Diodes vs. Std Lights

I think that one of the main reasons for the limited advice about towing or not towing 4 down is a CYA move, to avoid problems and warranty claims arising from folks not using common sense and relying on questions /answers here and in other forums hoping for somebody to respond, "Oh yes, you can tow your Lexus automatic transmission 4 down since I have done it for 20,000 miles and it hasn't blown up yet".
bumpy

I would bet that somewhere in the manual in fine print or in some other document connected to warranty it says that any modification to wiring or anything for that matter will void your warranty. They would never tell a customer how to modify the wire harness and brake lights in the manual.

I personally would put diodes in a stick shift car but not an electronically shifted automatic. Just too many unknowns when the alternate method takes the same time and costs about the same. Just my opinion.

Hank MI wrote:

Bumpyroad wrote:

Hank MI wrote:
Any manufacturers say you shouldn't tap into the tail lights with a diode setup?

I hear a lot of speculation on what might happen, maybe, if. Anybody actually had something bad happen?

why would a manufacturer put something like that into their owner's manual, etc.? lots of weird stuff folks could do and they have no reason to clutter up their literature with that kind of stuff.

bumpy

I don't know, why do they tell you what you need to do when recreational flat towing if the car is capable of it? If you do flat tow then obviously you'll need tail lights. Seems to me if they'll tell you to put the key in, turn to this position, put in neutral, pull this fuse, etc. why wouldn't they mention the use of diodes if it presented a potential problem?

-cut-

Because diodes aren't the only tail light solution. It is up to the operator of the tow vehicle to have security cables, breakaway, supplemental brakes, tail lights on the towed vehicle - as required by law. It's not the manufacturer's responsibility to tell you how to satisfy the towing laws in your state, or any state. If they did the towing section of the owners manual would be huge.

Simply put, because they are not required to provide any more than the bare minimum towing instructions (if required at all) - they don't.

Bumpyroad wrote:

Hank MI wrote:
Any manufacturers say you shouldn't tap into the tail lights with a diode setup?

I hear a lot of speculation on what might happen, maybe, if. Anybody actually had something bad happen?

why would a manufacturer put something like that into their owner's manual, etc.? lots of weird stuff folks could do and they have no reason to clutter up their literature with that kind of stuff.

bumpy

I don't know, why do they tell you what you need to do when recreational flat towing if the car is capable of it? If you do flat tow then obviously you'll need tail lights. Seems to me if they'll tell you to put the key in, turn to this position, put in neutral, pull this fuse, etc. why wouldn't they mention the use of diodes if it presented a potential problem?

Recreational flat towing is becoming more and more popular. If the car is capable of being flat towed, manufacturers go out of their way to tell you how because they know people want to do it. It would be a lot easier to just say no, you can't do it.

Also, my question regarding anyone having knowledge of diodes causing a problem was a serious one. My opinion is just that, my opinion, that's what the OP asked for. If someone has actual experience with diodes causing a problem then my opinion will change.

Hank MI wrote:
Any manufacturers say you shouldn't tap into the tail lights with a diode setup?

I hear a lot of speculation on what might happen, maybe, if. Anybody actually had something bad happen?

why would a manufacturer put something like that into their owner's manual, etc.? lots of weird stuff folks could do and they have no reason to clutter up their literature with that kind of stuff.

bumpy

FIRE UP wrote:

txhandgunner wrote:
Anybody have any strong preferences on "patch-in" diode brake lighting systems vs. simply routing separate lights???

From what I've seen, diodes are easier, but you risk voiding your warranty and/or frying your whole system....

txhandgunner
Well, as you can see, the old "Diode vs any other system" is, as usual, a presidential debate. This topic is on here and other RV forums usually about once a week. That's no biggie. Different folks come on the forums at different times and still need to know things.

Anyway, there really is no risk of "FRYING" ANY portion of the toads electrical system. I, as well as many others on here, have used the toads stock tail lights for decades and have had "0" issues. 10 different toads, (7) of them Jeeps, (1) 2011 Honda CRV and our present toad, an '11 GMC Sierra 1500 Extended Cab 4x4 have all been wired the exact same way.

I tie into the factory wiring, very close to the rear bulbs, (except for the Jeeps), strip a tiny bit of the insulation, solder in the incoming wire, tape and secure it. "DONE". Now, yes, I do install the diodes too.

But, my diodes, first, are not the "high end" expensive ones from Camping World or, any other RV supplier, they're the ones from Radio Shack, about $2.89 for a four pack. I install them in the toads light wires, about a few inches down from the "T" intersection I just created. Those are there to keep the signals from the coach, from traveling upstream to the toads electrical system and causing confusion.

This is all a matter of choice. If you want extra bulbs back there, then by all means, install them. For me, I just want the lights of the toad to act the same way they do when towing it, as the do when driving it. And that includes AMBER TURN SIGNALS and, RED brake lights. Your choice.
Scott

I guess a few people don't agree with us regarding the use of diodes. As far as a manufacturer saying to disconnect the battery, that's got nothing to do with the taillights. It has to do with leaving the key in while towing. Any manufacturers say you shouldn't tap into the tail lights with a diode setup?

I hear a lot of speculation on what might happen, maybe, if. Anybody actually had something bad happen?

az99 wrote:

Hank MI wrote:
Worst case if diode fails you'll turn on the corresponding front light at the same time.

With all due respect, do you know that for a fact? Is that also true of every make,year and model?
I was told by a very smart, highly trained Ford tech that some of the new vehicles have flash and signal functions and everything else triggered and controlled by the ECM or other computer (don't remember his exact works).
Frying the whole electrical system is not likely due to fuses etc. But would it be possible to feed enough power back to have the electronically shifted trans to go out of neutral (those solenoids draw less than an amp) or at minimum kick error codes?

This may be a case for the Mythbusters.:)

I believe this is part of why the smart car owners manual says to disconnect the battery when flat towing. It also warns that the car's computer could decide to engage the ABS brakes if it is active.

I have a battery disconnect switch installed. I also use diodes in the tail lights (Roadmaster's Combo Kit). I haven't had any problems.

Hank MI wrote:
Worst case if diode fails you'll turn on the corresponding front light at the same time.

With all due respect, do you know that for a fact? Is that also true of every make,year and model?
I was told by a very smart, highly trained Ford tech that some of the new vehicles have flash and signal functions and everything else triggered and controlled by the ECM or other computer (don't remember his exact works).
Frying the whole electrical system is not likely due to fuses etc. But would it be possible to feed enough power back to have the electronically shifted trans to go out of neutral (those solenoids draw less than an amp) or at minimum kick error codes?

This may be a case for the Mythbusters.:)

We have done it both ways . Our preference is to use separate lights. Most rear clusters have room for another LED light. In my experince it is also a quicker and less expensive install. JMHO

Hank MI wrote:
I used the diodes. To me it seemed easier to tap into the existing wires inside the trunk than try to add a 2nd bulb inside the taillight housing. Worst case if diode fails you'll turn on the corresponding front light at the same time. As for frying the toads electrical system, how? Both vehicles use a 12v system, the toads taillight wiring is use to having 12v going through it. Don't see how supplying that 12v from RV is any different. It's not like the MH uses 110v system.

I think the issue is "confusing" the computer in the car. have you priced replacing one of them lately?
bumpy