to operate the brakes OK. I installed it in place of the original US Gear pump, but because it draws quite a lot more current than the original I used an inexpensive automotive relay (with snubbing diode!) to drive it. The pump runs when it should, and the brakes come full-on when I pull out the breakaway switch, suggesting that it works. But I have another issue, one that may or may not be related to the pump. The "proportional" feature of the system no longer operates: the brakes are either off or fully on - on when braking in the motorhome, off when driving normally. The motorhome unit and the car controller seem to be communicating OK judging by the indicator lights in the MH, and the manual lever in the MH brings on the car brakes fully. But when I operate the MH brakes, there is a second's delay then the car brakes come on fiercely, resulting in quite a severe jerk (and probably stress on the towing system). While I have still one or two things to try, I wondered whether anyone has seen this, and I would welcome suggestions to help me decide whether it is a fault in the MH unit or the car control unit. Or whether it's just a matter of adjustment. Thanks.310Views0likes0CommentsRe: Dingy wiring for rear lights on Forester
Thanks for the thoughts, and the implied undesirability of magnetic rabbit's ears. I decided to dig deeper to see what I cold do. I think that the main difficulty I foresaw was getting to the wiring behind all the interior trim at the rear. Not wanting to cause damage by pulling in the wrong places or removing the wrong bolts, I finally went to my Subaru dealer and asked him how to get at the wiring. He was very helpful, and I think I can do what I need to do. If all else fails, ask the experts!167Views0likes0CommentsDingy wiring for rear lights on Forester
I have a new 2015 Forester which I will tow, and am looking at dealing with the rear lights (brakes, turn indicators, running lights), which have to be slaved to the motorhome's. The usual approach to using the car's own lights is to run wires to the rear of the car and use diodes to isolate the car and motorhome lighting circuits, and this has worked well on my previous two dingys. It looks a little harder on the Forester because of the isolated nature of the rear light clusters and the limited space therein to mount diodes. Not to mention all the interior trim hiding the wiring. So I am wondering whether anybody has any advice on how to set about this. Or is it more common to use the magnetic "rabbit's ears" style of lights, and put them on the roof just when towing? What has everybody done? Thanks for any suggestions. Paul.1.2KViews0likes4CommentsVacuum pump for Unified Tow Brake
I have been using the US Gear Unified Tow Brake in my last two tow vehicles, and now want to install it in a third. Unfortunately, it seems as if the vacuum pump has failed: testing the system before removing it resulted in only a small movement of the brake pedal (suggesting low vacuum), and testing the pump after removal showed virtually no air movement and no appreciable vacuum (although the motor still runs). My motorhome brakes are also showing evidence of overheating, again suggesting that the dingy brakes are not all that effective. I have emailed US Gear to see about a replacement pump, but have had no reply. I have also researched availability on the internet, and find that it will set me back over $500 even assuming that the advertisers have stock. So I am considering using a generic vacuum pump as a replacement, as I can get one for a quarter of the price. But before I do, I want to be sure there are likely to be no technical issues. The way the pump and the electric solenoid are wired to the same terminal on the power module leads me to question whether there is something I need to be aware of, as the pump continues running well after the solenoid has become idle. Has anyone tried using a non-US-Gear vacuum pump with this system? Does anyone have any technical insight as to how the pump and solenoid work together? I am electrically savvy enough to be able to work around whatever issues there might be, as long as I know what they are. For example, I may use a relay for such a generic pump to be sure I don't overload the Power Module, etc. Any thoughts on this would be most welcome. Thanks.2.4KViews0likes3Comments
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